HK1204089B - Movable body drive system and method, pattern formation apparatus and method, exposure apparatus and method, device manufacturing method - Google Patents

Description

Moving body drive system and method, pattern forming apparatus and method, exposure apparatus and method, and device manufacturing method

This application is a divisional application of PCT patent application with application No. 200780009923.1 (international application No. PCT/JP2007/067039, international application date 2007: 8/31/2007), entitled "moving body driving system and method, pattern forming apparatus and method, exposure apparatus and method, device manufacturing method".

Technical Field

The present invention relates to a moving body drive system and a moving body drive method, a pattern forming apparatus and method, a device manufacturing method, and a determination method, and more particularly, to a moving body drive system and a moving body drive method for driving a moving body along a predetermined plane, a pattern forming apparatus provided with the moving body drive system, a pattern forming method using the moving body drive method, an exposure apparatus provided with the moving body drive system, an exposure method using the moving body drive method, a device manufacturing method using the pattern forming method, and a determination method for determining correction information for encoder system measurement values for measuring positional information of the moving body in a predetermined direction.

Background

Conventionally, in a photolithography process for manufacturing a microdevice (an electronic device or the like) such as a semiconductor device or a liquid crystal display device, a reduction projection exposure apparatus of a step-and-repeat method (a so-called stepper), a reduction projection exposure apparatus of a step-and-scan method (a so-called scanning stepper (also called a scanner)), or the like is used in a relatively large number of cases.

In such an exposure apparatus, a wafer stage holding a wafer is driven in XY two-dimensional directions by, for example, a linear motor or the like in order to transfer a pattern of a reticle (or a mask) to a plurality of irradiation regions on the wafer. In particular, the scanning stepper can drive not only the wafer stage but also the reticle stage in the scanning direction by a linear motor or the like at a predetermined stroke. For measurement of a reticle stage or a wafer stage, a laser interferometer having high resolution and good stability of long-term measurement values is generally used.

However, since the position of the stage is required to be controlled with higher accuracy due to the miniaturization of the pattern accompanying the high integration of the semiconductor device, the short-term fluctuation of the measurement value due to the fluctuation of the temperature of the atmosphere on the beam optical path of the laser interferometer currently accounts for a considerable proportion of the overlay accuracy.

On the other hand, although an encoder is known as a measuring device other than a laser interferometer used for measuring the position of the stage, since the encoder uses a scale, the scale lacks mechanical long-term stability (shift of the grating pitch, fixed position shift, thermal expansion, and the like), and has a disadvantage that linearity of the measured value is lacking as compared with the laser interferometer, and long-term stability is poor.

In view of the drawbacks of the laser interferometer and the encoder, various devices have been proposed which measure the position of the stage by using a laser interferometer and an encoder (a position detection sensor using a diffraction grating) in combination (see patent documents 1 and 2, etc.).

Further, although the measurement resolution of conventional encoders is inferior to that of interferometers, encoders having measurement analysis capability similar to or better than that of laser interferometers have recently appeared (see, for example, patent document 3).

However, when an encoder is used for position measurement in the moving plane of a wafer stage of an exposure apparatus, for example, and when the position measurement of the wafer stage provided with a scale (grating) is performed using 1 encoder head, if relative movement other than the measurement-required direction (measurement direction) occurs between the head and the scale, a change in the measured value (count) is often detected, and a measurement error occurs. In addition, when an encoder is actually applied to the wafer stage of the exposure apparatus, a plurality of encoder heads must be used for 1 scale, and there is a problem that an error occurs in the count value of the encoder due to, for example, a difference in inclination (optical axis inclination) between the encoder heads.

[ patent document 1 ] Japanese patent laid-open No. 2002-151405

[ patent document 2 ] Japanese patent laid-open No. 2004-101362

[ patent document 3 ] Japanese patent laid-open No. 2005-308592

Disclosure of Invention

The inventors performed various simulations to understand the influence of the relative displacement between the head and the scale in the non-measurement direction on the encoder measurement value when the stage position of the exposure apparatus is measured by the reflective optical encoder. As a result, it is found that the count value of the encoder is not only sensitive to changes in the attitude of the stage in the pitch direction and yaw direction, but also depends on changes in the position in the direction perpendicular to the stage moving surface.

The present invention has been made in view of the simulation results of the above-described inventors, and in view 1 thereof, a moving body driving system for driving a moving body substantially along a predetermined plane, the moving body driving system comprising: an encoder including a head that irradiates detection light to a scale having a grid whose periodic direction is a predetermined direction parallel to the predetermined plane and receives reflected light from the scale, and that measures positional information of the movable body in the predetermined direction; and a driving device that drives the movable body in the predetermined direction based on a measurement value of the encoder and correction information corresponding to position information of the movable body in a direction different from the predetermined direction at the time of the measurement.

Accordingly, the drive device drives the movable body in the predetermined direction based on the measurement value of the encoder for measuring the positional information of the movable body in the predetermined direction (measurement direction) and the correction information corresponding to the positional information of the movable body in the direction (non-measurement direction) different from the predetermined direction in the measurement. That is, the movable body is driven in the predetermined direction based on the encoder measurement value corrected by the correction information for correcting the encoder measurement error caused by the relative displacement between the head and the scale in the non-measurement direction. Therefore, the movable body can be driven in a predetermined direction with good accuracy without being affected by relative movement between the head and the scale in a direction to be measured (measurement direction).

According to a 2 nd aspect of the present invention, there is provided a pattern forming apparatus comprising: a movable body that carries an object and can hold the object to move substantially along a moving surface; a patterning device that forms a pattern on the object; and a movable body driving system for driving the movable body in order to form a pattern on the object.

Accordingly, the object on the movable body driven with good accuracy using the movable body driving system of the present invention is patterned by the patterning device, and the pattern can be formed on the object with good accuracy.

A 3 rd aspect according to the present invention is a 1 st exposure apparatus for forming a pattern on an object by irradiation of an energy beam, characterized by comprising: a patterning device configured to irradiate the object with an energy beam; and a movable body drive system according to the present invention for driving a movable body on which the object is mounted, in order to perform relative movement between the energy beam and the object.

Accordingly, the movable body on which the object is mounted can be driven with good accuracy using the movable body driving system of the present invention so that the energy beam irradiated from the patterning device to the object and the object move relative to each other. Therefore, a pattern can be formed on an object with good accuracy by scanning exposure.

A 4 th aspect of the present invention is a 2 nd exposure apparatus for exposing an object with an energy beam, characterized by comprising: a movable body that holds the object and is movable in at least the 1 st and 2 nd directions orthogonal to each other in a predetermined plane; an encoder system that includes one of a grating portion and a head unit provided on one surface of the movable body that holds the object, and the other of the grating portion and the head unit provided opposite to the one surface of the movable body, and measures position information of the movable body in at least one of the 1 st and 2 nd directions; and a drive device that drives the movable body within the predetermined plane based on measurement information of an encoder system and positional information of the movable body in a direction different from the 1 st and 2 nd directions.

Accordingly, the movable body can be driven in the measurement direction of the encoder system with good accuracy without being affected by displacement of the movable body in a direction other than the measurement direction of the encoder system, and the object held on the movable body can be exposed with good accuracy.

According to a 5 th aspect of the present invention, there is provided a 3 rd exposure apparatus for exposing an object with an energy beam, comprising: a movable body that holds the object, is movable in at least first and second directions orthogonal to each other in a predetermined plane, and is inclined with respect to the predetermined plane; an encoder system that includes one of a grating portion and a head unit provided on one surface of the movable body that holds the object, and the other of the grating portion and the head unit provided opposite to the one surface of the movable body, and measures position information of the movable body in at least one of the 1 st and 2 nd directions; and a driving device that drives the movable body within the predetermined plane based on measurement information of the encoder system and tilt information of the movable body.

Accordingly, the movable body can be driven in the measurement direction of the encoder system with good accuracy without being affected by the inclination (displacement in the inclination direction) of the movable body, and the object held on the movable body can be exposed with good accuracy.

According to a 6 th aspect of the present invention, there is provided a 4 th exposure apparatus for exposing an object with an energy beam, comprising: a movable body that holds the object and is movable in at least the 1 st and 2 nd directions orthogonal to each other in a predetermined plane; an encoder system that includes one of a grating portion and a head unit provided on one surface of the movable body that holds the object, and the other of the grating portion and the head unit provided opposite to the one surface of the movable body, and measures position information of the movable body in at least one of the 1 st and 2 nd directions; and a driving device that drives the movable body within the predetermined plane based on measurement information of an encoder system and characteristic information of the head unit that causes a measurement error of the encoder system.

Accordingly, the movable body can be driven with good accuracy in the measurement direction of the encoder system without being affected by the measurement error of the encoder system due to (the characteristics of) the head unit, and the object held on the movable body can be exposed with good accuracy.

A 7 th aspect of the present invention is a 5 th exposure apparatus for exposing an object with an energy beam, comprising: a movable body that holds the object and is movable in at least the 1 st and 2 nd directions orthogonal to each other in a predetermined plane; an encoder system that includes one of a grating portion and a head unit provided on one surface of the movable body that holds the object, and the other of the grating portion and the head unit provided opposite to the one surface of the movable body, and that measures position information of the movable body in at least one of the 1 st and 2 nd directions; and a drive device that drives the movable body within the predetermined plane based on measurement information of an encoder system so as to compensate for a measurement error of the encoder system generated by the head unit.

Accordingly, the movable body can be driven in the measurement direction of the encoder system with good accuracy without being affected by the measurement error of the encoder system caused by the head unit, and the object held on the movable body can be exposed with good accuracy.

According to an 8 th aspect of the present invention, there is provided a moving body driving method for driving a moving body substantially along a predetermined plane, comprising: and measuring position information of the movable body in the predetermined direction using an encoder including a head that irradiates detection light to a scale having a grating whose periodic direction is a predetermined direction parallel to the predetermined plane and receives reflected light from the scale, and driving the movable body in the predetermined direction based on measurement values of the encoder and correction information corresponding to position information of the movable body in a direction different from the predetermined direction at the time of the measurement.

In this way, the movable body is driven in the predetermined direction based on the encoder measurement value corrected by the correction information for correcting the encoder measurement error caused by the relative displacement between the head and the scale in the non-measurement direction. Therefore, the movable body can be driven in a predetermined direction with good accuracy without being affected by relative movement between the head and the scale in a direction to be measured (measurement direction).

A 9 th aspect of the present invention is a pattern forming method characterized by comprising: a step of loading an object on a movable body movable on a moving surface; and a step of driving the movable body by using a movable body driving method according to the present invention in order to form a pattern on the object.

Accordingly, the pattern can be formed on the object with good accuracy by forming the pattern on the object on the movable body driven with good accuracy by using the movable body driving method of the present invention.

A 10 th aspect of the present invention is a device manufacturing method including a pattern forming step, characterized in that: in the pattern forming step, a pattern is formed on the substrate by using the pattern forming method of the present invention.

An 11 th aspect according to the present invention is a 1 st exposure method of forming a pattern on an object by irradiation of an energy beam, characterized in that: in order to perform the relative movement between the energy beam and the object, the moving body on which the object is mounted is driven using the moving body driving method of the present invention.

Accordingly, in order to perform relative movement between the energy beam irradiated to the object and the object, the moving body on which the object is mounted is driven with good accuracy by using the moving body driving method of the present invention. Therefore, a pattern can be formed on an object with good accuracy by scanning exposure.

A 12 th aspect of the present invention is a 2 nd exposure method for exposing an object with an energy beam, characterized in that: loading an object on a movable body movable in at least first and second directions orthogonal to each other in a predetermined plane; the moving body is driven within the predetermined plane based on measurement information of an encoder system that has one of a grating portion and a head unit provided on one surface of the moving body on which the object is mounted and the other surface of the moving body facing the one surface of the moving body and measures position information of the moving body in at least one of the 1 st and 2 nd directions and position information of the moving body in a direction different from the 1 st and 2 nd directions.

Accordingly, the movable body can be driven in the measurement direction of the encoder system with good accuracy without being affected by displacement of the movable body in a direction other than the measurement direction of the encoder system, and the object held on the movable body can be exposed with good accuracy.

A 13 th aspect of the present invention is a 3 rd exposure method for exposing an object with an energy beam, characterized in that: the method includes the steps of mounting an object on a movable body that is movable in at least first and second directions perpendicular to each other in a predetermined plane and is inclined with respect to the predetermined plane, and driving the movable body in the predetermined plane based on measurement information of an encoder system that is provided with a grating portion and a head unit on one surface of the movable body on which the object is mounted and is provided with the other surface facing the one surface of the movable body so as to measure position information of the movable body in at least one of the first and second directions, and inclination information of the movable body.

Accordingly, the movable body can be driven in the measurement direction of the encoder system with good accuracy without being affected by the inclination (displacement in the inclination direction) of the movable body, and the object held on the movable body can be exposed with good accuracy.

A 14 th aspect of the present invention is a 4 th exposure method for exposing an object with an energy beam, characterized in that: loading an object on a movable body movable in at least first and second directions orthogonal to each other in a predetermined plane; and driving the movable body within the predetermined plane based on measurement information of an encoder system and characteristic information of the head unit that causes a measurement error of the encoder system, wherein the encoder system is provided with one of a grating portion and the head unit on one surface of the movable body on which the object is mounted, and the other is provided to face one surface of the movable body, and measures position information of the movable body in at least one of the 1 st and 2 nd directions.

Accordingly, the movable body can be driven with good accuracy in the measurement direction of the encoder system without being affected by the measurement error of the encoder system due to (the characteristics of) the head unit, and the object held on the movable body can be exposed with good accuracy.

A 15 th aspect of the present invention is a 5 th exposure method for exposing an object with an energy beam, characterized in that: loading an object on a movable body movable in at least first and second directions orthogonal to each other in a predetermined plane; and driving the movable body within the predetermined plane based on measurement information of an encoder system that has a grating portion and a head unit on one surface of the movable body on which the object is mounted, and has the other surface opposite to the one surface of the movable body, so as to measure position information of the movable body in at least one of the 1 st and 2 nd directions, so as to compensate for measurement error information of the encoder system generated by the head unit.

Accordingly, the movable body can be driven in the measurement direction of the encoder system with good accuracy without being affected by the measurement error of the encoder system caused by the head unit, and the object held on the movable body can be exposed with good accuracy.

According to a 16 th aspect of the present invention, there is provided a device manufacturing method including a photolithography step, characterized in that: the lithography step is a step of exposing the sensitive object to light using the exposure method according to any one of the exposure methods 2 to 5 of the present invention to form a pattern on the sensitive object.

According to a 17 th aspect of the present invention, there is provided a 1 st determining method for determining correction information of a measurement value of an encoder system including a head which is provided on a movable body movable substantially along a predetermined plane and which irradiates detection light to a scale having a grating in which a predetermined direction is a periodic direction and receives reflected light from the scale, and which measures position information of the movable body in the predetermined direction in a plane parallel to the predetermined plane, the determining method comprising: changing the movable body to a plurality of different postures, and moving the movable body in a direction orthogonal to the predetermined plane within a predetermined stroke range while irradiating detection light from a head as a target to a specific region of the scale in a state where the posture of the movable body is maintained for each posture, and sampling a measurement result of the encoder system during the movement; and obtaining correction information of the measured value of the encoder system corresponding to position information of the moving body in a direction different from the predetermined direction by performing a predetermined calculation based on the sampling result.

In this way, the movable body is changed to a plurality of different postures, and in each posture, the movable body is moved in a direction orthogonal to the predetermined plane within a predetermined stroke range while irradiating the detection light from the specific region of the head on the scale, and the measurement result of the encoder is sampled during the movement. In this way, it is possible to obtain information (for example, a characteristic curve) on the change in position of the moving body in the direction orthogonal to the predetermined plane, in accordance with the encoder system measurement value for each posture. Then, based on the sampling result, that is, based on the information on the change in the position of the moving body in the direction orthogonal to the predetermined plane in accordance with the encoder system measurement value for each posture, predetermined calculation is performed to obtain correction information of the encoder system measurement value corresponding to the information on the position of the moving body in a direction (non-measurement direction) different from the predetermined direction. Therefore, correction information for correcting the encoder system measurement error caused by the relative change between the head and the scale in the non-measurement direction can be determined by a simple method.

According to an 18 th aspect of the present invention, there is provided a 2 nd determining method for determining correction information of a measurement value of an encoder system including a plurality of head units constituting an encoder which is provided with a moving body movable substantially along a predetermined plane, irradiates detection light to a scale having a grid with a periodic direction in a predetermined direction, and receives reflected light from the scale, and measures position information of the encoder in the predetermined direction in a plane parallel to the predetermined plane, the determining method comprising: changing the movable body to a plurality of different postures, moving the movable body in a direction orthogonal to the predetermined plane within a predetermined stroke range while irradiating detection light from a target head to a specific region of the scale in a state where the posture of the movable body is maintained for each posture, and sampling an encoder measurement result constituted by the target head during the movement, the operation being performed for the plurality of heads; and obtaining correction information of the measured values of the plurality of encoders corresponding to directional position information of the moving object in a direction different from the predetermined direction by performing a predetermined calculation based on the sampling result.

Accordingly, it is possible to determine correction information for correcting the encoder system measurement error caused by the relative change between the head and the scale in the non-measurement direction and determine correction information for correcting the geometric measurement error (cosine error) caused by the displacement of each head simultaneously by a simple method.

Drawings

Fig. 1 is a schematic configuration diagram showing an exposure apparatus according to an embodiment.

Fig. 2 is a plan view showing the stage device of fig. 1.

Fig. 3 is a plan view showing the arrangement of various measuring devices (an encoder, an alignment system, a multipoint AF system, a Z sensor, and the like) provided in the exposure apparatus of fig. 1.

Fig. 4(a) is a plan view showing the wafer stage, and fig. 4(B) is a schematic side view showing a partial cross section of the wafer stage.

Fig. 5(a) is a plan view showing the measurement stage, and fig. 5(B) is a schematic side view showing a partial cross section of the measurement stage.

FIG. 6 is a block diagram showing a main configuration of a control system of an exposure apparatus according to an embodiment.

Fig. 7(a) and 7(B) are diagrams for explaining the position measurement of the wafer stage in the XY plane and the connection of the measurement values between the heads by the plurality of encoders including the plurality of heads arranged in an array, respectively.

Fig. 8(a) is a diagram showing one example of the configuration of the encoder, and fig. 8(B) is a diagram illustrating the configuration in which this measurement error occurs, and is a diagram for explaining the relationship between the incident light and the diffracted light of the light beam in the encoder head and the reflection type diffraction grating.

Fig. 9(a) is a diagram showing a case where the clock value does not change even when relative motion in a non-measurement direction occurs between the head and the scale of the encoder, and fig. 9(B) is a diagram showing an example of a case where relative motion in a non-measurement direction occurs between the head and the scale of the encoder.

Fig. 10(a) to 10(D) are diagrams for explaining a case where the count value of the encoder changes and a case where the count value does not change when relative movement in the non-measurement direction occurs between the head and the scale.

Fig. 11 a and 11B are diagrams for explaining an operation for acquiring correction information for correcting a measurement error of the encoder (encoder No. 1) caused by a relative movement between the head and the scale in a non-measurement direction.

Fig. 12 is a graph showing a measurement error of the encoder with respect to a change in Z position when the pitch amount θ x is a.

Fig. 13 is a diagram for explaining an operation for acquiring correction information for correcting a measurement error of an encoder (encoder No. 2) caused by a relative movement between the head and the scale in a non-measurement direction.

Fig. 14 is a diagram showing the states of the wafer stage and the measurement stage in a state where the wafer on the liquid wafer stage is subjected to step-and-scan exposure.

Fig. 15 is a diagram showing the state of the wafer stage and the measurement stage after the exposure is completed, from the state in which the two stages are separated to the state in which the two stages are in contact.

Fig. 16 is a diagram showing the states of the wafer stage and the measurement stage when the measurement stage moves in the-Y direction and the wafer stage moves to the unload position while maintaining the Y-axis positional relationship between the wafer stage and the measurement stage.

Fig. 17 shows a state of the wafer stage and the measurement stage when the measurement stage reaches a position where the Sec-BCHK (time interval) is to be performed.

Fig. 18 is a diagram showing the state of the wafer stage and the measurement stage when the wafer stage is moved from the unloading position to the loading position while performing Sec-BCHK (time interval).

Fig. 19 is a diagram showing the states of the wafer stage and the measurement stage when the measurement stage moves to the optimum emergency stop standby position and the wafer is mounted on the wafer stage.

Fig. 20 is a diagram showing the states of the two stages when the wafer stage is moving to the position where the first half of the Pri-BCHK processing is performed while the measurement stage is waiting at the optimum emergency stop standby position.

