JPH11260706A - Illuminance meter, illuminance measuring method and exposure apparatus - Google Patents

Abstract

An object of the present invention is to simplify the work of measuring the illuminance of illumination light of an exposure apparatus and reduce the time required for illuminance measurement. SOLUTION: A wafer-type illuminometer 50 in which an optical sensor 52 is integrally provided on a dummy wafer 51 formed in a thin plate so as to be able to be conveyed similarly to a wafer to be exposed is used between a plurality of exposure apparatuses. The illuminometer 50 is sequentially loaded and unloaded onto and from the wafer stage similarly to the wafer, and the illuminance of the illumination light in the vicinity of the image plane of the projection optical system of each exposure apparatus is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminometer, an illuminance measuring method, and an exposure apparatus, and more particularly, to an illuminometer and an illuminance used for measuring relative illuminance among a plurality of exposure apparatuses. The present invention relates to a measurement method and an exposure apparatus.

[0002]

2. Description of the Related Art When manufacturing a semiconductor device, a liquid crystal display device, or the like, a mask or a reticle (hereinafter referred to as a "mask") is used.
For example, a projection exposure apparatus is used to transfer a pattern drawn on an original such as a semiconductor wafer or a transparent substrate coated with a resist. In a production line for a semiconductor device, a liquid crystal display device, or the like, not only a single projection exposure apparatus is used, but generally, a plurality of projection exposure apparatuses are used in combination.

In such a case, it is necessary to match the exposure amount between the respective exposure apparatuses in order to reduce variations in products manufactured by the respective exposure apparatuses. For this purpose, an internal optical sensor is permanently provided in the exposure apparatus, and the illuminance on the image plane is indirectly measured, and the exposure amount between the respective exposure apparatuses is matched based on the measurement result. However, the internal light sensor provided for each exposure apparatus does not always detect an accurate illuminance, and an error may occur due to aging or the like, and it is necessary to calibrate the internal light sensor. is there.

There is also a need to centrally manage the relative illuminances in order to match the throughput of processing by each exposure apparatus.

Therefore, an inter-unit illuminometer for measuring the relative illuminance between the respective exposure apparatuses is used. This illuminometer
It is configured to be detachable from a dedicated mounting section (adapter section) provided near the wafer holder on the wafer stage, and the operator manually mounts (inserts) the illuminometer on the mounting section and inserts the image plane. Measure the above illuminance directly. The worker removes the illuminometer from the mounting part after the illuminance measurement ends,
By working in the same way for the other exposure equipment,
The illuminance of each exposure device is measured.

[0006]

By the way, since the projection optical system and other members exist near the wafer stage, the work of attaching and detaching the illuminometer must be performed by putting a hand in a very limited space. In addition, due to the configuration of the exposure apparatus,
Since there is a certain distance from the position of the operator to the position of the wafer stage, the work is not easy, and it takes a long time to attach and detach the work, and it comes in contact with precision members etc. on or near the wafer stage. There have been problems such as damage or damage caused by dropping dust.

In some cases, the illuminance measurement by the illuminometer is performed by interrupting the exposure process during a series of exposure processes. The opening and closing of the door and the like disturbs the temperature in the chamber, and it takes a long time until the temperature in the chamber is stabilized after the operation is completed, during which the exposure process cannot be restarted.

The present invention has been made in view of such circumstances, and has as its object to simplify the work involved in measuring the illuminance of illumination light on the image forming plane of a projection optical system of an exposure apparatus, and to reduce the time required for illuminance measurement. And

[0009]

In the following description, the present invention will be described with reference to the member codes shown in the drawings showing the embodiments. However, the present invention is not limited to the members shown in the drawings attached with.

According to a first aspect of the present invention, there is provided an illuminometer, wherein a pattern image from a mask (11) illuminated by an illumination optical system is transferred to a photosensitive substrate (14) held on a substrate stage (28). In an illuminometer (50) for measuring the illuminance of illumination light in the vicinity of the image forming plane of the projection optical system of an exposure apparatus configured to project the light onto the projection optical system (13), the exposure apparatus can convey the same as the photosensitive substrate. Dummy substrate (51) formed in a thin plate shape
And an illuminance detection unit (52) is provided integrally therewith.

The illuminometer according to the present invention is formed in a thin plate shape so that it can be transported in the same manner as the photosensitive substrate. The illuminance is measured in this state, and after the illuminance is measured, the illuminance can be carried out of the substrate stage.

Therefore, the work of attaching and detaching the illuminance meter to and from the substrate stage as in the related art is unnecessary, and the work involved in the illuminance measurement is extremely simplified. In addition, since there is no need to open and close the chamber door and the like in connection with the measurement of the illuminance, not only does it take a long time to resume the exposure processing due to the air conditioning in the chamber, etc. Since the measurement can be performed, the interruption time of the exposure processing accompanying the illuminance measurement can be reduced, and the illuminance can be measured extremely efficiently.

According to a second aspect of the present invention, in the illuminance measuring method, a dummy substrate (51) formed in a thin plate shape so as to be conveyable similarly to the photosensitive substrate (14) to be exposed is integrated. An illuminometer (50) provided with an illuminance detector (52) is provided between the plurality of exposure devices (30a, 30b, 30c, 30d) on the substrate stage (28) similarly to the photosensitive substrate. The projection optical system (1
3) The illuminance of the illumination light in the vicinity of the image plane is measured.

According to the illuminance measuring method according to the present invention, an illuminometer formed in a thin plate so as to be transportable like a photosensitive substrate is used, and the illuminometer is loaded and unloaded onto a substrate stage in the same manner as the photosensitive substrate. In addition, since the illuminance of each exposure apparatus is measured, the work of attaching and detaching the illuminometer to and from the substrate stage as in the related art is not required, and the work involved in the illuminance measurement is extremely simplified.

Further, since there is no necessity to open and close the doors of the chamber, etc. in connection with the measurement of the illuminance, not only does it take a long time to restart the exposure processing due to the air conditioning in the chamber, but also an extremely short time. Illuminance can be measured in each exposure apparatus in a lithography system (manufacturing line such as a semiconductor device) having a plurality of exposure apparatuses and the like. The processing interruption time can be shortened, and the illuminance of each exposure apparatus can be easily managed.

According to a third aspect of the present invention, in an exposure apparatus, an image of a pattern from a mask (11) illuminated by an illumination optical system is transferred to a substrate holder (28) mounted on a substrate stage (28). 151)
Optical system (13) on a photosensitive substrate (14) held by
The substrate holder is configured