FIG. 21 is a schematic representation of the use of alignment systems AL1, AL2₂,AL2₃And a diagram of states of the wafer stage and the measurement stage when the alignment marks attached to the three first alignment irradiation areas are simultaneously detected.

Fig. 22 is a diagram showing states of the wafer stage and the measurement stage when the focus correction first half process is performed.

FIG. 23 is a schematic representation of the use of alignment systems AL1, AL2₁～AL2₄And a diagram of the states of the wafer stage and the measurement stage when the alignment marks attached to the five second alignment irradiation areas are simultaneously detected.

Fig. 24 is a diagram showing the states of the wafer stage and the measurement stage when at least one of the second half processing of Pri-BCHK and the second half processing of focus correction is performed.

FIG. 25 is a schematic representation of the use of alignment systems AL1, AL2₁～AL2₄And a diagram of the states of the wafer stage and the measurement stage when the alignment marks attached to the five third alignment irradiation areas are simultaneously detected.

FIG. 26 is a schematic representation of the use of alignment systems AL1, AL2₂,AL2₃And a diagram of the states of the wafer stage and the measurement stage when the alignment marks attached to the three fourth alignment irradiation areas are simultaneously detected.

Fig. 27 is a diagram showing the states of the wafer stage and the measurement stage at the time of completion of the focus matching.

Fig. 28 is a flowchart for explaining an embodiment of the device manufacturing method.

Fig. 29 is a flowchart showing a specific example of step 204 in fig. 28.

Description of the reference numerals

5: a liquid supply device; 6: a liquid recovery device; 8: a local immersion liquid device; 10: an illumination system; 11: a reticle stage drive system; 12: a base; 14: a liquid immersion area; 15: moving the mirror; 16, 18: a Y interferometer; 17a,17b, 19a,19 b: a reflective surface; 20: a main control device; 28: a plate body; 28 a: a 1 st lyophobic area; 28 b: a 2 nd lyophobic area; 28b₁: part 1 area; 28b₂: a 2 nd partial region; 30: measuring a plate; 31A: a liquid supply tube; 31B: a liquid recovery pipe; 32: a mouth unit; 34: a memory; 36: a frame body; 37, 38: a grating line; 39X₁，39X₂: an X scale; 39Y of₁，39Y₂: a Y scale; 40: a lens barrel; 41A, 41B: a plate-like member; 42: a mounting member; 43A, 43B: a Z interferometer; 44: a light receiving system; 45: an aerial image measuring device; 46: a CD rod; 47A, 47B: a shock absorber; 47A, 48B: a brake mechanism; 49A, 49B: a shutter; 50: a stage device; 51A, 51B: an opening; 52: a reference grating; 54: support for supportingA member; 56₁～56₄: an arm; 58₁～58₄: a vacuum pad; 60₁～60₄: a rotation driving mechanism; 62A to 62D: a reading head unit; 64: a Y read head; 64 a: an illumination system; 64 b: an optical system; 64 c: a light receiving system; 64y₁，64y₂: a Y read head; 66: an X read head; 68: an adjustment device; 70A, 70C: a Y linear encoder; 70B, 70D: an X linear encoder; 70E, 70F: a Y-axis linear encoder; 72a to 72 d: a Z sensor; 74_1，1～74_2，6: a Z sensor; 76_1,1～76_2,6: a Z sensor; 78: a local air conditioning system; 80, 81: an X-axis fixing member; 82,84,83, 85: a Y-axis movable member; 86, 87: a Y-axis fixing member; 90 a: an illumination system; 90 b: a light receiving system; 91, 92: a stage body; 94: an illuminance unevenness sensor; 96: an aerial image measurer; 98: a wavefront aberration measuring device; 99: a sensor group; 100: an exposure device; 116: a reticle interferometer; 118: an interferometer system; 124: a stage drive system; 126, 130: an X interferometer; 142, 143: a fixing member; 144A, 145A: a light emitting section; 144B, 145B: a light receiving section; 191: a front end lens; AL 1: a primary alignment system; AL2₁～AL2₄: a secondary alignment system; AS: irradiating the area; AX: an optical axis; b4₁，B4₂，B5₁，B5₂: a ranging beam; CL, LL: a centerline; CT: an up-down moving pin; FM: a fiducial marker; IA: an exposure area; IAR: an illumination area; IBX1, IBX2, IBY1, IBY 2: a ranging beam; IL: light for illumination; l2a, L2 b: a lens; LB: a laser beam; LB₁，LB₂: a light beam; LD: a semiconductor laser; and (3) LP: a loading position; and (Lq): a liquid; LH, LV: a straight line; m: masking; MTB: a measuring table; MST: a measuring platform deck; o: a center of rotation; PBS: a polarizing beam splitter; PL: a projection optical system; PU (polyurethane): a projection unit; r: a reticle; r1a, R1b, R2a, R2 b: a mirror; RG: a reflection type diffraction grating; RST: a reticle stage; SL: measuring the slit pattern by space image; UP: an unloading position; w: a wafer; WP1a, WP1 b: a lambda/4 plate; WTB: a wafer stage; WST: a wafer carrier.

Detailed Description

An embodiment of the present invention will be described below with reference to fig. 1 to 27.

Fig. 1 schematically shows a configuration of an exposure apparatus 100 according to one embodiment. The exposure apparatus 100 is a step-and-scan type exposure apparatus, a so-called scanner. As described later, in the present embodiment, the projection optical system PL is provided, and hereinafter, a direction parallel to the optical axis AX of the projection optical system PL is referred to as a Z-axis direction, a direction in which the reticle and the wafer are relatively scanned in a plane orthogonal to the Z-axis direction is referred to as a Y-axis direction, a direction orthogonal to the Z-axis and the Y-axis is referred to as an X-axis direction, and directions of rotation (inclination) about the X-axis, the Y-axis, and the Z-axis are referred to as θ X, θ Y, and θ Z directions, respectively.

The exposure apparatus 100 includes: an illumination system 10; a reticle stage RST for holding a reticle R illuminated with exposure illumination light (hereinafter referred to as "illumination light" or "exposure light") IL of the illumination system 10; a projection unit PU including a projection optical system PL for projecting the illumination light IL emitted from the reticle R onto the wafer W; a stage device 50 having a wafer stage WST and a measurement stage MST; and a control system for the above apparatus. Wafer W is mounted on wafer stage WST.

The illumination system 10 includes a light source, an illumination optical system having an illuminance uniformizing optical system including an optical integrator and the like, a reticle blind and the like (none of which are shown), as disclosed in, for example, japanese patent application laid-open No. 2001-313250 (corresponding to U.S. patent application publication No. 2003/0025890). The illumination system 10 illuminates a slit-shaped illumination region on a reticle R defined by a reticle blind (mask system) with illumination light (exposure light) IL at a substantially uniform illuminance. Here, as the illumination light IL, an ArF excimer laser (wavelength 193nm) is used as an example. Further, as the optical integrator, for example, a fly eye lens, a rod integrator (internal reflection type integrator), a diffractive optical element, or the like can be used.

A reticle R having a circuit pattern or the like formed on its pattern surface (the lower surface in fig. 1) is fixed to the reticle stage RST by, for example, vacuum suction. Reticle stage RST can be driven very slightly in the XY plane by reticle stage driving system 11 (not shown in fig. 1, see fig. 6) including, for example, a linear motor or the like, and can be driven in a predetermined scanning direction (the Y-axis direction in the left-right direction in the drawing of fig. 1) at a predetermined scanning speed.

Positional information (including rotation information in the θ z direction) of reticle stage RST within the moving plane is detected at any time with an analysis capability of, for example, about 0.5 to 1nm by a reticle laser interferometer (hereinafter referred to as "reticle interferometer") 116 via moving mirror 15 (actually, a Y moving mirror having a reflecting surface orthogonal to the Y axis direction and an X moving mirror having a reflecting surface orthogonal to the X axis direction are provided). The measurement values of reticle interferometer 116 are transmitted to main control device 20 (not shown in fig. 1, see fig. 6), and main control device 20 calculates the position of reticle stage RST in the X-axis direction, the Y-axis direction, and the θ z direction from the measurement values of reticle interferometer 116, and controls reticle stage drive system 11 based on the calculation result to control the position (and speed) of reticle stage RST. Instead of the movable mirror 15, a reflecting surface (corresponding to the reflecting surface of the movable mirror 15) may be formed by mirror-finishing an end surface of the reticle stage RST. Further, reticle interferometer 116 may measure positional information of reticle stage RST in at least one of the Z-axis direction, θ x direction, and θ y direction.

Projection unit PU is disposed below reticle stage RST in fig. 1. The projection unit PU includes: a lens barrel 40; and a projection optical system PL having a plurality of optical elements held in a predetermined positional relationship in the lens barrel 40. As the projection optical system PL, for example, a refractive optical system including a plurality of lenses (lens units) arranged along an optical axis AX parallel to the Z-axis direction is used. The projection optical system PL is, for example, telecentric on both sides and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, 1/8 times, or the like). Thus, when the illumination area IAR is illuminated with the illumination light IL from the illumination system 10, a reduced circuit pattern image (a partial reduced circuit pattern image) of the reticle in the illumination area IAR is formed via the projection optical system PL (projection unit PU) and liquid Lq (see fig. 1) in an area (exposure area IA) conjugate to the illumination area IAR on the wafer W, which is disposed on the 2 nd surface (image surface) side and coated with a resist (photosensitive agent), by the illumination light IL of the reticle R, which passes through the 1 st surface (object surface) of the projection optical system PL and is disposed substantially coincident with the pattern surface thereof. Next, by synchronously driving reticle stage RST and wafer stage WST, the reticle is moved in the scanning direction (Y-axis direction) with respect to illumination area IAR (illumination light IL), and wafer W is moved in the scanning direction (Y-axis direction) with respect to exposure area (illumination light IL), whereby one irradiation area (divided area) on wafer W is scanned and exposed, and the pattern of the reticle is transferred to the irradiation area. That is, in the present embodiment, a pattern is generated on the wafer W by the illumination system 10, the reticle, and the projection optical system PL, and the pattern is formed on the wafer W by exposure of the sensitive layer (resist layer) on the wafer W with the illumination light IL. Although not shown here, projection unit PU is mounted on a lens barrel holder supported by three support columns via vibration isolation mechanisms, but projection unit PU may be suspended and supported on a main frame member, not shown, disposed above projection unit PU, a base member, on which reticle stage RST is disposed, or the like, as disclosed in, for example, pamphlet of international publication No. 2006/038952.

In the exposure apparatus 100 of the present embodiment, in order to perform exposure using the liquid immersion method, the nozzle unit 32 constituting a part of the local liquid immersion apparatus 8 is provided so as to surround and hold the periphery of the lower end portion of the lens barrel 40 which surrounds and holds the optical element, here, the lens (hereinafter, also referred to as "tip lens") 191, which constitutes the projection optical system PL on the most image plane side (wafer W side). In the present embodiment, as shown in fig. 1, the lower end surface of the nozzle unit 32 is set to be substantially flush with the lower end surface of the distal end lens 191. The nozzle unit 32 includes a supply port and a recovery port for the liquid Lq, a lower surface disposed opposite to the wafer W and provided with the recovery port, and a supply flow path and a recovery flow path connected to the liquid supply tube 31A and the liquid recovery tube 31B, respectively. As shown in fig. 3, the liquid supply tube 31A and the liquid recovery tube 31B are inclined 45 ° in a plan view (viewed from above) with respect to the X-axis direction and the Y-axis direction, and are arranged symmetrically with respect to a line LV in the Y-axis direction passing through the optical axis AX of the projection optical system PL.

The liquid supply pipe 31A is connected to the other end of a supply pipe (not shown in fig. 1, see fig. 6) of the liquid supply device 5 at one end thereof, and the liquid recovery pipe 31B is connected to the other end of a recovery pipe (not shown in fig. 1, see fig. 6) of the liquid recovery device 6 at one end thereof.

The liquid supply device 5 includes a liquid tank, a pressure pump, a temperature control device, and a valve for controlling supply and stop of liquid to the liquid supply pipe 31A. For example, a flow rate control valve capable of not only supplying and stopping a liquid but also adjusting a flow rate is preferably used as the valve. The temperature control device adjusts the temperature of the liquid in the liquid tank to the same level as the temperature in a processing chamber (not shown) in which the exposure apparatus is housed. Further, the tank for supplying the liquid, the pressure pump, the temperature control device, the valve, and the like, the exposure apparatus 100 need not be provided in its entirety, and at least a part thereof may be replaced with equipment such as a factory in which the exposure apparatus 100 is installed.

The liquid recovery device 6 includes a liquid tank, a suction pump, a valve for controlling recovery and stop of the liquid through the liquid recovery tube 31B, and the like. The valve is preferably the same flow control valve as the valve of the liquid supply apparatus 5. Further, the tank, suction pump, valve, and the like for recovering the liquid need not be provided in the entire exposure apparatus 100, and at least a part of the tank, suction pump, valve, and the like may be replaced with equipment such as a factory in which the exposure apparatus 100 is installed.

In the present embodiment, pure water (hereinafter, simply referred to as "water" unless otherwise specified) that is transmittable by ArF excimer laser light (light having a wavelength of 193nm) is used as the liquid. Pure water has an advantage that it can be easily obtained in a large amount in a semiconductor manufacturing factory or the like and does not adversely affect a resist, an optical lens, or the like on a wafer.

The refractive index n of water to ArF excimer laser light is approximately 1.44. In this water, the wavelength of the illumination light IL is shortened to 193nm × 1/n, which is about 134 nm.

The liquid supply device 5 and the liquid recovery device 6 each have a controller, and each controller is controlled by a main control device 20 (see fig. 6). The controller of the liquid supply apparatus 5 opens the valve connected to the liquid supply pipe 31A at a predetermined opening degree in accordance with a command from the main controller 20, and supplies water Lq between the front end lens 191 and the wafer W via the liquid supply pipe 31A, the supply flow path, and the supply port. At this time, the controller of the liquid recovery apparatus 6 opens the valve connected to the liquid recovery tube 31B at a predetermined opening degree in accordance with a command from the main controller 20, and recovers water Lq from between the front end lens 191 and the wafer W into the liquid recovery apparatus 6 (liquid tank) via the recovery port, the recovery flow path, and the liquid recovery tube 31B. At this time, the main controller 20 gives a command to the controller of the liquid supply device 5 and the controller of the liquid recovery device 6 so that the amount of water Lq supplied between the front end lens 191 and the wafer W is constantly equal to the amount of water Lq recovered. Accordingly, a certain amount of water Lq (see fig. 1) is held between the front end lens 191 and the wafer W. At this time, the water Lq held between the front end lens 191 and the wafer W is replaced as needed.

As is clear from the above description, the local immersion device 8 of the present embodiment includes the nozzle unit 32, the liquid supply device 5, the liquid recovery device 6, the liquid supply tube 31A, the liquid recovery tube 31B, and the like. The local immersion device 8 fills the space between the front end lens 191 and the wafer W with the liquid Lq through the nozzle unit 32 to form a local immersion space (corresponding to the immersion area 14) including an optical path space. Therefore, the nozzle unit 32 is also referred to as a liquid immersion space forming member or a relationship member (relationship member) or the like. Further, a part of the local immersion unit 8, for example, at least the nozzle unit 32 may be suspended and supported by a main frame (including the lens barrel holder) for holding the projection unit PU, or may be provided on a frame member different from the main frame. Alternatively, when the projection unit PU is suspended and supported as described above, the projection unit PU and the nozzle unit 32 may be suspended and supported integrally, but in the present embodiment, the nozzle unit 32 is provided in a measurement frame suspended and supported independently of the projection unit PU. In this case, the projection unit PU may not be suspended and supported.

Even when measurement stage MST is positioned below projection unit PU, a space between the measurement stage and front end lens 191, which will be described later, can be filled with water in the same manner as described above.

In the above description, as an example, one liquid supply tube (nozzle) and one liquid recovery tube (nozzle) are provided, respectively, but the present invention is not limited to this, and a configuration having a plurality of nozzles as disclosed in, for example, pamphlet of international publication No. 99/49504 may be adopted as long as the arrangement is possible in consideration of the relationship with the surrounding members. Further, for example, the lower surface of the nozzle unit 32 may be disposed closer to the image plane (that is, the wafer) of the projection optical system PL than the emission surface of the front end lens 191, or the optical path space on the object plane side of the front end lens 191 may be filled with the liquid in addition to the optical path on the image plane side of the front end lens 191. That is, the configuration may be any as long as it can supply at least the liquid to the configuration between the optical member (tip lens) 191 constituting the lowermost end of the projection optical system PL and the wafer W. For example, the exposure apparatus of the present embodiment can be applied to a liquid immersion mechanism disclosed in pamphlet of international publication No. 2004/053955, a liquid immersion mechanism disclosed in european patent publication No. 1420298, and the like.

Returning to fig. 1, the stage device 50 includes; a wafer stage WST and a measurement stage MST disposed above the base 12; interferometer system 118 (see fig. 6) including Y interferometers 16 and 18 for measuring positional information of stages WST and MST; an encoder system described later for measuring positional information of wafer stage WST at the time of exposure or the like; and a stage drive system 124 (see fig. 6) for driving stages WST, MST, and the like.

Non-contact bearings (not shown), for example, vacuum preload type aerostatic bearings (hereinafter referred to as "air pads") are provided at a plurality of positions on the bottom surfaces of wafer stage WST and measurement stage MST, respectively. The wafer stage WST and the measurement stage MST are supported in a non-contact manner above the base 12 via a gap of about several μm by the static pressure of the pressurized air ejected from these air pads onto the upper surface of the base 12. Further, stages WST and MST can be independently driven in two-dimensional directions of a Y-axis direction (left-right direction in the paper surface of fig. 1) and an X-axis direction (orthogonal direction to the paper surface of fig. 1) in a predetermined plane (XY plane) by stage driving system 124.

More specifically, as shown in the plan view of fig. 2, on the bottom surface, a pair of Y-axis fixing members 86,87 extending in the Y-axis direction are disposed on one side and the other side in the X-axis direction, respectively, with the base 12 interposed therebetween. The Y-axis fixtures 86,87 are constituted by, for example, magnetic pole units in which permanent magnet groups constituted by a plurality of sets of N-pole magnets and S-pole magnets alternately arranged at predetermined intervals in the Y-axis direction are built. In the Y-axis fixing members 86,87, the two Y-axis movable members 82,84 and 83,85 are respectively provided in a non-contact engagement state. That is, the total of four Y-axis movable members 82,84,83,85 are inserted into the inner space of the Y-axis fixture 86 or 87 having the U-shaped XZ cross section, and are supported by the corresponding Y-axis fixture 86 or 87 in a noncontact manner via an air cushion, not shown, for example, via a gap of several μm. Each of the Y-axis movers 82,84,83,85 is constituted by, for example, an armature unit in which armature coils are arranged at a predetermined interval in the Y-axis direction. That is, in the present embodiment, the Y-axis linear motors of the moving coil type are constituted by the Y-axis movable elements 82 and 84 constituted by the armature unit units and the Y-axis fixed element 86 constituted by the magnetic pole unit. Similarly, the Y-axis linear motors of the moving coil type are constituted by the Y-axis movable members 83 and 85 and the Y-axis fixed member 87, respectively. Hereinafter, the four Y-axis linear motors are referred to as a Y-axis linear motor 82, a Y-axis linear motor 84, a Y-axis linear motor 83, and a Y-axis linear motor 85, as appropriate, using the same reference numerals as those of the movable members 82,84,83, and 85, respectively.

Of the four Y-axis linear motors, the movable members 82 and 83 of the two Y-axis linear motors 82 and 83 are fixed to one end and the other end in the longitudinal direction of the X-axis fixing member 80 extending in the X-axis direction, respectively. The movable members 84,85 of the remaining two Y-axis linear motors 84,85 are fixed to one end and the other end of the X-axis fixing member 81 extending in the X-axis direction. Accordingly, the X-axis mounts 80,81 can be driven along the Y-axis by a pair of Y-axis linear motors 82,83,84,85, respectively.

Each of the X-axis anchors 80,81 is composed of, for example, an armature unit in which armature coils are installed at a predetermined interval in the X-axis direction.

An X-axis fixing member 81 is inserted into an opening (not shown) formed in a stage main body 91 (not shown in fig. 2, see fig. 1) that constitutes a part of wafer stage WST. Inside the opening of the stage main body 91, for example, a magnetic pole unit having a permanent magnet group composed of a plurality of sets of N-pole magnets and S-pole magnets alternately arranged at predetermined intervals in the X-axis direction is provided. A moving magnet X-axis linear motor for driving stage main body 91 in the X-axis direction is configured by the magnetic pole unit and the X-axis fixing member. Similarly, the other X-axis fixing member 80 is provided in an inserted state in an unillustrated opening formed in a stage main body 92 (not illustrated in fig. 2, see fig. 1) constituting the measurement stage MST. Inside the opening of the stage main body 92, a magnetic pole unit similar to that of the stage main body 91 on the wafer stage WST side) is provided. The magnetic pole unit and the X-axis fixing unit 80 constitute a moving magnet type X-axis linear motor for driving the measurement stage MST in the X-axis direction.

In the present embodiment, each of the linear motors constituting stage drive system 124 is controlled by main control device 20 shown in fig. 8. The linear motors are not limited to either of the moving magnet type and the moving coil type, and can be appropriately selected as needed.

By slightly changing the thrust forces generated by the pair of Y-axis linear motors 84 and 85, the deflection (rotation in the direction of θ z) of wafer stage WST can be controlled. Further, by slightly changing the thrust forces generated by the pair of Y-axis linear motors 82 and 83, the deflection of the measurement stage MST can be controlled.

Wafer stage WST includes: the stage body 91; and a wafer table WTB mounted on stage body 91. Wafer table WTB and stage main body 91 are finely driven in the Z-axis direction, the θ X direction, and the θ Z direction with respect to base 12 and X-axis fixing member 81 by a Z leveling mechanism (including, for example, a voice coil motor) not shown. That is, wafer table WTB can be slightly moved in the Z-axis direction or tilted with respect to the XY plane (or the image plane of projection optical system PL). In fig. 6, the linear motors and the Z leveling mechanism described above are shown together with a drive system for measurement stage MST as stage drive system 124. Further, wafer table WTB may be configured to be capable of fine movement in at least one of the X-axis, Y-axis, and θ z-direction.

The wafer table WTB is provided with a wafer holder (not shown) for holding the wafer W by vacuum suction or the like. Although the wafer holder may be formed integrally with wafer table WTB, in the present embodiment, the wafer holder and wafer table WTB are separately formed, and the wafer holder is fixed in a recess of wafer table WTB by, for example, vacuum suction. Further, a plate (lyophobic plate) 28 having a surface (lyophobic surface) which is substantially flush with the surface of the wafer mounted on the wafer holder and has been subjected to lyophobic treatment with respect to the liquid Lq is provided on the upper surface of the wafer table WTB, and has a rectangular outer shape (outline) and a circular opening which is one turn larger than the wafer holder (wafer mounting region) is formed in the central portion thereof. The plate 28 is made of a material having a low thermal expansion coefficient, such as glass or ceramic (trade name: Zerodur, Seidel) or Al₂O₃Or TiC) and a liquid repellent film is formed on the surface of the substrate by a fluororesin material, a fluororesin material such as polytetrafluoroethylene (teflon (registered trademark)), an acrylic resin material, a silicone resin material, or the like. As shown in the plan view of wafer table WTB (wafer stage WST) in fig. 4a, plate body 28 has a 1 st lyophobic area 28a having a rectangular outer shape (outline) for surrounding a circular opening, and a 2 nd lyophobic area 28b having a rectangular frame shape (ring shape) disposed around 1 st lyophobic area 28 a. For example, at the time of exposure operation, the 1 st lyophobic region 28a is formed with at least a part of the liquid immersion region 14 extending from the wafer surface, and the 2 nd lyophobic region 28b is formed with a scale for an encoder system to be described later. At least a portion of the surface of the plate 28 may not be flush with the wafer surface, i.e., may be at a different height. Further, the plate 28 may be a single plate, but in the present embodiment, it is a plurality of plates, for example, combined and individually combinedThe 1 st and 2 nd lyophobic plates corresponding to the 1 st and 2 nd lyophobic areas 28a and 28 b. In the present embodiment, since pure water is used as the liquid Lq as described above, the 1 st and 2 nd lyophobic regions 28a and 28b are also referred to as the 1 st and 2 nd lyophobic plates 28a and 28b hereinafter.

In this case, the exposure light IL is hardly irradiated to the outer 2 nd hydrophobic plate 28b, as opposed to the 1 st hydrophobic plate 28a on which the exposure light IL is irradiated. In view of this, in the present embodiment, the 1 st hydrophobic region to which a hydrophobic coating film having sufficient resistance to the exposure light IL (in this case, light in the vacuum ultraviolet region) is applied is formed on the surface of the 1 st hydrophobic plate 28a, and the 2 nd hydrophobic region to which a hydrophobic coating film having less resistance to the exposure light IL than the 1 st hydrophobic region is applied is formed on the surface of the 2 nd hydrophobic plate 28 b. Since it is generally not easy to apply a hydrophobic coating film having sufficient resistance to the exposure light IL (in this case, light in the vacuum ultraviolet region) to the glass plate, it is more effective to separate the 1 st hydrophobic plate 28a and the 2 nd hydrophobic plate 28b around the 1 st hydrophobic plate into two parts as described above. Further, the present invention is not limited to this, and two kinds of hydrophobic coating films having different resistances to the exposure light IL may be applied to the upper surface of the same plate body to form the 1 st hydrophobic region and the 2 nd hydrophobic region. The kind of the hydrophobic coating film in the 1 st and 2 nd hydrophobic regions may be the same. Or, for example, only one hydrophobic region may be formed in the same plate body.

As is clear from fig. 4a, a rectangular notch is formed in the center portion in the X axis direction of the + Y side end portion of the 1 st hydrophobic plate 28a, and the measurement plate 30 is embedded in a rectangular space (inside the notch) surrounded by the notch and the 2 nd hydrophobic plate 28 b. A reference mark FM is formed at the center in the longitudinal direction of measurement plate 30 (on center line LL of wafer table WTB), and a pair of aerial image measurement slit patterns SL are formed on one side and the other side of the reference mark in the X-axis direction, symmetrically arranged with respect to the center of the reference mark. For each aerial image measurement slit pattern SL, for example, an L-shaped slit pattern having sides extending in the Y-axis direction and the X-axis direction is used.

As shown in fig. 4B, L-shaped frame 36 having an optical system (including an objective lens, a mirror, a relay lens, and the like) housed therein is attached to wafer stage WST in a state where it penetrates a part of the inside of stage main body 91 from wafer stage WTB and is partially embedded in a portion of wafer stage WST below each aerial image measuring slit pattern SL. Although not shown, a pair of frames 36 is provided corresponding to the pair of aerial image measurement slit patterns SL.

The optical system inside the housing 36 guides the illumination light IL, which has passed through the aerial image measuring slit pattern SL from above to below, along an L-shaped path, and emits the illumination light IL in the-Y direction. For convenience of description, the optical system inside the housing 36 is described as the light transmission system 36 using the same reference numeral as that of the housing 36.

Further, a plurality of grid lines are directly formed on the upper surface of the 2 nd hydrophobic plate 28b at predetermined pitches along the four sides thereof. More specifically, a Y scale 39Y is formed in each of the regions on one side and the other side (left and right sides in fig. 4 a) of the 2 nd hydrophobic plate 28b in the X axis direction₁,39Y₂. Y scale 39Y₁,39Y₂For example, the grid lines 38 having the X-axis direction as the longitudinal direction are formed at a predetermined pitch in a direction (Y-axis direction) parallel to the Y-axis, and are formed as a reflection type grid (for example, a diffraction grating) having the Y-axis direction as the periodic direction.

Similarly, an X scale 39X is formed in each of the regions on one side and the other side (upper and lower sides in fig. 4 a) of the 2 nd hydrophobic plate 28b in the Y axis direction₁,39X₂X scale 39X₁,39X₂For example, the grid lines 37 having the Y-axis direction as the longitudinal direction are formed at a predetermined pitch in a direction parallel to the X-axis (X-axis direction), and are formed of a reflection type grid (for example, diffraction grating) having the X-axis direction as the periodic direction. Each scale is formed as a reflection type diffraction grating RG on the surface of the 2 nd hydrophobic plate 28b by, for example, a hologram (fig. 8 a). In this case, a grid of narrow slits, grooves, or the like is formed as a scale at predetermined intervals (pitches) on each scale. The type of diffraction grating used for each scale is not limited, and the diffraction grating may be formed not only by mechanically forming grooves or the like, but also by sintering interference patterns on the photosensitive materialA resin is used. Each scale is formed by, for example, scribing the scale of the diffraction grating on a thin plate glass at a pitch of 138nm to 4 μm (for example, 1 μm pitch). These scales are covered with the aforementioned lyophobic film (hydrophobic film). In fig. 4(a), for convenience of illustration, the pitch of the grating is illustrated to be much larger than the actual pitch. This is the same in other figures.

In this way, in the present embodiment, since the 2 nd hydrophobic plate 28b itself is configured as a scale, a glass plate having low thermal expansion is used as the 2 nd hydrophobic plate 28 b. However, the scale member may be fixed to the upper surface of the wafer table WTB by, for example, a plate spring (or vacuum suction) so as to avoid local expansion and contraction, and in this case, a hydrophobic plate having the same hydrophobic coating film applied to the entire surface may be used as the plate member 28. Alternatively, wafer table WTB may be formed of a material having a low thermal expansion coefficient, and in this case, the pair of Y scales and the pair of X scales may be formed directly on wafer table WTB.

the-Y end face and the-X end face of wafer table WTB are mirror-finished to form a reflection surface 17a and a reflection surface 17b shown in FIG. 2, respectively. Y interferometer 16 and X interferometer 126,127,128 (X interferometers 126 to 128 are not shown in fig. 1, see fig. 2) constituting a part of interferometer system 118 (see fig. 6) project interferometer beams (ranging beams) onto reflection surfaces 17a and 17b, respectively, and receive the respective reflected lights to measure a displacement of each reflection surface from a reference position (generally, a fixed mirror is disposed on a side surface of projection unit PU, and the fixed mirror is used as a reference surface), that is, positional information of wafer stage WST in the XY plane, and supply the measured values to main controller 20. In the present embodiment, as described later, a multi-axis interferometer having a plurality of lateral and longitudinal axes is used as each interferometer except for a part thereof.

On the other hand, as shown in fig. 1 and 4(B), a movable mirror 41 whose longitudinal direction is the X-axis direction is attached to the-Y-side end surface of the stage main body 91 via a dynamic support mechanism (not shown).

A pair of interferometers 43A and 43B (see fig. 1 and 2) constituting a part of an interferometer system 118 (see fig. 6) for irradiating a distance measuring beam to the movable mirror 41 are provided so as to face the movable mirror 41. More specifically, as is apparent from fig. 2 and 4(B) taken together, the length of movable mirror 41 in the X axis direction is designed to be longer than reflection surface 17a of wafer table WTB by at least the distance between Z interferometers 43A and 43B. The movable mirror 41 is formed of a member having a hexagonal cross-sectional shape in which a rectangular shape and an equiangular trapezoid are integrated. The surface of the movable mirror 41-Y side is mirror-finished to form three reflecting surfaces 41b,41a,41 c.

The reflection surface 41a constitutes a-Y side end surface of the moving mirror 41, and extends in the X-axis direction in parallel with the XZ plane. The reflection surface 41B is a surface adjacent to the + Z side of the reflection surface 41a, and extends in the X-axis direction in parallel with a surface inclined at a predetermined angle in the clockwise direction of fig. 4(B) with respect to the XZ plane. The reflection surface 41c is a surface adjacent to the-Z side of the reflection surface 41a, and is provided symmetrically with respect to the reflection surface 41b with the reflection surface 41a interposed therebetween.

As is clear from fig. 1 and 2, Z interferometers 43A and 43B are separated from one another by substantially the same distance in the X-axis direction of Y interferometer 16 and are disposed at positions slightly lower than Y interferometer 16.

As shown in fig. 1, the distance measuring beam B1 in the Y-axis direction is projected from the Z interferometers 43A and 43B to the reflection surface 41B, and the distance measuring beam B2 in the Y-axis direction is projected to the reflection surface 41c (see fig. 4B). In the present embodiment, the fixed mirror 47A having a reflection surface orthogonal to the distance measuring beam B1 reflected by the reflection surface 41B and the fixed mirror 47B having a reflection surface orthogonal to the distance measuring beam B2 reflected by the reflection surface 41c are extended in the X-axis direction at positions separated by a predetermined distance from the movable mirror 41 in the-Y direction without interfering with the distance measuring beams B1 and B2, respectively.

The fixed mirrors 47A and 47B are supported by the same support body (not shown) provided in a frame (not shown) for supporting the projection unit PU, for example. The fixed mirrors 47A and 47B may be provided on the measurement frame. In the present embodiment, the movable mirror 41 having the three reflection surfaces 41B,41a, and 41c and the fixed mirrors 47A and 47B are provided, but the present invention is not limited to this, and a movable mirror having a 45-degree slope may be provided on the side surface of the stage main body 91, and the fixed mirror may be disposed above the wafer stage WST. In this case, the fixed mirror may be provided on the support, the measurement frame, or the like.

As shown in FIG. 2, the Y interferometer 16 separates a distance measuring beam B4 from a straight line parallel to the Y axis passing through the projection center (optical axis AX, see FIG. 1) of the projection optical system PL along the Y axis direction distance measuring axis which is separated by the same distance on the-X side and the + X side₁,B4₂Projected on reflection surface 17a of wafer table WTB, and then receives the respective reflected lights to detect distance measuring beam B4 of wafer table WTB₁,B4₂The position in the Y-axis direction (Y position) of the irradiation point. In addition, the distance measuring beam B4 is representatively shown in FIG. 1₁,B4₂Shown as ranging beam B4.

In addition, Y interferometer 16 is at range beam B4₁,B4₂The Y position of reflecting surface 41a of movable mirror 41 (that is, wafer stage WST) is detected by projecting distance measuring beam B3 along the Y-axis distance measuring axis toward reflecting surface 41a with a predetermined distance therebetween in the Z-axis direction, and receiving distance measuring beam B3 reflected by reflecting surface 41 a.

Master control device 20 correlates the distance measuring beam B4 with Y interferometer 16₁,B4₂The Y position (more precisely, the displacement Δ Y in the Y axis direction) of wafer table WTB (wafer stage WST), which is reflection surface 17a, is calculated from the average of the measurement values of the corresponding distance measurement axes. In addition, master control device 20 slave-to-ranging beam B4₁,B4₂The displacement (deflection amount) Delta theta Z of the wafer table WTB in the rotation direction (theta Z) around the Z axis is calculated according to the measurement value difference of the distance measurement axis^(Y). Further, main controller 20 calculates a displacement (pitch) Δ θ x of wafer stage WST in the θ x direction from the Y position (displacement Δ Y in the Y axis direction) of reflection surface 17a and reflection surface 41 a.

Further, as shown in fig. 2, the X interferometer 126 measures a distance measuring beam B5 along a biaxial distance measuring axis having the same distance from a straight line LH passing through the optical axis of the projection optical system PL in the X-axis direction₁,B5₂Projected on wafer table WTB, main control device 20, based on distance measuring beam B5₁,B5₂The position of wafer table WTB in the X-axis direction (X position, more precisely, displacement Δ X in the X-axis direction) is calculated from the measured value of the corresponding distance measurement axis. In addition, master control device 20 slave-to-ranging beam B5₁,B5₂The displacement (deflection) of the wafer table WTB in the theta z direction is calculated by the measurement value difference of the corresponding distance measuring axis^(X). In addition, Δ θ z obtained from the X interferometer 126^(X)With Δ θ z obtained from the Y interferometer 16^(Y)Equal to each other, and represents a displacement (deflection amount) Δ θ z of wafer table WTB in the θ z direction.

In addition, as shown by the broken line in fig. 2, a ranging beam B7 is emitted from the X interferometer 128 along a ranging axis parallel to the X axis. X interferometer 128 projects measuring beam B7 on reflection surface 17B of wafer table WTB located in the vicinity of unloading position UP and loading position LP along a measuring axis substantially parallel to the X axis connecting unloading position UP and loading position LP (see fig. 3) to be described later. Further, as shown in fig. 2, ranging beam B6 from X interferometer 127 is projected to reflection surface 17B of wafer table WTB. In practice, range beam B6 is projected onto reflective surface 17B of wafer table WTB along a range axis parallel to the X-axis of the center of detection by alignment system AL 1.

Main controller 20 may also determine displacement Δ X of wafer table WTB in the X-axis direction from the measurement value of distance measuring beam B6 of X interferometer 127 and the measurement value of distance measuring beam B7 of X interferometer 128. However, the three X interferometers 126,127,128 are arranged differently in the Y-axis direction, and the X interferometer 126 is used for exposure shown in fig. 18, the X interferometer 127 is used for wafer alignment shown in fig. 25 and the like, and the X interferometer 128 is used for wafer loading shown in fig. 22 and 23 and unloading shown in fig. 21.

Further, the distance measuring beams B1 and B2 along the Y axis are projected from the Z interferometers 43A and 43B to the moving mirror 41. These distance measuring beams B1, B2 enter the reflection surfaces 41B,41c of the movable mirror 41 at a predetermined incident angle (θ/2). The distance measuring beams B1 and B2 are reflected by the reflection surfaces 41B and 41c, respectively, and enter the reflection surfaces of the fixed mirrors 47A and 47B perpendicularly. Then, the distance measuring beams B1, B2 reflected by the reflection surfaces of the fixed mirrors 47A,47B are reflected by the reflection surfaces 41B,41c (returned back to the optical path upon incidence) and received by the Z interferometers 43A, 43B.

Here, when the displacement of wafer stage WST (i.e., movable mirror 41) in the Y axis direction is Δ Yo and the displacement in the Z axis direction is Δ Zo, the optical path length change Δ L1 of distance measuring beam B1 and the optical path length change Δ L2 of distance measuring beam B2, which are received by Z interferometers 43A and 43B, can be expressed by the following expressions (1) and (2), respectively.

ΔL1＝ΔYo×(1+cosθ)－ΔZo×sinθ…(1)

ΔL2＝ΔYo×(1+cosθ)+ΔZo×sinθ…(2)

Therefore, from the expressions (1), (2), Δ Yo and Δ Zo, the following expressions (3) and (4) can be obtained.

ΔZo＝(ΔL2－ΔL1)/2sinθ…(3)

ΔYo＝(ΔL1+ΔL2)/{2(1+cosθ)}…(4)

The shifts Δ Zo and Δ Yo are obtained by the Z interferometers 43A and 43B, respectively. Therefore, the shifts obtained by Z interferometer 43A are denoted as Δ ZoR and Δ YoR, and the shifts obtained by Z interferometer 43B are denoted as Δ ZoL and Δ YoL. Next, the distance separating the distance measuring beams B1, B2 projected by the Z interferometers 43A,43B in the X-axis direction is denoted by D (see fig. 2). Under the above-described premise, the displacement (amount of deflection) Δ θ z of the movable mirror 41 (i.e., the wafer stage WST) in the θ z direction and the displacement (amount of deflection) Δ θ y of the movable mirror 41 (i.e., the wafer stage WST) in the θ y direction can be obtained by the following expressions (5) and (6).

Δθz≒(ΔYoR－ΔYoL)/D…(5)

Δθy≒(ΔZoL－ΔZoR)/D…(6)

Therefore, main controller 20 can calculate the four-degree-of-freedom displacements Δ Zo, Δ Yo, Δ θ Z, and Δ θ y of wafer stage WST from the measurement results of Z interferometers 43A and 43B by using equations (3) to (6).

In this way, main controller 20 can calculate the displacement of wafer stage WST in the six-degree-of-freedom direction (Z, X, Y, Δ θ Z, Δ θ X, Δ θ Y direction) from the measurement result of interferometer system 118. In the present embodiment, interferometer system 118 can measure positional information of wafer stage WST in the direction of six degrees of freedom, but the measurement direction is not limited to the direction of six degrees of freedom, and may be a direction of five degrees of freedom or less.

In the present embodiment, a single stage in which wafer stage WST (91, WTB) is movable in six degrees of freedom has been described, but this is not limitative, and wafer stage WST may be configured to include a stage main body 91 movable in the XY plane, and a wafer stage WTB mounted on stage main body 91 and capable of being slightly driven in at least the Z-axis direction, the θ x direction, and the θ y direction with respect to stage main body 91. In this case, the moving mirror 41 is provided on the wafer table WTB. Instead of the reflection surface 17a and the reflection surface 17b, a movable mirror formed of a flat mirror may be provided on the wafer table WTB.

However, in the present embodiment, the positional information of wafer stage WST (wafer table WTB) in the XY plane (positional information in the three-degree-of-freedom direction including the rotation information in the θ z direction) is mainly measured by an encoder system described later, and the measurement value of interferometer 16,126,127 is used for the purpose of assisting in correcting (correcting) long-term fluctuation of the measurement value of the encoder system (for example, due to change of a scale with time or the like) and for backup when an output abnormality of the encoder occurs. In the present embodiment, the positional information of the six-degree-of-freedom directions of wafer stage WST, including the X-axis direction, the Y-axis direction, and the θ Z direction, is measured by an encoder system described below, and the positional information of the remaining three-degree-of-freedom directions, that is, the Z-axis direction, the θ X direction, and the θ Y direction, is measured by a measurement system having a plurality of Z sensors described below. Here, the remaining three degrees of freedom can also be measured by both the measurement system and the interferometer system 18. For example, the position information in the Z-axis direction and the θ y direction may be measured by the measurement system, and the position information in the θ x direction may be measured by the interferometer system 118.

At least a part of the interferometer system 118 (for example, an optical system or the like) may be provided on a main frame for holding the projection unit PU or may be provided integrally with the projection unit PU suspended and supported as described above.

The measurement stage MST includes the stage main body 92 and a measurement table MTB mounted on the stage main body 92. The measurement table MTB is also mounted on the stage body 92 via a Z leveling mechanism not shown. However, the present invention is not limited to this, and a measurement stage MST having a so-called coarse fine movement structure in which measurement table MTB can be finely moved with respect to stage main body 92 in the X-axis direction, the Y-axis direction, and the θ z direction may be employed, or measurement stage MST may be fixed to stage main body 92, and the entire measurement stage MST including measurement table MTB and stage main body 92 may be configured to be drivable in the six-degree-of-freedom direction.

Various measuring members are provided on measuring table MTB (and stage main body 92). As the measuring means, for example, as shown in fig. 2 and 5a, an uneven illuminance sensor 94 having a pinhole-shaped light receiving unit for receiving illumination light IL on an image plane of the projection optical system PL, an aerial image measuring instrument 96 for measuring an aerial image (projection image) of a pattern projected by the projection optical system PL, a Shack-Hartman type wavefront aberration measuring instrument 98 disclosed in, for example, international publication No. 03/065428 pamphlet, and the like are used. The wavefront aberration sensor 98 can be used, for example, as disclosed in international publication No. 99/60361 pamphlet (corresponding to european patent No. 1,079,223).

The uneven illuminance sensor 94 can have the same structure as disclosed in, for example, japanese patent laid-open No. 57-117238 (corresponding to U.S. Pat. No. 4,465,368). The aerial image measuring instrument 96 can be constructed in the same manner as disclosed in, for example, japanese patent application laid-open No. 2002-14005 (corresponding to U.S. patent application publication No. 2002/0041377). In the present embodiment, three measuring members (94,96,98) are provided on measurement stage MST, but the type, number, and the like of the measuring members are not limited to these. As the measuring means, for example, a transmittance measuring instrument for measuring the transmittance of the projection optical system PL, a measuring instrument for observing the local immersion device 8, for example, the nozzle unit 32 (or the distal end lens 191), or the like can be used. Further, a member different from the measuring member, for example, a cleaning member for cleaning the nozzle unit 32, the tip lens 191, and the like may be mounted on the measurement stage MST.

In the present embodiment, as can be seen from fig. 5a, the sensors having a high frequency of use, uneven illuminance sensor 94, aerial image measuring instrument 96, and the like are disposed on center line CL (Y axis passing through the center) of measurement stage MST. Therefore, in the present embodiment, the measurement using these sensors is performed not by moving measurement stage MST in the X-axis direction but only by moving it in the Y-axis direction.

In addition to the above-described sensors, an illuminance monitor having a light receiving section of a predetermined area for receiving the illumination light IL on the image plane of the projection optical system PL, such as disclosed in japanese patent application laid-open No. 11-16816 (corresponding to U.S. patent application publication No. 2002/0061469), can be used, and the illuminance monitor is preferably arranged on the center line.

In the present embodiment, in response to the immersion exposure performed to expose the wafer W with the exposure light (illumination light) IL via the projection optical system PL and the liquid (water) Lq, the illumination light IL is received via the projection optical system PL and water from the uneven illuminance sensor 94 (and the illuminance monitor), the aerial image measuring device 96, and the wavefront aberration sensor 98 used for measurement using the illumination light IL. Each sensor may be mounted on measurement table MTB (and stage main body 92) only in part of the optical system and the like, or the entire sensor may be disposed on measurement table MTB (and stage main body 92), for example.

As shown in fig. 5(B), frame-shaped mounting member 42 is fixed to a-Y-side end surface of stage main body 92 of measurement stage MST. Further, a pair of light receiving systems 44 are fixed to the-Y-side end surface of stage body 92 in the vicinity of the center position in the X-axis direction inside the opening of mounting member 42 so as to be opposed to the pair of light transmitting systems 36. Each light receiving system 44 is configured by an optical system such as a relay lens, a light receiving element (for example, a photomultiplier tube), and a housing that houses these components. As is clear from fig. 4(B) and 5(B) and the description up to now, in the present embodiment, in a state (including a contact state) in which wafer stage WST and measurement stage MST are within a predetermined distance in the Y-axis direction, illumination light IL transmitted through each aerial image measurement slit pattern SL of measurement plate 30 is guided by each light transmitting system 36 and received by a light receiving element inside each light receiving system 44. That is, the measurement plate 30, the light transmitting system 36, and the light receiving system 44 constitute an aerial image measuring apparatus 45 (see fig. 6) similar to that disclosed in the aforementioned japanese patent application laid-open No. 2002-14005 (corresponding to the specification of U.S. patent application publication No. 2002/0041377) and the like.

A reference bar (hereinafter, simply referred to as "CD bar") as a reference member made of a bar-shaped member having a rectangular cross section is provided to extend in the X-axis direction on the mounting member 42. The CD bar 46 is dynamically supported on the measurement stage MST by a fully dynamic frame structure.

Since the CD bar 46 is a standard (measurement standard), an optical glass ceramic having a low thermal expansion coefficient, for example, Zerodur (trade name) of seidel corporation, or the like is used as a material. The flatness of the upper surface (surface) of the CD bar 46 is set high to the same degree as that of a so-called reference plane plate. As shown in fig. 5a, reference grids (e.g., diffraction gratings) 52 having a periodic direction in the Y-axis direction are formed near one end and the other end of the CD bar 46 in the longitudinal direction. The pair of reference grids 52 are formed so as to be arranged symmetrically with respect to the center of the CD bar 46 in the X-axis direction, i.e., with respect to the center line CL, with a predetermined distance (L) therebetween.

Further, a plurality of reference marks M are formed on the upper surface of the CD bar 46 in the arrangement shown in fig. 5 (a). The plurality of reference marks M are arranged in three rows in the Y-axis direction at the same pitch, and the rows are arranged to be offset from each other by a predetermined distance in the X-axis direction. Each reference mark M is, for example, a two-dimensional mark having a size detectable by a primary alignment system or a secondary alignment system described later. The shape (configuration) of the fiducial marks M may be different from that of the fiducial marks FM, but in the present embodiment, the fiducial marks M are configured in the same manner as the fiducial marks FM, and are also configured in the same manner as the alignment marks of the wafer W. In the present embodiment, the surface of the CD bar 46 and the surface of the measuring table MTB (which may include the measuring member) are each covered with a liquid repellent film (water repellent film).

Reflection surfaces 19a and 19b (see fig. 2 and 5 a) similar to wafer table WTB are also formed on the + Y end surface and the-X end surface of measurement table MTB. Y interferometer 18 and X interferometer 130 (X interferometer 130 is not shown in fig. 1, see fig. 2) of interferometer system 118 (see fig. 6), as shown in fig. 2, project interferometer beams (ranging beams) onto reflection surfaces 19a and 19b, respectively, and receive the respective reflected lights, thereby measuring the displacement of the respective reflection surfaces from the reference position, that is, the positional information of measurement stage MST (including, for example, positional information in the X-axis and Y-axis directions and rotational information in the θ z direction), and supplying the measured values to main control device 120.

Although the exposure apparatus 100 of the present embodiment is omitted in fig. 1 in order to avoid an excessively complicated drawing, in actuality, as shown in fig. 3, a primary alignment system AL1 is arranged, and this primary alignment system AL1 has a detection center at a position spaced apart by a predetermined distance from the optical axis to the-Y side on a straight line LV passing through the center of the projection unit PU (coinciding with the optical axis AX of the projection optical system PL, and also coinciding with the center of the exposure area IA in the present embodiment) and parallel to the Y axis. This primary alignment system AL1 is secured to the underside of a main frame, not shown, via support members 54. On one side and the other side in the X axis direction of this primary alignment system AL1, a secondary (secondary) alignment system AL2 is provided, the detection centers of which are arranged substantially symmetrically with respect to the straight line LV₁,AL2₂And AL2₃,AL2₄. That is, five alignment systems AL1, AL2₁～AL2₄The detection centers of (b) are arranged at different positions in the X-axis direction, that is, arranged along the X-axis direction.

Each secondary alignment system AL2_n(n-1-4), as representatively shownQuasi-system AL2₄In this way, the arm 56 fixed to the arm can rotate in the clockwise and counterclockwise directions in fig. 3 by a predetermined angle range around the rotation center O_n(n is 1 to 4) leading ends (turning ends). In the present embodiment, each secondary alignment system AL2_nIs fixed to the arm 56 (e.g., an optical system including at least a light guide for guiding light generated by an object mark in the detection area to a light receiving element) and irradiates the detection area with alignment light_nThe remaining part is disposed in a main frame for holding the projection unit PU. Secondary alignment system AL2₁,AL2₂,AL2₃,AL2₄The X position can be adjusted by rotating about the rotation center O, respectively. That is, the secondary alignment system AL2₁,AL2₂,AL2₃,AL2₄The detection area (or the detection center) of (a) can be independently moved in the X-axis direction. Thus, primary alignment system AL1 and secondary alignment system AL2₁,AL2₂,AL2₃,AL2₄The relative position of the detection area in the X-axis direction can be adjusted. In the present embodiment, the secondary alignment system AL2 is adjusted by rotating the arm₁,AL2₂,AL2₃,AL2₄But not limited thereto, a secondary alignment system AL2 may be provided₁,AL2₂,AL2₃,AL2₄And a driving mechanism for driving the X-axis direction in a reciprocating manner. In addition, secondary alignment system AL2₁,AL2₂,AL2₃,AL2₄May be movable not only in the X-axis direction but also in the Y-axis direction. In addition, each secondary alignment system AL2_nIs passed through the arm 56_nSo that it can be measured by a sensor not shown, such as an interferometer or encoder, etc., fixed to the arm 56_nA part of the location information. This sensor may measure only the secondary alignment system AL2_nThe position information in the X-axis direction can be measured in other directions such as the Y-axis direction and/or the rotational direction (including at least one of the θ X and θ Y directions).

At each arm 56_nOn the upper surface, a vacuum pad 58 composed of a differential exhaust type air bearing is provided_n(n is 1 to 4). In addition, the arm 56_nFor example by a rotary drive mechanism 60 comprising a motor or the like_n(n is 1 to 4, not shown in fig. 3, refer to fig. 6), and is rotatable in accordance with an instruction from the main control device 20. Main control device 20 is on arm 56_nAfter the rotation adjustment, the vacuum pads 58 are adjusted_nAct to move each arm 56_nIs fixed by suction to a main frame not shown. Thus, each arm 56 can be maintained_nThe post-rotation state of (1), i.e., maintaining 4 secondary alignment systems AL2 relative to the primary alignment system AL1₁～AL2₄A desired positional relationship.

In addition, the arms 56 with the main frame_nThe facing portion may be made of a magnetic material, and an electromagnet may be used instead of the vacuum pad 58.

The primary alignment system AL1 and the 4 secondary alignment systems AL2 of the present embodiment₁～AL2₄For example, a Field Image Alignment (FIA) system of an Image processing system may be used, which irradiates a target mark with a wide-band detection light beam that does not expose a resist on a wafer, and captures an Image of the target mark imaged on a light receiving surface by reflected light from the target mark and an Image of a pointer (pointer pattern on a pointer plate provided in each Alignment system), not shown, with an imaging device (CCD (charge coupled device) or the like), and outputs imaging signals of these. From primary alignment system AL1 and 4 secondary alignment systems AL2₁～AL2₄The respective image pickup signals are supplied to the main controller 20 of fig. 6.

Note that the alignment systems are not limited to the FIA system, and it is needless to say that an alignment sensor capable of detecting scattered light or diffracted light generated from a target mark by irradiating coherent detection light to the target mark, or an alignment sensor capable of detecting two diffracted lights (for example, diffracted light of the same order or diffracted light in the same direction) generated from the target mark by interference may be used alone or in an appropriate combination. In the present embodiment, five alignment systems AL1 and AL2 are provided₁～AL2₄However, the number is not limited to five, and two or more and four or more may be usedNext, six or more may be used, or an even number may be used instead of the odd number. Furthermore, in the present embodiment, five alignment systems AL1 and AL2 are provided₁～AL2₄The projection unit PU is fixed to the lower surface of the main frame for holding the projection unit PU via the support member 54, but the present invention is not limited thereto, and may be provided to the measurement frame. In addition, alignment systems AL1, AL2₁～AL2₄Since the alignment mark of the wafer W and the reference mark of the CD bar 46 are detected, they may be referred to as a mark detection system in the present embodiment.

As shown in fig. 3, the exposure apparatus 100 of the present embodiment has four head units 62A to 62D of an encoder system arranged so as to surround the periphery of the nozzle unit 32 from four directions. Although these head units 62A to 62D are omitted in fig. 3 and the like in order to avoid an excessively complicated drawing, they are actually fixed in a suspended state to a main frame for holding the projection unit PU via a support member. For example, when the projection unit PU is suspended, the head units 62A to 62D may be suspended and supported integrally with the projection unit PU or may be provided on the measurement frame.

The head units 62A and 62C are arranged on the + X side and the-X side of the projection unit PU, respectively, with the X-axis direction as the longitudinal direction, and are arranged at substantially the same distance from the optical axis AX with respect to the optical axis AX of the projection optical system PL. The head units 62B and 62D are disposed on the + Y side and the-Y side of the projection unit PU, respectively, with the Y-axis direction being the longitudinal direction and at substantially the same distance from the optical axis AX with respect to the optical axis AX of the projection optical system PL.

As shown in fig. 3, the head units 62A,62C include a plurality of (six in this case) Y heads 64 arranged at predetermined intervals on a straight line LH passing through the optical axis AX of the projection optical system PL and parallel to the X axis. A head unit 62A configured to use the Y scale 39Y₁Y linear encoder (hereinafter, referred to as "Y encoder" or "encoder" as appropriate) 70A (see fig. 6) for measuring the position (Y position) of wafer stage WST (wafer table WTB) in the Y axis direction for a plurality of eyes (here, six eyes). Similarly, the head unit 62C is configured using the Y scale 39Y₂To measure a wafer carrierY encoder 70C (see fig. 6) for multiple eyes (six eyes here) of WST (Y position of wafer table WTB). Here, the distance between adjacent Y heads 64 (i.e., measuring beams) of the head units 62A and 62C is set to be larger than the distance between the Y scales 39Y and 62C₁,39Y₂The width in the X-axis direction (more precisely, the length of the grid lines 38) is narrow. Further, the Y head 64 positioned innermost among the plurality of Y heads 64 provided in each of the head units 62A and 62C is fixed to the lower end portion of the barrel 40 of the projection optical system PL (more precisely, the lateral side of the nozzle unit 32 surrounding the tip lens 191) in order to be disposed as far as possible on the optical axis of the projection optical system PL.

As shown in fig. 3, the head unit 62B includes a plurality of (here, seven) X heads 66 arranged on the straight line LV at predetermined intervals. The head unit 62D includes a plurality of X heads 66 (here, eleven heads (three not shown in fig. 3 that overlap the primary alignment system AL 1)) arranged on the straight line LV at predetermined intervals. A head unit 62B configured to use the X scale 39X₁X linear encoder (hereinafter, referred to as "X encoder" or "encoder" as appropriate) 70B for measuring the position (X position) of wafer stage WST (wafer table WTB) in the X-axis direction for a plurality of eyes (here, seven eyes) (see fig. 6). The head unit 62D is configured using the X scale 39X₂X encoder 70D (see fig. 6) for measuring a plurality of eyes (here, eleven eyes) of X position of wafer stage WST (wafer table WTB). In the present embodiment, for example, two heads 66 out of the eleven X heads 66 included in the head unit 62D may simultaneously face the X scale 39X during alignment described later₁X scale 39X₂. At this time, the X scale 39X is passed₁An X linear encoder 70B is formed with the X head 66 facing thereto, and passes through the X scale 39X₂The X linear encoder 70D is configured with the X head 66 facing thereto.

Here, some of the eleven X heads 66, here three X heads, are mounted on the lower surface side of the support member 54 of the primary alignment system AL 1. The distance between adjacent X heads 66 (measuring beams) provided in the head units 62B and 62D is set to be greater than the X scale 39X₁,39X₂The width in the Y-axis direction (more precisely, the length of the grid lines 37) is narrow. Further, among the plurality of X heads 66 provided in each of head units 62B and 62D, the X head 66 positioned on the innermost side is fixed to the lower end portion of the barrel 40 of the projection optical system PL (more precisely, the lateral side of the nozzle unit 32 surrounding the tip lens 191) so as to be disposed on the optical axis of the projection optical system PL as much as possible.

Further, in the secondary alignment system AL2₁of-X-side, secondary alignment system AL2₄On the + Y side of the primary alignment system AL1, Y heads 64Y are provided, respectively, on a straight line parallel to the X axis passing through the detection center of the primary alignment system AL1, the detection points of which are arranged substantially symmetrically with respect to the detection center₁,64y₂. Y read head 64Y₁,64y₂Is set to be substantially equal to the distance L. Y read head 64Y₁,64y₂In the state shown in fig. 3 where the center of wafer W on wafer stage WST is positioned on line LV, the center of wafer W is aligned with Y scale 39Y₂,39Y₁Are opposite. The Y scale 39Y is used for alignment operation described later₂,39Y₁Respectively with Y head 64Y₁,64y₂Arranged in opposition to each other, and passes through the Y head 64Y₁,64y₂(i.e., by these Y read heads 64Y)₁,64y₂Y encoders 70C,70A) configured to measure the Y position (and θ z rotation) of wafer stage WST.

In the present embodiment, when the baseline measurement of the secondary alignment system, which will be described later, is performed, the pair of reference grids 52 of the CD bar 46 and the Y head 64Y₁,64y₂Respectively facing each other, passing through and facing the Y head 64Y₁,64y₂The Y position of the CD bar 46 is measured with respect to the positions of the respective reference grids 52 by the opposing reference grids 52. Hereinafter, the Y heads 64Y facing the reference grids 52 will pass₁,64y₂The encoders thus constructed are referred to as Y-axis linear encoders 70E,70F (see fig. 6).

The six linear encoders 70A to 70E measure positional information in the measurement direction of each wafer stage WST with a resolution of, for example, about 0.1nm, and the measured values (measurement information) of these are supplied to main controller 20, and main controller 20 controls the position of wafer table WTB in the XY plane based on the measured values of linear encoders 70A to 70D, and controls the rotation of CD lever 46 in the θ z direction based on the measured values of encoders 70E and 70F. The structure of the linear encoder and the like will be described later.

The exposure apparatus 100 of the present embodiment is provided with a position measuring device for measuring positional information of the wafer W in the Z-axis direction. As shown in fig. 3, the exposure apparatus 100 according to the present embodiment is provided with a multipoint focal point position detection system of an oblique incidence system (hereinafter, simply referred to as "multipoint AF system") similar to that disclosed in, for example, japanese patent application laid-open No. 6-283403 (corresponding to U.S. Pat. No. 5,448,332), which is configured by an irradiation system 90a and a light receiving system 90b (see fig. 8). In the present embodiment, as an example, the irradiation system 90a is disposed on the-Y side of the-X end of the head unit 62C, and the light receiving system 90b is disposed on the-Y side of the + X end of the head unit 62A in a state opposed thereto.

Although not shown, the plurality of detection points of the multi-point AF system (90a,90b) are arranged at predetermined intervals in the X-axis direction on the detection surface. In the present embodiment, for example, the detection points are arranged in a matrix of M rows and M columns (M is the total number of detection points) or two rows and N columns (N is 1/2 of the total number of detection points). Fig. 3 does not individually show a plurality of detection points to which the detection beams are irradiated, but shows an elongated detection area (beam area) AF extending in the X-axis direction between the irradiation system 90a and the light receiving system 90 b. Since the length of the detection area AF in the X axis direction is set to be the same as the diameter of the wafer W, the substantially entire Z axis direction position information (surface position information) of the wafer W can be measured by scanning the wafer W only once in the Y axis direction. The detection area AF is disposed in the Y-axis direction between the liquid immersion area 14 (exposure area IA) and alignment systems (AL1, AL 2)₁,AL2₂,AL2₃,AL2₄) The detection operation can be performed by the multi-spot AF system and the alignment system at the same time. The multipoint AF system may be provided on a main frame or the like for holding the projection unit PU, but in the present embodiment, it is provided on the above-mentioned main frameAnd (4) measuring the frame.

The plurality of detecting points are arranged in 1 row, M column, or 2 rows, N column, but the number of rows and/or columns is not limited thereto. However, when the number of rows is 2 or more, it is preferable that the positions of the detection points in the X-axis direction are different between the rows. Further, the plurality of detection points are arranged along the X-axis direction, but the present invention is not limited to this, and for example, the plurality of detection points may be arranged along a direction intersecting both the X-axis and the Y-axis. That is, the plurality of detection points may be different in position at least in the X-axis direction. In the present embodiment, the detection beams are irradiated to the plurality of detection points, but the detection beams may be irradiated to the entire detection area AF, for example. The length of the detection area AF in the X-axis direction may not be the same as the diameter of the wafer W.

In the present embodiment, a pair of Z position measuring surface position sensors (hereinafter, simply referred to as "Z sensors") are provided in the vicinity of detection points located at both ends of a plurality of detection points of the multipoint AF system, that is, in the vicinity of both ends of the detection area AF, so as to be symmetrical with respect to the straight line LV. 72a,72b and 72c,72 d. These Z sensors 72a to 72d are fixed to the lower surface of a main frame, not shown. As the Z sensors 72a to 72d, for example, optical displacement sensors (optical pickup type sensors) configured as optical pickups used in CD drives and the like are used, and the optical displacement sensors irradiate light onto the wafer table WTB, receive the reflected light thereof, and measure positional information of the surface of the wafer table WTB in the Z-axis direction orthogonal to the XY plane at the irradiation point of the light. The Z sensors 72a to 72d may be provided on the measurement frame.

Further, head unit 62C includes a plurality of (six in each case, twelve in total) Z sensors 74 located on one side and the other side with respect to a straight line LH connecting a plurality of Y heads 64 in the X axis direction therebetween and arranged at predetermined intervals along two straight lines parallel to straight line LH_i，j(i-1, 2, j-1, 2, …, 6). At this time, the paired Z sensors 74_1，jZ sensor 74_2，jAnd is arranged symmetrically with respect to the straight line LH. Further, a plurality of pairs (here, six pairs) of Z sensors 74_1，jZ sensor 74_2，jAnd a plurality of Y heads 64 arranged alternately in the X axis direction. Each Z sensor 74_i，jFor example, the same optical pickup type sensors as the Z sensors 72a to 72d are used.

Here, each pair of Z sensors 74 located at positions symmetrical with respect to the straight line LH_1，j,74_2，jThe interval of (b) is set to be the same as the interval of the Z sensors 74c,74 d. In addition, a pair of Z sensors 74_1，4，74_2，4And is located on the same straight line parallel to the Y-axis direction as the Z sensors 72a,72 b.

The head unit 62A includes the plurality of Z sensors 74 with respect to the straight line LV_i，jA plurality of, here 12, Z sensors 76 arranged symmetrically_p，q(p ═ 1,2, q ═ 1,2, …, 6). Each Z sensor 76_p，qFor example, a CD pickup type sensor similar to the Z sensors 72a to 72d is used. In addition, a pair of Z sensors 76_1，3,76_2，3And is located on the same line in the Y axis direction as the Z sensors 72c,72 d. In addition, a Z sensor 76_i，j，76_p，qFor example, the measuring frame or the main frame. In the present embodiment, the Z sensors 72a to 72d and 74 are provided_i，j，74_p，qThe measurement system of (3) measures positional information of wafer stage WST in the Z-axis direction by one or more Z sensors facing the scale. Therefore, in the exposure operation, Z sensor 74 for position measurement is switched in accordance with the movement of wafer stage WST_i，j，76_p，q. Further, during the exposure operation, the Y scale 39Y₁With at least one Z sensor 76_p，qOpposed, and Y-scale 39Y₂With at least one Z sensor 74_i，jAre opposite. Therefore, the measurement system can measure not only the positional information of wafer stage WST in the Z-axis direction but also the positional information (roll) in the θ y direction. In the present embodiment, each Z sensor of the measurement system measures the grating surface (the surface on which the diffraction grating is formed) of the scale, but a surface different from the grating surface, for example, a surface of a cover glass covering the grating surface may be measured.

Note that, in fig. 3, measurement stage MST is not shown, and a liquid immersion area formed by water Lq held between measurement stage MST and tip lens 191 is denoted by reference numeral 14. In addition, in fig. 3, reference numeral 78 denotes a local air conditioning system for sending the dry air whose temperature is adjusted to a predetermined temperature to the vicinity of the light beam path of the multipoint AF system (90a,90b) via down-flow along the white arrows shown in fig. 3. Note that reference numeral UP denotes an unloading position at which the wafer is unloaded onto wafer table WTB, and reference numeral LP denotes a loading position at which the wafer is loaded onto wafer table WTB. In the present embodiment, the unloading position UP and the loading position LP are set symmetrically with respect to the straight line LV. The unloading position UP and the loading position LP can be set to the same position.

Fig. 6 shows a main configuration of a control system of the exposure apparatus 100. This control system is mainly composed of a main control unit 20 constituted by a microcomputer (or a workstation) for integrating the entire apparatus. The memory 34 of the external memory device connected to the main control device 20 stores correction information to be described later. In fig. 6, various sensors provided on measurement stage MST, such as uneven illuminance sensor 94, aerial image measuring device 96, and wavefront aberration sensor 98, are collectively referred to as a sensor group 99.

In exposure apparatus 100 of the present embodiment configured as described above, since the arrangement of the X scale and the Y scale on wafer table WTB and the arrangement of the X heads and the Y heads described above are employed, at least one X head 66 of the total 18X heads belonging to head units 62B,62D always faces X scale 39X in the effective stroke range of wafer stage WST (that is, the range moved for alignment and exposure operation in the present embodiment) as shown in the examples of fig. 7a and 7B₁,39X₂And at least one Y head 64 among at least 1Y heads belonging to the head units 62A,62C, respectively, or the Y head 64Y₁,64y₂Must face the Y scale 39Y₁,39Y₂. That is, at least one of the corresponding heads will be opposite at least three of the four scales.

In fig. 7(a) and 7(B), heads facing the corresponding X scale or Y scale are indicated by circled frames.

Therefore, main controller 20 can control the positional information (including the rotation information in the θ z direction) of wafer stage WST in the XY plane with high accuracy by controlling each motor constituting stage drive system 124 based on the measurement values of at least three encoders in total of at least one of encoders 70A,70C and encoders 70B and 70D in the effective stroke range of wafer stage WST. Since the influence of the air fluctuation on the measurement values of the encoders 70A to 70D is small enough to be almost negligible compared to the interferometer, the short-term stability of the measurement values due to the air fluctuation is much better than that of the interferometer.

When wafer stage WST is driven in the X-axis direction as indicated by the white arrow in fig. 7(a), Y head 64 for measuring the position of wafer stage WST in the Y-axis direction is indicated by arrow e in the figure₁,e₂Shown sequentially switched to the adjacent Y read head 64. For example, switching from the Y head 64 framed by the solid circles to the Y head 64 framed by the broken circles. Thus, the measurement values are continued before and after this switching. That is, in the present embodiment, in order to smoothly switch the Y heads 64 and connect the measurement values, the interval between adjacent Y heads 64 provided in the head units 62A and 62C is set to be larger than the Y scale 39Y₁,39Y₂The width in the X-axis direction is narrow.

In the present embodiment, the distance between adjacent Y heads 66 of the head units 62B and 62D is set to be larger than the distance between the X scales 39X and 39X as described above₁,39X₂Since the width in the Y-axis direction is narrow, when wafer stage WST is driven in the Y-axis direction as indicated by the white arrow in fig. 7(B), X heads 66 for measuring the position of wafer stage WST in the X-axis direction are sequentially switched to adjacent X heads 66 (for example, X heads 66 framed by a solid circle are switched to X heads 66 framed by a dashed circle), and the measurement values are continued before and after this switching.

Next, the configuration of the encoders 70A to 70F will be described with the Y encoder 70A shown in fig. 8(a) in an enlarged scale as a representative. Fig. 8a shows a method for irradiating detection light (measuring beam) on the Y scale 39Y₁One Y head 64 of the head unit 62A.

The Y head 64 is roughly divided into three parts, i.e., an irradiation system 64a, an optical system 64b, and a light receiving system 64 c.

The irradiation system 64a includes a light source (e.g., a semiconductor laser LD) that emits a laser beam LB in a direction at 45 ° with respect to the Y axis and the Z axis, and a converging lens L1 disposed on the optical path of the laser beam LB emitted from the semiconductor laser LD.

The optical system 64b includes a polarizing beam splitter PBS whose separation plane is parallel to the XZ plane, a pair of mirrors R1a, R1b, lenses L2a, L2b, quarter wavelength plates (hereinafter referred to as λ/4 plates) WP1a, WP1b, mirrors R2a, R2b, and the like.

The light receiving system 64c includes a polarizer (light detector), a photodetector, and the like.

In the Y encoder 70A, the laser beam LB emitted from the semiconductor laser LD is incident on the polarization beam splitter PBS via the lens L1, and the polarized beam is split into two beams LB₁,LB₂. Light beam LB transmitted through polarizing beam splitter PBS₁Reaches the Y scale 39Y via the mirror R1a₁The reflection type diffraction grating RG of (1), the light beam LB reflected by the polarization beam splitter PBS₂It reaches the reflection type diffraction grating RG via the mirror R1 b. Here, "polarization separation" means separation of an incident light beam into a P-polarized component and an S-polarized component.

Through the light beam LB₁,LB₂A predetermined number of diffracted beams, for example, first diffracted beams, generated from the diffraction grating RG by irradiation of (1) are converted into circularly polarized light by the λ/4 plates WP1a and WP1b via the lenses L2b and L2a, reflected by the mirrors R2a and R2b, passed through the λ/4 plates WP1a and WP1b again, and reached the polarization beam splitter PBS in the opposite direction of the same optical path as the return path。

The two light beams that reach the polarization beam splitter PBS have their polarization directions rotated by 90 degrees with respect to the original direction. Thus, the light beam LB that is transmitted through the polarizing beam splitter PBS first₁The first diffracted beam (LB) is reflected by the Polarizing Beam Splitter (PBS), enters the light receiving system (64 c), and is reflected by the Polarizing Beam Splitter (PBS)₂The primary diffracted beam of (1) is transmitted through the polarizing beam splitter PBS and then is combined with the beam LB₁The resultant is coaxially incident on the light receiving system 64 c.

Next, the two primary diffracted light beams are aligned in the polarization direction by the light-receiving element in the light-receiving system 64c, and interfere with each other to be interference light, which is detected by the light detector and converted into an electric signal corresponding to the intensity of the interference light.

As is clear from the above description, in the Y encoder 70A, since the optical path lengths of the two light fluxes interfering with each other are extremely short and substantially equal, the influence of air fluctuation can be almost ignored. In addition, when the Y scale 39Y₁That is, when wafer stage WST moves in the measurement direction (in this case, the Y-axis direction), the respective phases of the two light beams change, and the intensity of the interference light changes. The intensity change of the interference light is detected by the light receiving system 64c, and the positional information corresponding to the intensity change is output as the measurement value of the Y encoder 70A. The other encoders 70B,70C,70D, etc. are also configured in the same manner as the encoder 70A.

On the other hand, when wafer stage WST moves in a direction different from the Y-axis direction, head 64 and Y scale 39Y move₁In the case where the relative movement is performed in a direction other than the direction to be measured (relative movement in a non-measurement direction), a measurement error occurs in the Y encoder 70A in most cases. Hereinafter, the case where this measurement error occurs will be described.

First, two return beams LB are derived₁,LB₂Intensity of the combined interference light, and Y scale 39Y₂The relationship of the shift (relative shift to Y head 64) of (reflection type diffraction grating RG).

In FIG. 8(B), the return beam LB reflected by the mirror R1a₁At an angle theta_a0Incident on a reflection type diffraction grating RG to be reflected at theta_a1Generating n_aThe diffracted light of the order of magnitude. The return beam reflected by the mirror R2a and following the return path is at an angle θ_a1Enters the reflection type diffraction grating RG. The diffracted light is then generated again. Here, in θ_a0The diffracted light generated to travel along the original optical path to the mirror R1a is n times the diffracted light generated in the return path_aThe diffracted light of the order of magnitude.

On the other hand, the return beam LB reflected by the mirror R1b₂At an angle θ_b0Incident on a reflection type diffraction grating RG to be reflected at theta_b1Generating n_bThe diffracted light of the order of magnitude. This diffracted light is reflected by the mirror R2b and returns to the mirror R1b along the same optical path.

In this case, two return beams LB₁,LB₂The intensity I of the combined interference light and two return beams LB at the light receiving position of the photodetector₁,LB₂The phase difference (phase difference) phi therebetween depends on the relationship I ∈ 1+ cos phi. However, the intensities LB of the two beams₁,LB₂Are equal to each other.

Here, although a detailed method for deriving the phase difference Φ is omitted, it can be theoretically obtained by the following equation (7).

φ＝KΔL+4π(n_b－n_a)ΔY/p

+2KΔZ(cosθ_b1+cosθ_b0－cosθ_a1－cosθ_a0)…(7)

Here, K Δ L is due to two beams LB₁,LB₂Δ Y is a shift in the + Y direction of the reflection type diffraction grating RG, Δ Z is a shift in the + Z direction of the reflection type diffraction grating RG, p is a pitch of the diffraction grating, n_b－n_aIs the diffraction order of each diffracted light.

Here, the encoder is configured to satisfy symmetry as shown in the following equation (8) with the optical path difference Δ L being 0.

θ_a0＝cosθ_b0、θ_a1＝cosθ_b1…(8)

At this time, since the third term on the right side of the expression (7) is zero in parentheses, n is satisfied at the same time_b＝－n_a(═ n), so that sub-formula (9) can be obtained.

φ_sym(ΔY)＝2πΔY/(p/4n)…(9)

From the above (9), the phase difference φ_symNot depending on the wavelength of the light.

Here, two cases of fig. 9(a) and 9(B) are briefly described for analysis. First, in the case of fig. 9(a), the optical axis of head 64 coincides with the Z-axis direction (head 64 is not tilted). Here, wafer stage WST has been shifted in the Z-axis direction (Δ Z ≠ 0, Δ Y ═ 0). At this time, since the optical path difference Δ L does not change, the term 1 on the right side of the expression (7) does not change. The 2 nd term is zero assuming that Δ Y is 0. Next, the 3 rd term is zero because it satisfies the symmetry of the equation (8). In summary, the phase difference Φ does not change, and the intensity of the interference light does not change. As a result, the measured value (count value) of the encoder does not change.

On the other hand, in the case of fig. 9B, the optical axis of head 64 is inclined with respect to the Z axis (head 64 is inclined). In this state, wafer stage WST has been shifted in the Z-axis direction (Δ Z ≠ 0, Δ Y ═ 0). In this case, similarly, since the optical path difference Δ L does not change, the term 1 on the right side of the expression (7) does not change. The 2 nd term is zero assuming that Δ Y is 0. However, since the symmetry of equation (8) is broken by the head tilt, the 3 rd term is not zero but varies in proportion to the Z shift Δ Z. In summary, the phase difference φ changes, which results in a change in the measured value. Even if the head 64 does not fall, the symmetry of the equation (8) is broken by, for example, the optical characteristics of the head (telecentricity) and the like, and the measurement value is similarly changed. That is, the measurement error of the encoder system generates characteristic information of the head unit, which is a main factor, and includes not only the inclination of the head but also the optical characteristics thereof.

In addition, although not shown, when wafer stage WST is displaced in a direction perpendicular to the measurement direction (Y-axis direction) and the optical axis direction (Z-axis direction) (Δ X ≠ 0, Δ Y ═ 0, and Δ Z ═ 0), the direction (longitudinal direction) in which the grid lines of diffraction grating RG face does not change in measurement value only when the direction is orthogonal to the measurement direction, but sensitivity is generated with a gain proportional to the angle thereof if the direction is not orthogonal.

Next, four cases shown in fig. 10(a) to 10(D) are analyzed. First, in the case of fig. 10 a, the optical axis of head 64 coincides with the Z-axis direction (head 64 is not tilted). In this state, even if wafer stage WST moves in the + Z direction to reach the state of fig. 10(B), the measurement value of the encoder does not change, as in the case of fig. 9(a) described above.

Next, assume that in the state of fig. 10(B), wafer stage WST rotates around the X axis to become the state shown in fig. 10 (C). At this time, although the head and the scale do not move relatively, that is, Δ X ═ Δ Z ═ 0, the optical path difference Δ L changes due to the rotation of wafer stage WST, and therefore the measurement value of the encoder changes. That is, a measurement error occurs in the encoder system due to the tilt (tilt) of wafer stage WST.

Next, assume that in the state of fig. 10(C), wafer stage WST moves downward to be in the state shown in fig. 10 (D). At this time, since wafer stage WST does not rotate, optical path difference Δ L does not change. However, since the symmetry of equation (8) is broken, it is known from the right-hand term 3 of equation (7) that the phase difference Φ changes due to the Z shift Δ Z. In this way, the encoder measurements will vary. In the case of fig. 10(D), the measured values of the encoder are the same as those of fig. 10 (a).

As is understood from the results of the simulation by the inventors, the measurement value of the encoder has sensitivity not only to the change in the scale position in the Y-axis direction in the measurement direction but also to the change in the attitude in the θ x direction (pitch) and the θ Z rotation (yaw), and depends on the change in the position in the Z-axis direction even when the above-described symmetry is broken. That is, the theoretical explanation above is consistent with the simulation results.

Therefore, in the present embodiment, correction information for correcting a measurement error of each encoder due to relative movement of the head and the scale in the non-measurement direction is acquired as follows.

a. First, main controller 20 drives wafer stage WST via stage drive system 124 while monitoring the measurement values of Y interferometer 16, X interferometer 126, and Z interferometers 43A,43B of interferometer system 118, and causes Y head 64 closest to the-Y side of head unit 62A to oppose Y scale 39Y on the upper surface of wafer table WTB as shown in fig. 11(a) and 11(B)₁An arbitrary region (a region enclosed by a circle in fig. 11 a) AR.

b. Then, main controller 20 drives wafer table WTB (wafer stage WST) based on the measurement values of Y interferometer 16 and Z interferometers 43A and 43B such that roll amount θ Y and yaw amount θ Z of wafer table WTB (wafer stage WST) are both zero and pitch amount θ x becomes a desired value a₀(here, a0 is 200 μ rad), and after driving, the Y head 64 irradiates the Y scale 39Y with detection light₁And stores the measurement value corresponding to the photoelectric conversion signal from the head 64 that receives the reflected light thereof in the internal memory.

c. Next, main controller 20 maintains the posture of wafer table WTB (wafer stage WST) (pitch θ Y is a) based on the measurement values of Y interferometer 16 and Z interferometers 43A and 43B₀Yaw amount θ Z is 0 and roll amount θ Y is 0), and wafer table WTB (wafer stage WST) is driven in the Z-axis direction within a predetermined range, for example, within a range of-100 μm to +100 μm, as indicated by an arrow in fig. 11B, and during this driving, head 64 is directed to Y scale 39Y₁The area AR of (a) irradiates the detection light, and sequentially captures measurement values corresponding to the photoelectric conversion signal from the reading head 64 receiving the reflected light thereof at prescribed sampling intervals, and stores them in the internal memory.

d. Next, the main control deviceBased on the measurement value of Y interferometer 16, pitch amount of wafer stage WTB (wafer stage WST) is changed to (θ x α)₀－△α)。

e. Next, the same operation as in the above-described c. is repeated with respect to the posture after the change.

f. Thereafter, the operations of d and e are alternately repeated, and the measurement value of the head 64 in the Z driving range is acquired at an interval of Δ α (rad), for example, 40 μ rad, in a range of the pitch amount θ x, for example, -200 μ rad < θ x < +200 μ rad.

g. Next, by marking each data in the internal memory obtained through the processes from b to e on a two-dimensional coordinate system having the horizontal axis as the Z position and the vertical axis as the encoder measurement value, sequentially connecting the marking points when the pitch amounts are the same, and displacing the horizontal axis in the vertical axis direction so that the line where the pitch amount is zero (the horizontal line in the center) passes through the origin, a graph (a graph showing the measurement value change characteristics of the encoder (head) corresponding to the Z leveling of the wafer stage) as shown in fig. 12 can be obtained.

The value of the vertical axis of each point on the graph of fig. 12 is necessarily the measurement error of the encoder at each Z position for which the pitch θ x is α. Therefore, main control device 20 creates a data table of the pitch amounts θ x and Z positions of each point on the graph of fig. 12 and the encoder measurement error, and stores the data table as stage position induced error correction information in memory 34 (see fig. 6). Alternatively, main controller 20 calculates an indeterminate coefficient by, for example, a least square method using a function of Z position Z and pitch amount θ x as a measurement error, and stores the function in memory 34 as stage position induced error correction information.

h. Next, main controller 20 drives wafer stage WST by a predetermined amount in the-X direction via stage drive system 124 while monitoring the measurement values of X interferometer 126 of interferometer system 118, and causes the second Y head 64 (head near Y head 64 from which data has been acquired) from the-X side end of head unit 62A to oppose Y scale 39Y on the upper surface of wafer table WTB as shown in fig. 13₁The aforementioned area AR (the area indicated by a circle in fig. 13).

i. Subsequently, even if the Y head 64 performs the same processing as described above, the main controller 20 causes the Y head 64 and the Y scale 39Y to move together₁The correction information of the constituted Y encoder 70A is stored in the memory 34.

j. Thereafter, similarly, the remaining Y heads 64 and the Y scale 39Y of the head unit 62A are obtained₁Correction information of the constituted Y encoder 70A, each X head 66 of the head unit 62B, and the X scale 39X₁Correction information of the X encoder 70B, each X head 64 of the head unit 62C, and the Y scale 39Y₂Correction information of the constituted Y encoder 70C, each X head 66 of the head unit 62D, and the X scale 39X₂The correction information of the X encoder 70D is stored in the memory 34.

It is important here that when the measurement is performed using each X head 66 of the head unit 62B, the X scale 39X is used as described above₁In the same region as above, when the above measurement is performed using each Y head 64 of the head unit 62C, the Y scale 39Y is used₂In the same region as above, when the above measurement is performed using each Y head 66 of the head unit 62D, the X scale 39X is used₂The same region of (a). The reason for this is that, as long as the correction of each interferometer of interferometer system 118 (including the curvature correction of reflection surfaces 17a,17b and reflection surfaces 41a,41b,41 c) is completed, the posture of wafer stage WST can be set to a desired posture at any time based on the measurement values of these interferometers, and by using the same portion of each scale, measurement errors occur between the heads without being affected by the inclination of the scale surface.

In addition, main controller 20 targets Y head 64Y₁,64y₂As with the Y heads 64 of the head units 62C and 64A, the Y scales 39Y and 64Y are used, respectively₂,39Y₂The same region as the Y scale 39Y is obtained by performing the above measurement₂Opposing Y head 64Y₁Correction information of (encoder 70C) and Y scale 39Y₁Opposing Y head 64Y₂The correction information (of the encoder 70A) is stored in the memory 34.

Next, main controller 20 sequentially changes the yaw amount θ Z of wafer stage WST in the range of-200 μ rad < θ Z < +200 μ rad while maintaining the pitch amount and the roll amount of wafer stage WST at zero in the same order as in the case of changing the pitch amount described above, and at each position, drives wafer table WTB (wafer stage WST) in the Z-axis direction in a predetermined range, for example, in the range of-100 μm to +100 μm, and sequentially captures the measurement values of heads 64 at predetermined sampling intervals during this driving and stores the measurement values in an internal memory. The measurement is performed by all the heads 64 and 66, and the data in the internal memory is marked on a two-dimensional coordinate system having the horizontal axis as the Z position and the vertical axis as the encoder measurement value in the same order as described above, the marked points having the same yaw amount are connected in order, and the horizontal axis is displaced so as to pass through the origin by a line (central transverse line) having the yaw amount zero, thereby obtaining the same graph as that of fig. 12. Next, the main controller 20 creates a data table of the yaw amounts θ Z, Z positions and measurement errors of each point on the obtained graph, and stores the data table as correction information in the memory 34. Alternatively, the main controller 20 calculates an indeterminate coefficient by using the measurement error as a function of the Z position Z and the yaw amount θ Z, for example, by a least squares method, obtains the function, and stores the function in the memory 34 as correction information.

Here, when the amount of pitch of wafer stage WST is not zero and the amount of yaw is not zero, the measurement error of each encoder at Z position of wafer stage WST may be considered as a simple sum (linear sum) of the measurement error corresponding to the amount of pitch and the measurement error corresponding to the amount of yaw at Z position Z. The reason for this is that, as a result of simulation, even when the amount of yaw is changed, the measurement error (count value (measurement value)) linearly changes with the change in the Z position.

For simplicity of explanation, functions of the pitch amount θ x, the yaw amount θ Z, and the Z position Z of wafer stage WST, which are expressed by the following equation (10), are obtained for the Y head of each Y encoder, and stored in memory 34. For the X head of each X encoder, a function of the roll amount θ y, the yaw amount θ Z, and the Z position Z of wafer stage WST, which is expressed by the following equation (11) and indicates measurement error Δ X, is obtained and stored in memory 34.

△y＝f(z,θx,θz)＝θx(z－a)+θz(z－b)…(10)

△x＝g(z,θy,θz)＝θy(z－c)+θz(z－d)…(11)

In the above equation (10), a is the Z coordinate of the point where the respective straight lines of the graph of fig. 12 intersect, and b is the Z coordinate of the point where the respective straight lines of the same graph as fig. 12 intersect when the yaw amount is changed in order to obtain the correction information of the Y encoder. In the above equation (11), c is the Z coordinate of the point where the straight lines of the same graph as in fig. 12 intersect when the roll amount is changed to acquire the correction information of the X encoder, and d is the Z coordinate of the point where the straight lines of the same graph as in fig. 12 intersect when the yaw amount is changed to acquire the correction information of the X encoder.

Next, a parallel processing operation using wafer stage WST and measurement stage MST in exposure apparatus 100 according to the present embodiment will be described with reference to fig. 14 to 27. In the following operation, the opening and closing of the valves of the liquid supply device 5 and the liquid recovery device 6 of the local immersion device 8 are controlled as described above via the main control device 20, and water is filled in the front end lens 191 of the projection optical system PL as needed. In the following description, for the sake of easy understanding, the description about the control of the liquid supply device 5 and the liquid recovery device 6 is omitted. In the following description of the operation, although a plurality of drawings are used, the same reference numerals may be assigned to the same members in each drawing, and the same reference numerals may not be assigned in some cases. That is, the same configuration is used for each drawing regardless of whether a symbol is present or absent in the drawings, although the symbols in the drawings are different. This point is the same as that of each drawing used in the description so far.

Fig. 14 shows a state in which step-and-scan exposure is performed on wafer W on wafer stage WST (here, a wafer W in the middle of a certain lot (one lot is 25 or 50 wafers)). At this time, measurement stage MST may be kept waiting at a retracted position where collision with wafer stage WST is avoided, but in the present embodiment, moves following wafer stage WST by keeping a predetermined distance. Therefore, it is sufficient that the distance of movement of measurement stage MST after the end of exposure when moving to the contact state (or close state) with wafer stage WST is the same as the predetermined distance.

In this exposure, the main controller 20 is controlled to respectively face the X scales 39X₁,39X₂Two X heads 66(X encoders 70B,70D) shown in a circle frame in FIG. 14, and two X heads facing the Y scale 39Y₁,39Y₂Among two Y heads 64(Y encoders 70A,70C) shown by a circle in fig. 18, the measurement values of at least three encoders, stage position induced error correction information (correction information obtained by the above-described equation (10) or equation (11)) of each encoder corresponding to the pitch amount, the roll amount, the yaw amount, and the Z position of wafer stage WST measured by interferometer system 118, and correction information of the grid pitch of each scale and warp correction information of the grid line control wafer table WTB (wafer stage WST) in the XY plane (including θ Z rotation). Further, main controller 20 controls the positions of one side end and the other side end (Y scale 39Y in the present embodiment) of the surface of wafer table WTB in the X-axis direction₁,39Y₂) Each pair of Z sensors 74_1,j,74_2,j,76_1,q,76_2,qThe position of wafer table WTB in the Z-axis direction, and the θ y rotation (roll) and the θ x rotation (pitch) are controlled. In addition, the position of wafer table WTB in the Z-axis direction and the θ y rotation (roll) are based on Z sensor 74_1,j,74_2,j,76_1,q,76_2,qAnd thetax rotation (pitch) can also be controlled based on the measurements of the Y interferometer 16. In any case, during this exposure, control of the position of wafer table WTB in the Z-axis direction, the θ y rotation, and the θ x rotation (focus leveling control of wafer W) is performed based on the result of focus matching performed in advance by the multipoint AF system.

The exposure operation is performed in advance by the main controller 20Results of wafer alignment (e.g., EGA, enhanced full wafer alignment) and alignment systems AL1, AL2₁～AL2₂The latest baseline of (a) is obtained by repeating an inter-irradiation-area movement operation of moving wafer stage WST to a scanning start position (acceleration start position) for exposing each irradiation area on wafer W and a scanning exposure operation of transferring the pattern formed on reticle R to each irradiation area by a scanning exposure method. The exposure operation is performed with water held between the front end lens 191 and the wafer W. In addition, exposure is performed in the order of the irradiation region located on the-Y side to the irradiation region located on the + Y side of fig. 18. The EGA method is disclosed in, for example, U.S. Pat. No. 4,780,617.

Next, before the final shot area on wafer W is exposed, main controller 20 controls stage drive system 124 based on the measurement value of Y interferometer 18 while maintaining the measurement value of X interferometer 130 at a constant value, and moves measurement stage MST (measurement table MTB) to the position shown in fig. 15. At this time, the-Y side end surface of CD lever 46 (measurement table MTB) comes into contact with the + Y side end surface of wafer table WTB. Further, for example, the measurement values of an interferometer or an encoder for measuring the positions of the respective tables in the Y axis direction may be monitored, and the measurement table MTB and the wafer table WTB may be separated by about 300 μm in the Y axis direction to be kept in a non-contact state (close state). After the positional relationship shown in fig. 15 is set in the exposure of the wafer W, the wafer stage WST and the measurement stage MST are moved so as to maintain the positional relationship.

Next, as shown in fig. 16, main controller 20 starts the operation of driving measurement stage MST in the-Y direction and driving wafer stage WST to unload position UP while maintaining the positional relationship between wafer table WTB and measurement table MTB in the Y-axis direction. When this operation starts, measurement stage MST moves only in the-Y direction in the present embodiment, and wafer stage WST moves in the-Y direction and the-X direction.

When wafer stage WST and measurement stage MST are simultaneously driven by main controller 20 in this manner, water held between tip lens 191 of projection unit PU and wafer W (water in immersion area 14 shown in fig. 16) moves in the order of wafer W → plate body 28 → CD lever 46 → measurement table MTB as wafer stage WST and measurement stage MST move to the-Y side. In addition, during the movement, wafer table WTB and measurement table MTB maintain the contact state (or the proximity state). Fig. 16 shows a state immediately before the water in the liquid immersion area 14 moves from the plate 28 to the CD bar 46. In the state shown in fig. 16, the position (including θ Z rotation) of wafer table WTB (wafer stage WST) in the XY plane is controlled by main controller 20 based on the measurement values of three encoders 70A,70B,70D (and correction information of encoders 70A,70B, or 70D stored in memory 34 in correspondence with the pitch amount, roll amount, yaw amount, and Z position of wafer stage WST measured by interferometer system 118).

When wafer stage WST and measurement stage MST are simultaneously driven by a small distance in the-Y direction from the state of fig. 16, since Y encoder 70A (70C) cannot measure the position of wafer stage WST (wafer table WTB), at the point immediately before that time, main control device 20 switches control of the Y position and θ Z rotation of wafer stage WST (wafer table WTB) from control based on the measurement values of Y encoders 70A,70C to control based on the measurement values of Y interferometer 16 and Z interferometers 43A, 43B. Next, after a predetermined time, as shown in fig. 17, the measurement stage MST reaches a position where the baseline measurement (hereinafter also referred to as Sec-BCHK (time interval) as appropriate) of the secondary alignment system is performed at a predetermined time interval (here, the time interval for each wafer replacement). Next, main controller 20 stops measurement stage MST at this position, and passes through X scale 39X₁While X head 66(X linear encoder 70B) indicated by a circle in fig. 17 facing thereto measures the X position of wafer stage WST, Y interferometer 16 and Z interferometers 43A and 43B measure the Y axis direction, θ Z rotation, and the like, wafer stage WST is further driven to unload position UP and stopped at unload position UP. In the state of fig. 17, water is held between measuring table MTB and tip lens 191.

Next, as shown in FIGS. 17 and 18, the main control device 20 is based on the data shown in FIG. 18Y head 64Y shown in a circle and respectively facing a pair of reference grids 52 on a CD bar supported by a measurement stage MST₁,64y₂The measurement values of the aforementioned Y-axis linear encoders 70E,70F are configured to adjust the θ z rotation of the CD bar 46, and the XY position of the CD bar 46 is adjusted based on the measurement values of a primary alignment system AL1 (indicated by a circle in fig. 18) for detecting a reference mark M located on or near the center line CL of the measurement table MTB. Next, in this state, master control device 20 uses four No. 2 alignment systems AL2₁～AL2₄The reference marks M on the CD rod 46 in the field of view of each secondary alignment system are measured simultaneously to perform Sec-BCHK (time interval) to determine four 2 nd alignment systems AL2 respectively₁～AL2₄The baseline of (the relative position of the four 2 nd alignment systems with respect to the 1 st alignment system AL 1). In parallel with this Sec-BCHK (time interval), main controller 20 gives a command to a drive system of an unillustrated unloading arm to unload wafer W on wafer stage WST stopped at unloading position UP, raises vertical moving pins CT (not shown in fig. 17, see fig. 18) driven to be raised by a predetermined amount during unloading, and drives wafer stage WST in the + X direction to move it to loading position LP.

Next, main controller 20 moves measurement stage MST to an optimum standby position (hereinafter referred to as "optimum scram standby position") at which measurement stage MST is moved from a state of being separated from wafer stage WST to the aforementioned contact state (or proximity state) with wafer stage WST, as shown in fig. 19. The main controller 20 instructs a drive system of a loading arm, not shown, to load a new wafer W onto the wafer table WTB, in parallel with the above operation. At this time, since the vertical movement pins CT are maintained in a state of being raised by a predetermined amount, the wafer loading operation can be performed in a shorter time as compared with the case where the vertical movement pins CT are lowered and driven to be accommodated in the wafer holder. Fig. 19 shows a state in which the wafer W is mounted on the wafer table WTB.

In the present embodiment, the optimum emergency stop standby position of measurement stage MST is set as appropriate based on the Y coordinate of the alignment mark provided in the alignment irradiation region on the wafer. In the present embodiment, the optimum emergency stop standby position is set to a position at which wafer stage WST can be stopped at a position at which wafer alignment is performed and can be moved to a contact state (or a close state).

Next, as shown in fig. 20, main controller 20 moves wafer stage WST from loading position LP to a position where fiducial marks FM on measurement plate 30 are positioned within the field of view (detection area) of primary alignment system AL1 (i.e., a position where the first half of the baseline measurement (Pri-BCHK) of the primary alignment system is performed). During this movement, main controller 20 switches the control of the position of wafer table WTB in the XY plane from the control of the measurement value in the X axis direction by encoder 70B and the control of the measurement value in the Y axis direction and θ Z rotation) by Y interferometer 16 and Z interferometers 43A and 43B to the position control in the XY plane based on the following information, that is: opposite to the X scale 39X₁,39X₂At least one of the two X heads 66 (encoders 70B,70D), indicated by a circled frame in FIG. 20, faces the Y scale 39Y₁,39Y₂Two Y heads 64Y indicated by circled boxes in FIG. 24₂,64y₁The measurement values of at least three of the encoders (encoders 70A,70C), stage position induced error correction information (correction information obtained by the above-described equation (10) or equation (11)) of each encoder corresponding to the pitch amount, roll amount, yaw amount, and Z position of wafer stage WST measured by interferometer system 118, and correction information of the grid pitch of each scale and warp correction information of the grid line.

Subsequently, the main controller 20 performs the first half of the Pri-BCHK process of detecting the reference marks FM using the primary alignment system AL 1. At this time, measurement stage MST is waiting at the optimum scram position.

Next, main controller 20 starts moving wafer stage WST in the + Y direction toward the position for detecting the alignment marks provided in the three first alignment irradiation areas while managing the position of wafer stage WST based on the measurement values of the at least three encoders and the correction information. Next, when wafer stage WST reaches the position shown in fig. 21, main control device 20 stops wafer stage WST. Before that, main controller 20 activates (turns on) Z sensors 72a to 72d at or before the time when Z sensors 72a to 72d are placed on wafer table WTB to start measurement of the Z position and tilt (θ y rotation and θ x rotation) of wafer table WTB.

After wafer stage WST stops, main control apparatus 20 uses primary alignment system AL1 and secondary alignment system AL2₂,AL2₃The alignment marks (see the star marks in fig. 21) attached to the three first alignment shot areas AS are detected substantially simultaneously and independently, and the three alignment systems AL1 are used₁,AL2₂,AL2₃And the measured values of the at least three encoders (the measured values of the correction information after correction) at the time of the detection are stored in the internal memory so as to be associated with each other.

As described above, in the present embodiment, when the position of the alignment mark in the first alignment irradiation region is detected, the movement to the state where measurement stage MST and wafer stage WST are brought into contact (or close state) is terminated, and the movement of both stages WST in the contact state (or close state) is started by main controller 20, and MST moves from the position in the + Y direction (step movement to the position for detecting the alignment mark attached to the five second alignment irradiation regions). Before the movement of both stages WST and MST in the + Y direction is started, main controller 20 starts irradiation of wafer table WTB with the detection beam from irradiation system 09a of multipoint AF system (90a and 90b) as shown in fig. 21. Thereby forming a detection area of the multipoint AF system on wafer table WTB.

Next, when both stages WST, MST reach the positions shown in fig. 22 during the movement of both stages WST, MST in the + Y direction, main control device 20 performs the first half of the above-described focus correction, and obtains the relationship between the measurement values of Z sensors 72a,72b,72c,72d (surface position information of one side of wafer table WTB in the X-axis direction and the other side end) and the detection result (surface position information) of the multipoint AF system (90a,90b) with respect to the detection point on the surface of measurement plate 30 (the detection point located at or near the center among the plurality of detection points) in a state where the straight line (center line) in the Y-axis direction passing through the center of wafer table WTB (approximately aligned with the center of wafer W) coincides with straight line LV. At this time, liquid immersion area 14 is formed near the boundary between CD bar 46 and wafer table WTB. That is, the liquid immersion area 14 is moved from the CD bar 46 to the wafer table WTB.

Then, when the two stages WST and MST are further moved in the + Y direction while maintaining the contact state (or the close state) and reach the positions shown in fig. 23, the five alignment systems AL1 and AL2 are used₁～AL2₄The alignment marks (see the star marks in fig. 23) attached to the five second alignment irradiation regions are detected substantially simultaneously and independently, and the five alignment systems AL1 and AL2 are used₁～AL2₄And the measured values of the three encoders 70A,70C,70D (corrected measured values of the correction information) at the time of the detection are stored in the internal memory in such a manner as to be associated with each other. At this time, since there is no X scale 39X₁Since the X head is positioned on the Y-axis direction line LV which passes through the optical axis of the projection optical system PL, the main control device 20 is based on the X scale 39X₂The position of wafer table WTB in the XY plane is controlled by the measurement values of opposing X head 66(Y linear encoder 70D) and Y linear encoders 70A, 70C.

As described above, in the present embodiment, position information (two-dimensional position information) of eight alignment marks in total can be detected at the time when the detection of the alignment mark in the second alignment irradiation region is completed. At this stage, the main controller 20 may perform statistical calculations disclosed in, for example, japanese patent application laid-open No. 61-44429 (corresponding to U.S. patent No. 4,780,617) using the position information to determine a scale (illumination magnification) of the wafer W, and control the adjusting device 68 (see fig. 6) based on the calculated illumination magnification to adjust the optical characteristics of the projection optical system PL, for example, the projection magnification. The adjusting device 68 can adjust the optical characteristics of the projection optical system PL by, for example, driving a specific movable lens constituting the projection optical system PL or changing the gas pressure inside a gas-tight chamber formed between specific lenses constituting the projection optical system PL.

After the simultaneous detection operation of the alignment marks provided in the five second alignment irradiation areas is completed, main controller 20 resumes the movement of both stages WST and MST in the contact state (or the proximity state) in the + Y direction, and starts the above-described focus matching using Z sensors 72a to 72d and the multi-point AF systems (90a and 90b), as shown in fig. 23.

Next, when the two stages WST and MST reach the position where the measurement plate 30 is disposed directly below the projection optical system PL shown in fig. 24, the main controller 20 performs the second half of the Pri-BCHK processing and the second half of the focus correction processing described above. The second half of the Pri-BCHK processing herein is processing for measuring a pair of measurement mark projection images (aerial images) on the reticle R projected by the projection optical system PL using the aerial image measuring apparatus 45 (the aerial image measurement slit pattern SL is formed on the measurement plate 30), and storing the measurement results (aerial image intensities corresponding to the XY positions of the wafer table WTB) in the internal memory. In this process, for example, the aerial image of the pair of measurement marks can be measured by the slit scanning type aerial image measuring operation using the pair of aerial image measuring slit patterns SL in the same manner as the method disclosed in the above-mentioned U.S. patent application publication No. 2002/0041377 or the like. The second half of the focus correction is a process in which main controller 20 measures an aerial image of a measurement mark formed on reticle R or reticle stage RST, not shown, by using aerial image measuring device 45 while controlling the position (Z position) of measurement plate 30 (wafer table WTB) in the optical axis direction of projection optical system PL based on surface position information measured by Z sensors 72a,72b,72c, and 72d as shown in fig. 24, and measures the optimum focus position of projection optical system PL based on the result of the measurement. The measurement operation of the projected image of the measurement mark is disclosed in, for example, pamphlet of international publication No. 2005/124834. The main controller 20 acquires the Z sensor 74 in synchronization with the acquisition operation of the output signal from the aerial image measuring device 45 while moving the measurement stage 30 in the Z-axis direction_1,4、74_2,4Z sensingDevice 76_1,3、76_2,3Is measured. Next, the Z sensor 74 corresponding to the best focus position of the projection optical system PL is detected_1,4、74_2,4Z sensor 76_1,3、76_2,3The value of (c) is stored in a memory not shown. In the second half of the focus correction, the position (Z position) of the measurement plate 30 (wafer stage WST) in the optical axis direction of the projection optical system PL is controlled using the surface position information measured by the Z sensors 72a,72b,72c, and 72d because the second half of the focus correction is performed during the focusing.

At this time, since the liquid immersion area 14 is formed between the projection optical system PL and the measurement plate 30 (wafer table WTB), the aerial image is measured via the projection optical system PL and the water Lq. Further, since measurement plate 30 and the like are mounted on wafer stage WST (wafer table WTB) and light-receiving elements and the like are mounted on measurement stage MST, the aerial image is measured while wafer stage WST and measurement stage MST are kept in contact with each other (or in close proximity to each other), as shown in fig. 24. From the above measurement, the Z sensor 74 is found in a state where the line in the Y-axis direction passing through the center of the wafer table WTB, which corresponds to the best focus position of the projection optical system PL, coincides with the line LV_1,4、74_2,4、76_1,3、76_2,3I.e., the face position information of wafer table WTB.

Next, the main controller 20 calculates a baseline of the primary alignment system AL1 from the result of the first half of the Pri-BCHK process and the result of the second half of the Pri-BCHK process. Meanwhile, main control device 20 calculates the relationship between the measurement values of Z sensors 72a,72b,72c,72d (surface position information of wafer table WTB) obtained in the first half of the focus correction process and the detection results (surface position information) at the detection points of the surface of measurement plate 30 by the multipoint AF system (90a,90b), and calculates the best focus position of projection optical system PL obtained in the second half of the focus correction process based on Z sensor 74_1,4、74_2,4、76_1,3、76_2,3Determines the best focus of the multi-spot AF system (90a,90b) on the projection optical system PL based on the measured value (that is, the surface position information of the wafer table WTB)The offset of the representative detection point of the position (the detection point located at the center or in the vicinity thereof among the plurality of detection points at this time) is adjusted by, for example, an optical method so that the detection origin of the multipoint AF system becomes zero.

In this case, from the viewpoint of improving the throughput, only one of the second half process of the Pri-BCHK and the second half process of the focus correction may be performed, or the process may be shifted to the next process without performing both processes. Of course, if the second half of the Pri-BCHK process is not performed, that is, the first half of the Pri-BCHK process is not necessarily performed, main controller 20 may move wafer stage WST to a position where the alignment mark provided on first alignment irradiation area AS can be detected from loading position LP. When the Pri-BCHK process is not performed, a baseline measured immediately before exposure of the wafer before the exposure target wafer W in the same operation is used. In the latter half of the focus correction, the best focus position of the projection optical system PL measured immediately before the previous exposure of the wafer is used, as in the case of the base line.

In the state of fig. 24, the focus correction is continued.

When both stages WST and MST in the contact state (or the close state) are moved in the + Y direction and wafer stage WST reaches the position shown in fig. 25 after a predetermined time, main control device 20 stops wafer stage WST at the position and continues to move measurement stage MST in the + Y direction. Next, the master control device 20 uses five alignment systems AL1, AL2₁～AL2₄The alignment marks (see the star marks in fig. 25) attached to the five third alignment irradiation regions are detected substantially simultaneously and independently, and the five alignment systems AL1 and AL2 are used₁～AL2₄The detection result of (b) and the measured values of at least three encoders (measured values corrected by the correction information) among the four encoders at the time of the detection are stored in the internal memory so as to be associated with each other. At this time, focus matching is also continued.

On the other hand, after a predetermined time has elapsed from the stop of wafer stage WST, measurement stage MST and wafer stage WST move from the contact (or close state) to the separation state. After moving to the separated state, main controller 20 stops measurement stage MST at an exposure start standby position where it is standby until the exposure is started.

Next, main controller 20 moves wafer stage WST in the + Y direction to the detection positions of the alignment marks attached to the three first alignment irradiation areas. The focus matching is continued at this time. On the other hand, wafer stage WST is waiting at the exposure start standby position.

Next, when wafer stage WST reaches the position shown in fig. 26, main control apparatus 20 immediately stops wafer stage WST and uses primary alignment system AL1 and secondary alignment system AL2₂,AL2₃The alignment marks (see the star marks in fig. 26) attached to the three first alignment shot regions on the wafer W are detected substantially simultaneously and independently, and the three alignment systems AL1 and AL2 are used₂,AL2₃And the measured values of at least one of the four encoders at the time of the detection are stored in the internal memory in a manner correlated with each other. At this point, focus matching is continued, and measurement stage MST is kept waiting at the exposure start standby position. Next, the main controller 20 calculates arrangement information (coordinate values) of all the irradiated regions on the wafer W on a coordinate system (XY coordinate system with the center of the wafer table WTB as the origin) defined by the measurement axes of the four encoders by using the detection results of the sixteen alignment marks obtained in the above-described manner and the measurement values of the corresponding encoders (measurement values corrected by the correction information described above) via, for example, the EGA method disclosed in U.S. patent No. 4,780,617 specification.

Next, main control device 20 continues focus matching while moving wafer stage WST in the + Y direction again. Next, when the detection light beams from the multi-spot AF systems (90a,90b) deviate from the surface of the wafer W, the focus matching is ended as shown in FIG. 27. Thereafter, main control device 20 performs wafer alignment (EGA) based on the results of the prior wafer alignment and five alignment systems AL1, AL2₁～AL2₂The latest baseline measurement result and the like are sequentially transferred to a plurality of shot areas on the wafer W by performing step-and-scan type exposure through immersion exposure. Thereafter, the same operation is repeated for the remaining wafers in the lot to expose them.

Note that, although the main control device 20 has been set to control each part of the exposure apparatus such as the stage system for the sake of simplicity of explanation, the present invention is not limited to this, and it goes without saying that at least a part of the control performed by the main control device 20 may be shared by a plurality of control devices. For example, a stage control device that controls wafer stage WST and the like based on the measurement values of the encoder system, the Z sensor, and the interferometer system may be provided under the control of main control device 20. The control by the main controller 20 is not necessarily implemented by hardware, but may be implemented by software using a computer program for specifying the operation of each of the main controller 20 or the plurality of controllers that share the control.

As described above in detail, according to exposure apparatus 100 of the present embodiment, when wafer stage WST is moved in a predetermined direction, for example, the Y-axis direction during alignment of a wafer or during exposure, wafer stage WST is driven in the Y-axis direction based on measurement information of the encoder system and positional information (including tilt information, for example, rotation information in the θ x direction) of wafer stage WST in a direction different from the Y-axis direction. That is, wafer stage WST is driven to compensate for measurement errors of the encoder system (encoders 70A,70C) caused by displacement (including tilt) of wafer stage WST in a direction different from the Y-axis direction and the scale. In the present embodiment, main control device 20 uses the measurement values of encoders 70A,70C for measuring positional information of wafer stage WST in the Y-axis direction, and positional information of wafer stage WST in a direction (non-measurement direction) different from the Y-axis direction at the time of the measurement (for example, positional information measured by Y interferometer 16 and Z interferometers 43A,43B of interferometer system 118 with respect to waferStage position induced error correction information (correction information calculated by the above equation (10)) corresponding to the position information of the stage WST in the θ x direction, the θ Z direction, and the Z axis direction drives the wafer stage WST in the Y axis direction. Thus, the scale 39Y can be adjusted₁、39Y₂Encoders 70A,70C that are displaced relative to Y head 64 in the non-measurement direction measure errors, and control stage drive system 124 so as to drive wafer stage WST in the Y-axis direction.

When wafer stage WST is moved in the X-axis direction, wafer stage WST is driven in the X-axis direction based on the measurement information of the encoder system and the positional information of wafer stage WST in a direction different from the X-axis direction (including tilt information, for example, rotation information in the θ y direction). That is, wafer stage WST is driven to compensate for measurement errors of the encoder systems (encoders 70B,70D) caused by displacement (including tilt) of wafer stage WST in a direction different from the X-axis direction. In the present embodiment, wafer stage WST is driven in the X-axis direction by main control device 20 based on the measurement values of encoders 70B,70D for measuring positional information of wafer stage WST in the X-axis direction, and positional information of wafer stage WST in a direction (non-measurement direction) different from the X-axis direction at the time of the measurement (for example, stage position induced error correction information (correction information calculated by equation (11)) corresponding to positional information of wafer stage WST in the θ y direction, the θ Z direction, and the Z-axis direction measured by interferometer systems 118Z interferometers 43A, 43B). Therefore, wafer stage WST can be driven in a desired direction with good accuracy using the encoder without being affected by relative movement between the head and the scale in a direction other than the desired measurement direction (measurement direction).

Further, according to exposure apparatus 100 of the present embodiment, in order to move illumination light IL emitted from illumination system 10 to wafer W via reticle R, projection optical system PL, and water Lq relative to wafer W, main controller 20 drives wafer stage WST on which wafer W is mounted with good accuracy based on the measurement values of the above-described encoders and positional information of wafer stage WST in a non-measurement direction at the time of measurement. Therefore, the pattern of the reticle R can be formed on the wafer with good accuracy by the scanning exposure and the liquid immersion exposure.

Further, according to the present embodiment, when acquiring correction information of the measurement value of the encoder, main controller 20 changes wafer stage WST to a plurality of different postures, and while maintaining the posture of wafer stage WST based on the measurement result of interferometer measurement system 118 for each posture, detects light from heads 64 and 66 of the encoder to scale 39Y₁、39Y₂,39X₁、39X₂While moving wafer stage WST in the Z-axis direction within a predetermined movement range, the specific area of (b) samples the measurement result of the encoder during the movement. In this way, information on the change in the encoder measurement value (for example, a characteristic curve shown in the graph of fig. 12) corresponding to the position of wafer stage WST in the direction (Z-axis direction) perpendicular to the moving surface for each posture is obtained.

Next, main controller 20 performs a predetermined calculation based on the sampling result, that is, information on the change in the encoder measurement value corresponding to the position of wafer stage WST in the Z-axis direction in each posture, to thereby obtain correction information on the encoder measurement value corresponding to the position information of wafer stage WST in the non-measurement direction. Therefore, correction information for correcting an encoder measurement error caused by a relative change between the head and the scale in the non-measurement direction can be determined by a simple method.

In the present embodiment, when the correction information is determined for a plurality of heads constituting the same head unit, for example, a plurality of Y heads 64 constituting head unit 62A, the detection light is irradiated from each Y head 64 to the corresponding Y scale 39Y₁The measurement result of the encoder is sampled, and based on the sampling result, the Y head 64 and the Y scale 39Y are determined₁The stage position-induced error correction information of each encoder is configured so that the geometric error caused by the head tilt can be also corrected by using the correction information. In other words, the main controller 20 obtains the correction for a plurality of encoders corresponding to the same scaleIn the case of information, the correction information of the target encoder is obtained in consideration of a geometric error caused by the tilt of the head of the target encoder when wafer stage WST is moved in the Z-axis direction. Therefore, in the present embodiment, cosine errors due to differences in the tilt angles of the plurality of heads do not occur, and even when Y head 64 does not tilt and measurement errors occur in the encoder due to, for example, the optical characteristics (inclination, etc.) of the heads, the correction information can be obtained in the same manner to prevent the occurrence of measurement errors, and thus prevent the accuracy of position control of wafer stage WST from being lowered. That is, in the present embodiment, wafer stage WST is driven to compensate for a measurement error of the encoder system caused by the head unit (hereinafter also referred to as a head-induced error). Further, for example, measurement value correction information of the encoder system may be calculated based on characteristic information of the head unit (including, for example, inclination of the head and/or optical characteristics). In the present embodiment, the stage position-induced error and the head-induced error may be corrected individually.

The configurations and arrangements of the encoder system, interferometer system, multi-point AF system, Z sensor, and the like according to the above embodiments are merely examples, and the present invention is not limited to these. For example, in the above embodiment, the pair of Y heads 39Y for measuring the Y-axis direction position are used₁,39Y₂And a pair of X heads 39X for measuring the position in the X-axis direction₁,39X₂And a pair of head units 62A,62C disposed on one side and the other side in the X-axis direction of projection optical system PL and a pair of head units 62B,62D disposed on one side and the other side in the Y-axis direction of projection optical system PL, respectively, provided on wafer table WTB, however, the present invention is not limited to this, and Y head 39Y for Y-axis direction position measurement may be used₁,39Y₂And an X head 39X for measuring the position in the X-axis direction₁,39X₂At least one (not a pair) of the head units is provided on wafer table WTB, or only one of the pair of head units 62A,62C and at least one of the pair of head units 62B,62D is provided. The extending direction of the scale and the extending direction of the head unit are not limited to the X-axis of the above-described embodimentsThe direction and the direction orthogonal to the Y-axis direction may be directions intersecting each other. In this case, the plurality of heads of the corresponding head unit may be arranged in a direction orthogonal to the diffraction grating periodic direction. Each head unit may have a plurality of heads disposed without a gap in a direction orthogonal to the diffraction grating period direction.

In the above-described embodiment, the encoder system is configured such that the grating portion (X scale, Y scale) is disposed on the wafer stage (wafer stage) and the head units (X head, Y head) are disposed outside the wafer stage so as to face the grating portion, but the encoder system is not limited to this configuration, and may be configured such that the encoder head is disposed on the wafer stage (wafer stage) and the two-dimensional grating (or the one-dimensional grating portion disposed two-dimensionally) is disposed outside the wafer stage so as to face the grating portion. In this case, when the Z sensor is also arranged on the upper surface of the wafer stage, the two-dimensional grid (or the two-dimensionally arranged one-dimensional grid portion) can be used as a reflection surface for reflecting the measurement beam from the Z sensor. Even if the encoder system having such a configuration is employed, basically, as in the above-described embodiment, wafer stage WST can be driven in the measurement direction of the encoder based on information on the flatness of the scale and the measurement value of the encoder. Thus, wafer stage WST can be driven in a desired direction with good accuracy using the encoder without being affected by the unevenness of the scale.

In the above-described embodiment, the rotation information (pitch amount) of wafer stage WST in the θ x direction is measured by the interferometer system, but it may be measured by a pair of Z sensors 74, for example_i,jOr 76_p,qThe pitch is determined from the measured values of (2). Alternatively, similarly to the head units 62A and 62C, for example, one or a pair of Z sensors may be arranged near each head of the head units 62B and 62D, and the Z sensors may be arranged on the X scale 39X₁,39X₂The pitch amounts are obtained from the respective measurements of the facing Z sensors. Thus, it is possible to measure the direction of six degrees of freedom, that is, the X-axis of wafer stage WST using the encoder and the Z sensor, without using interferometer system 118Y-axis, Z-axis, θ x, θ Y, and θ Z-direction position information. The operation of the encoder and the Z sensor to measure the positional information of wafer stage WST in the six-degree-of-freedom direction may be performed not only in the exposure operation but also in the alignment operation and/or the focus matching operation.

In the above-described embodiment, the measurement value of the encoder system is corrected based on the correction information to compensate for the measurement error of the encoder system caused by the displacement of wafer stage WST in a direction different from the predetermined direction in which wafer stage WST is driven (the relative displacement between the head and the scale), but the present invention is not limited to this, and for example, the target position for positioning wafer stage WST may be corrected based on the correction information while wafer stage WST is driven based on the measurement value of the encoder system. Alternatively, particularly during the exposure operation, the position of reticle stage RST may be corrected based on the correction information while wafer stage WST is driven based on the measurement values of the encoder system.

In the above-described embodiment, only wafer stage WST is driven based on the measurement values of the encoder system, for example, during exposure, but for example, an encoder system for measuring the position of reticle stage RST may be added, and reticle stage RST may be driven based on the measurement values of the encoder system and correction information corresponding to the position information of reticle stage in the non-measurement direction measured by reticle interferometer 116.

In the above-described embodiment, the alignment marks of sixteen alignment irradiation areas attached to the wafer are detected by the strokes corresponding to the five alignment systems, while one fixed primary alignment system and four movable secondary alignment systems are provided. However, the secondary alignment system may not be movable, and in addition, the number of secondary alignment systems may be arbitrary. In general, there may be at least one alignment system capable of detecting alignment marks on the wafer.

In the above-described embodiment, although an exposure apparatus including measurement stage MST separately and independently from wafer stage WST has been described as in the exposure apparatus disclosed in, for example, WO2005/074014 pamphlet or the like, the present invention is not limited to this, and even in the exposure apparatus of the two-wafer stage system in which exposure operation and measurement operation (for example, detection of a mark by an alignment system) are performed substantially simultaneously using two wafer stages, the position of each wafer stage can be controlled using the aforementioned encoder system (see fig. 3 and the like), as disclosed in, for example, japanese patent laid-open No. 10-214783 pamphlet and U.S. Pat. No. 6,341,007, and international publication No. 98/40791 pamphlet and U.S. Pat. No. 6,262,796 or the like. Here, the position of each wafer stage may be controlled by directly using the encoder system by appropriately setting the arrangement, length, and the like of each head unit not only during the exposure operation but also during the measurement operation, but the head units that can be used for the measurement operation may be provided separately from the head units (62A to 62D). For example, four head units arranged in a cross shape with one or two alignment systems as the center may be provided, and the positional information of each wafer stage WST may be measured by these head units and the corresponding movement scales (62A to 62D) during the measurement operation. In the exposure device of the double-wafer stage system, at least two moving scales are provided on each of the two wafer stages, and after the exposure operation of the wafer mounted on one wafer stage is completed, the other wafer stage for mounting the next wafer having been mark-detected at the measurement position is arranged at the exposure position by replacement with the one wafer stage. The measurement operation performed simultaneously with the exposure operation is not limited to the detection of the mark of the wafer or the like by the alignment system, and the detection of the surface position information (step information or the like) of the wafer may be performed instead of this method or in combination with this method.

In the above-described embodiment, while the wafer stage WST side is being replaced with a wafer, Sec-BCHK (time interval) is performed using CD lever 46 of measurement stage MST, but the present invention is not limited to this, and at least one of illuminance unevenness measurement (and illuminance measurement), aerial image measurement, wavefront aberration measurement, and the like may be performed using a measurement device (measurement means) of measurement stage MST, and the measurement result may be reflected in wafer exposure performed thereafter. Specifically, for example, the adjustment of the projection optical system PL can be performed by the adjustment device 68 based on the measurement result.

In the above embodiment, a scale may be disposed on the measurement stage MST, and the encoder system (head unit) may be used to control the position of the measurement stage. That is, the moving body that measures the positional information by the encoder system is not limited to the wafer stage.

Further, in consideration of downsizing, weight reduction, and the like of wafer stage WST, it is preferable to arrange the scale as close as possible to wafer W on wafer stage WST, but when the wafer stage size can be increased, the wafer stage may be increased so as to increase the interval between the pair of scales arranged in opposition to each other, whereby two pieces of positional information, or four pieces of positional information in total, can be measured in the X-axis direction and the Y-axis direction at any time at least during the exposure operation of the wafer. Alternatively, instead of increasing the size of the wafer stage, the distance between a pair of similarly opposed scales may be increased by providing the scale such that a part thereof protrudes from the wafer stage, or by disposing the scale outside the wafer stage main body using an auxiliary plate provided with at least one scale.

In the above embodiment, the scale 39Y is designed to prevent foreign matter from adhering to the scale₁,39Y₂X scale 39X₁,39X₂Or contamination, etc., causes a decrease in measurement accuracy, and for example, the surface may be coated to cover at least the diffraction grating, or a cover glass may be provided. In this case, in particular, in the liquid immersion type exposure apparatus, a liquid-repellent protective film may be applied to the scale (grid surface) or a liquid-repellent film may be formed on the surface (upper surface) of the cover glass. Further, although the diffraction grating is continuously formed in substantially the entire area of each scale in the longitudinal direction, the diffraction grating may be intermittently formed by dividing the diffraction grating into a plurality of areas, or each moving scale may be constituted by a plurality of scales. In the above-described embodiment, the encoder using the diffraction interference method is exemplified as the encoder, but the present invention is not limited thereto, and a so-called pickup method, a magnetic method, or the like may be used, for example, as disclosed in U.S. Pat. No. 6,639,686 specification or the likeSo-called scan encoders, etc.

In the above-described embodiment, instead of the optical pickup sensor, a sensor having, for example, the following configuration, that is, a Z sensor may be used: for example, a 1 st sensor (which may be an optical pickup type sensor or another optical type displacement sensor) that projects a probe beam onto a measurement target surface and receives reflected light thereof to optically read a displacement of the measurement target surface in the Z-axis direction, a driving unit that drives the 1 st sensor in the Z-axis direction, and a 2 nd sensor (for example, an encoder or the like) that measures a displacement of the 1 st sensor in the Z-axis direction. In the Z sensor having such a configuration, a mode (1 st servo control mode) in which the 1 st sensor is driven in the Z axis direction by the driving unit based on the output of the 1 st sensor so that the distance between the surface to be measured, for example, the surface of the scale, and the 1 st sensor in the Z axis direction is constant, and a mode (2 nd servo control mode) in which a target value given to the 2 nd sensor from the outside (control device) is maintained and the driving unit maintains the position of the 1 st sensor in the Z axis direction so that the measurement value of the 2 nd sensor matches the target value can be set. In the 1 st servo control mode, the output of the Z sensor may be the output of the measuring unit (2 nd sensor), and in the 2 nd servo control mode, the output of the 2 nd sensor may be used. In the case of using the Z sensor described above, when an encoder is used as the 2 nd sensor, the encoder can be used to measure positional information of wafer stage WST (wafer table WTB) in the six-degree-of-freedom direction. In the above embodiments, a sensor of another detection system may be used as the Z sensor.

In the above-described embodiment, the configuration or combination of the plurality of interferometers for measuring the positional information of wafer stage WST is not limited to the above-described configuration or combination. In short, the configuration and combination of the interferometers can be arbitrary as long as the positional information of wafer stage WST in a direction other than the measurement direction of the encoder system can be measured. In addition to the encoder system described above, a measuring device (whether or not it is an interferometer) capable of measuring positional information of wafer stage WST in a direction other than the measurement direction of the encoder system may be provided. For example, the Z sensor may be used as a measuring device.

In the above embodiment, the Z sensor is provided in addition to the multipoint AF system, but the measurement Z sensor is not necessarily provided as long as the multipoint AF system can detect the surface position information of the wafer W in the exposure target irradiation region at the time of exposure.

In the above-described embodiment, pure water (water) is used as the liquid, but the present invention is not limited to this. A safety liquid having stable chemical properties and high transmittance of the illumination light IL may be used as the liquid, for example, a fluorine-based inert liquid. As the fluorine-based inert liquid, for example, floriant (trade name of 3M company, usa) can be used. The fluorine-based inert liquid also has an excellent cooling effect. As the liquid, a liquid having a refractive index higher than that of pure water (refractive index of about 1.44), for example, a refractive index of 1.5 or more, for the illumination light IL may be used. Examples of such a liquid include isopropyl alcohol having a refractive index of about 1.50, a predetermined liquid having a C-H bond or an O-H bond such as glycerin having a refractive index of about 1.61, a predetermined liquid (organic solvent) such as hexane, heptane or decane, Decahydronaphthalene (Decahydronaphthalene) having a refractive index of about 1.60, and the like. Alternatively, any two or more of the above liquids may be mixed, or at least one of the above liquids may be added (mixed) to pure water. Alternatively, the liquid LQ may be prepared by adding (mixing) H to pure water⁺、Cs⁺、K⁺、Cl^-、SO₄ ^2-、PO₄ ^2-And the like bases and acids. Further, fine particles of Al oxide or the like may be added (mixed) to the pure water. The liquid can transmit ArF excimer laser. Further, it is preferable that the liquid has a small absorption coefficient of light and a small temperature dependency, and is stable against a photosensitive material (or a protective film (top coating film), an antireflection film, or the like) applied to the projection optical system PL and/or the wafer surface. In addition, in the formula F₂When laser is used as the light source, the perfluoropolyether Oil (Fomblin Oil) is selected.

In the above embodiment, the recovered liquid may be reused, and in this case, it is preferable that a filter for removing impurities from the recovered liquid be provided in the liquid recovery device, the recovery pipe, or the like.

In the above-described embodiment, the case where the exposure apparatus is a liquid immersion type exposure apparatus has been described, but the present invention is not limited to this, and is also suitably applied to a dry exposure apparatus which exposes the wafer W without passing a liquid (water).

In the above-described embodiments, the present invention has been described as being applied to a scanning exposure apparatus such as a step-and-scan system, but the present invention is not limited thereto, and the present invention can also be applied to a stationary exposure apparatus such as a stepper. Even in a stepper or the like, the position of the stage on which the exposure target object is mounted can be measured by the encoder, and the possibility of occurrence of a position measurement error due to air turbulence can be made almost zero in the same manner. In this case, the stage can be positioned with high accuracy based on the measurement value of the encoder and the correction information, and as a result, the reticle pattern with high accuracy can be transferred to the object. The present invention is also applicable to a reduction projection exposure apparatus of a step-and-join method for combining an irradiation field and an irradiation field, an exposure apparatus of a proximity method, a mirror projection alignment exposure apparatus, and the like.

The projection optical system in the exposure apparatus according to the above embodiment may be not only a reduction system but also an equal magnification system or an enlargement system, and the projection optical system PL may be not only a refraction system but also a reflection system or a catadioptric system, and the projection image may be an inverted image or an erect image. Further, although the exposure region IA on which the illumination light IL is irradiated via the projection optical system PL is an on-axis region including the optical axis AX in the field of view of the projection optical system PL, for example, as in the case of the so-called on-line type catadioptric system disclosed in wo 2004/107011, the exposure region may be an off-axis region not including the optical axis AX, and the on-line type catadioptric system may have a plurality of reflection surfaces, and an optical system (reflection system or catadioptric system) forming at least one intermediate image provided in a part thereof, and may have a single optical axis. The illumination area and the exposure area are rectangular in shape, but the shape is not limited to this, and may be, for example, circular arc, trapezoid, or parallelogram.

The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser source, and a KrF excimer laser source (output wavelength 248nm) or F can be used₂Laser (output wavelength 157nm), Ar₂Laser (output wavelength 126nm), Kr₂A pulsed laser source such as a laser (output wavelength 146nm), or an ultra-high pressure mercury lamp that emits bright light such as g-line (wavelength 436nm) or i-line (wavelength 365 nm). Further, a harmonic generator of YAG laser or the like may be used. Further, for example, a single wavelength laser beam in the infrared region or the visible region emitted from a DFB semiconductor laser or a fiber laser can be amplified as a vacuum ultraviolet light by using a fiber amplifier coated with erbium (or both erbium and ytterbium) using a harmonic wave disclosed in international publication No. 1999/46835 pamphlet (corresponding to U.S. patent No. 7,023,610), and converted into an ultraviolet light by a nonlinear optical crystal.

In the above embodiment, the illumination light IL of the exposure apparatus is not limited to light having a wavelength of more than 100nm, and light having a wavelength of less than 100nm may be used. For example, in recent years, in order to expose a pattern of 70nm or less, an EUV exposure apparatus has been developed which generates EUV (extreme Ultra violet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm) using an SOR or a plasma laser as a light source, and uses a total reflection reduction optical system and a reflection type mask designed according to an exposure wavelength (for example, 13.5nm) thereof. The apparatus is constructed to scan and expose the mask and the wafer by using the arc illumination and the synchronous scanning, so that the present invention can be suitably applied to the apparatus. The present invention is also applicable to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

In the above-described embodiments, a light transmissive mask (reticle) is used in which a predetermined light shielding pattern (or phase pattern, or dimming pattern) is formed on a light transmissive substrate, but an electronic mask (also referred to as a variable-shape mask, an active mask, or an image generator, such as a DMD (Digital Micro-mirror Device) including a non-light-emitting image display Device (spatial light modulator)) that forms a transmission pattern, a reflection pattern, or a light-emitting pattern from electronic data of a pattern to be exposed may be used instead of this mask, as disclosed in, for example, U.S. Pat. No. 6,778,257. When such a variable shape mask is used, since the stage on which the wafer, the cover glass, or the like is mounted scans the variable shape mask, the position of the stage can be measured using the encoder, and the stage can be driven based on the measurement value of the encoder and correction information corresponding to the positional information of the stage in the non-measurement direction measured by the interferometer, thereby obtaining the same effect as in the above-described embodiment.

The present invention is also applicable to an exposure apparatus (lithography system) that forms a pattern of equal-pitch lines on a wafer by forming interference fringes on the wafer, as disclosed in, for example, international publication No. 2001/035168.

Further, for example, the present invention can be applied to an exposure apparatus disclosed in japanese unexamined patent application publication No. 2004-519850 (corresponding to U.S. patent No. 6,611,316), in which two reticle patterns are synthesized on a wafer via a projection optical system, and double exposure is performed on one shot region on the wafer substantially simultaneously by one scanning exposure.

The apparatus for forming a pattern on an object is not limited to the exposure apparatus (lithography system), and the present invention can be applied to an apparatus for forming a pattern on an object by an inkjet method, for example.

In the embodiments and modifications described above, the object to be patterned (the object to be exposed to the energy beam) is not limited to a wafer, and may be another object such as a glass plate, a ceramic substrate, a film member, or a mask substrate.

The use of the exposure apparatus is not limited to exposure apparatuses for semiconductor manufacturing, and the apparatus can be widely applied to, for example, an exposure apparatus for manufacturing liquid crystal for transferring a liquid crystal display device pattern to a square glass plate, an exposure apparatus for manufacturing organic EL, a thin film magnetic head, an image pickup device (such as CCD), a micromachine, a DNA chip, and the like. In addition to the production of microdevices such as semiconductor devices, the present invention can be applied to an exposure apparatus for transferring a circuit pattern onto a glass substrate, a silicon wafer, or the like in order to produce a reticle or a mask used for a light exposure apparatus, an EUV (extreme ultraviolet) exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, or the like.

The moving body driving system, the moving body driving method, or the determining method according to the present invention is not limited to the exposure apparatus, and can be widely applied to other substrate processing apparatuses (for example, other apparatuses such as a laser repair apparatus and a substrate inspection apparatus), and other apparatuses having a moving body such as a stage that moves in a two-dimensional plane, such as a sample positioning apparatus and a wire bonding apparatus in a precision machine.

The exposure apparatus (patterning apparatus) according to the above embodiment is manufactured by assembling various subsystems (including the respective components listed in the scope of the present application) so as to maintain predetermined mechanical, electrical, and optical accuracy. To ensure these various accuracies, before and after assembly, adjustment for achieving optical accuracy is performed for various optical systems, adjustment for achieving mechanical accuracy is performed for various mechanical systems, and adjustment for achieving electrical accuracy is performed for various electrical systems. The steps of assembling the various subsystems to the exposure apparatus include mechanical connection, wiring connection of circuits, piping connection of pneumatic circuits, and the like. Of course, there are individual assembly steps for each subsystem before the assembly steps from the various subsystems to the exposure apparatus. When the assembly steps from various subsystems to the exposure device are finished, the comprehensive adjustment is carried out to ensure various accuracies of the whole exposure device. Further, it is preferable that the exposure apparatus is manufactured in a clean room in which temperature, cleanliness, and the like are controlled.

The disclosures of all publications, international pamphlets, U.S. patent application publications, and U.S. patent applications relating to exposure apparatuses and the like cited in the above embodiments are incorporated herein by reference.

Next, an embodiment of a device manufacturing method using the exposure apparatus (patterning apparatus) in the photolithography step will be described.

Fig. 28 is a flowchart showing an example of manufacturing a package (a semiconductor chip such as an IC (integrated circuit) or an LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, or the like). As shown in fig. 28, first, in step 201 (designing step), function/performance design of a device (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Next, in step 202 (mask making step), a mask on which the designed circuit pattern is formed is made. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), the mask and the wafer prepared in steps 201 to 203 are used, and as described later, actual circuits and the like are formed on the wafer by photolithography or the like. Next, in step 205 (component assembly step), component assembly is performed using the wafer processed in step 204. In step 205, a dicing step, a bonding step, a packaging step (chip encapsulation) and the like are included as necessary.

Finally, in step 206 (inspection step), an inspection such as an operation confirmation test and an endurance test is performed on the component manufactured in step 205. After these steps the assembly is completed and unloaded.

Fig. 29 shows a detailed flowchart of step 204 in the case of a semiconductor device. In fig. 29, step 211 (oxidation step) oxidizes the wafer surface. Step 212 (CVD) forms an insulating film on the wafer surface. Step 213 (electrode forming step) forms an electrode on the wafer by evaporation. Step 214 (ion implantation step) implants ions into the wafer. Each of the steps 211 to 214 constitutes a preprocessing step of each stage of the wafer processing, and is selected and executed depending on the processing required for each stage.

When the pretreatment step is completed in each stage of the wafer treatment, the post-treatment step is performed as follows. In the next process step, first, in step 215 (resist formation step), a photosensitizer is applied to the wafer. Next, in step 216 (exposure step), the circuit pattern of the mask is transferred to the wafer using the exposure apparatus (patterning apparatus) and the exposure method (patterning method) described above. Next, in step 217 (developing step), the exposed wafer is developed, and in step 218 (etching step), the exposed member except for the remaining portion of the resist is removed by etching. Next, in step 219 (resist removal step), unnecessary resist after the end of etching is removed.

By repeating these pre-processing steps and post-processing steps, a multi-circuit pattern is formed on the wafer.

When the device manufacturing method of the present embodiment described above is used, the exposure apparatus (patterning apparatus) and the exposure method (patterning method) of the above-described embodiments are used in the exposure step (step 216), and thus exposure can be performed with high productivity while maintaining high overlay accuracy. Thus, the productivity of a highly integrated module in which a fine pattern is formed can be improved.

As described above, the moving body drive system and the moving body drive method according to the present invention are suitable for driving a moving body in a moving plane. The pattern forming apparatus and the pattern forming method of the present invention are suitable for forming a pattern on an object. The exposure apparatus, the exposure method, and the device manufacturing method according to the present invention are suitable for manufacturing a microdevice. The determining method of the present invention is suitable for determining correction information of an encoder measurement value for measuring position information of a moving body in a predetermined direction in the moving plane.

Claims (22)

1. An exposure method for exposing a substrate with illumination light through a projection optical system, comprising:

an operation of measuring position information of the stage by a plurality of heads facing the grid portion of an encoder system in which one of the grid portion and the heads is provided on the stage on which the substrate is mounted and the other of the grid portion and the heads is provided outside the stage;

controlling the operation of driving the stage in one direction based on the measured position information and correction information for compensating a measurement error of the encoder system caused by relative movement between the head and the grating part in a direction different from one of 1 st and 2 nd directions orthogonal to each other in a predetermined plane perpendicular to the optical axis of the projection optical system;

switching 1 of the plurality of heads used for the measurement to the operation of the other heads during the movement of the stage;

after the switching, the position information of the stage is measured by including the remaining head excluding the 1 head among the plurality of heads and the plurality of heads of the other heads.

2. The exposure method according to claim 1, wherein:

before the switching, the position information of the stage is measured by the 3 heads facing the grating portion, and after the switching, the position information of the stage is measured by the 3 heads including 2 heads excluding the 1 head among the 3 heads and the other heads different from the 3 heads.

3. The exposure method according to claim 2, wherein:

the switching from the 1 head to the other heads is performed while the 3 heads including the head used before the switching and the 4 heads including the other heads face the grating portion.

4. The exposure method according to claim 3, wherein:

the 3 or 4 heads of the encoder system face the grating portion, and the head facing the grating portion is changed from one of the 3 heads and the 4 heads to the other head by the movement of the stage.

5. The exposure method according to claim 3, wherein:

the grating part has 4 scale members each forming a reflection grating,

the position information of the stage is measured by 3 or 4 heads arranged to face 3 or 4 of the 4 scale members, respectively.

6. The exposure method according to any one of claims 1 to 5, wherein:

the different directions include at least 1 of a 3 rd direction orthogonal to the 1 st and 2 nd directions, a rotational direction around an axis orthogonal to the predetermined plane, and a rotational direction around an axis parallel to the predetermined plane.

7. The exposure method according to any one of claims 1 to 5, wherein:

a nozzle unit surrounding a lower end portion of the projection optical system, a liquid immersion area formed with a liquid under the projection optical system, and the substrate exposed to the illumination light through the projection optical system and the liquid immersion area,

the other of the grid part and the head is provided outside the nozzle unit with respect to the projection optical system.

8. The exposure method according to claim 7, wherein:

the stage holds the substrate in a recess on an upper surface thereof such that a surface of the substrate is substantially flush with the upper surface.

9. The exposure method according to claim 8, wherein:

the encoder system measures positional information of the stage in a 6-degree-of-freedom direction including the 1 st and 2 nd directions and a 3 rd direction orthogonal to the 1 st and 2 nd directions.

10. The exposure method according to claim 9, wherein:

the stage is provided with the head and moves below the grating portion during the exposure operation.

11. A method of manufacturing a component, comprising:

an operation of exposing the substrate by using the exposure method according to any one of claims 1 to 10;

and developing the exposed substrate.

12. An exposure apparatus for exposing a substrate with illumination light through a projection optical system, comprising:

a stage on which the substrate is placed;

an encoder system in which one of a grating portion and a head is provided on the stage and the other of the grating portion and the head is provided outside the stage, and position information of the stage is measured by the plurality of heads facing the grating portion;

a control device for controlling the driving of the stage in one direction based on correction information for compensating a measurement error of the encoder system caused by relative movement between the head and the grating part in a direction different from one of 1 st and 2 nd directions orthogonal to each other in a predetermined plane perpendicular to an optical axis of the projection optical system and the measured position information;

switching 1 of the plurality of heads used for the measurement to another head during the movement of the stage,

after the switching, the position information of the stage is measured by including the remaining head excluding the 1 head among the plurality of heads and the plurality of heads of the other heads.

13. The exposure apparatus according to claim 12, wherein:

before the switching, the position information of the stage is measured by the 3 heads facing the grating portion, and after the switching, the position information of the stage is measured by the 3 heads including 2 heads excluding the 1 head among the 3 heads and the other heads different from the 3 heads.

14. The exposure apparatus according to claim 13, wherein:

the switching from the 1 head to the other heads is performed while the 3 heads including the head used before the switching and the 4 heads including the other heads face the grating portion.

15. The exposure apparatus according to claim 14, wherein:

in the encoder system, 3 or 4 heads are opposed to the grating portion, and the head opposed to the grating portion is changed from one of the 3 heads and the 4 heads to the other by the movement of the stage.

16. The exposure apparatus according to claim 14, wherein:

the grating part has 4 scale members each forming a reflection grating,

the position information of the stage is measured by 3 or 4 heads arranged to face 3 or 4 of the 4 scale members, respectively.

17. The exposure apparatus according to any one of claims 12 to 16, wherein:

the different directions include at least 1 of a 3 rd direction orthogonal to the 1 st and 2 nd directions, a rotational direction around an axis orthogonal to the predetermined plane, and a rotational direction around an axis parallel to the predetermined plane.

18. The exposure apparatus according to any one of claims 12 to 16, further comprising:

a local immersion device having a nozzle unit surrounding a lower end portion of the projection optical system and forming an immersion area with a liquid under the projection optical system,

the substrate is exposed to the illumination light through the projection optical system and the liquid in the liquid immersion area,

the other of the grid part and the head is provided outside the nozzle unit with respect to the projection optical system.

19. The exposure apparatus according to claim 18, wherein:

the stage holds the substrate in a recess on an upper surface thereof such that a surface of the substrate is substantially flush with the upper surface.

20. The exposure apparatus according to claim 19, wherein:

the encoder system measures positional information of the stage in a 6-degree-of-freedom direction including the 1 st and 2 nd directions and a 3 rd direction orthogonal to the 1 st and 2 nd directions.

21. The exposure apparatus according to claim 20, wherein:

the stage is provided with the head and moves below the grating portion during the exposure operation.

22. A method of manufacturing a component, comprising:

an operation of exposing a substrate by using the exposure apparatus according to any one of claims 12 to 21;

and developing the exposed substrate.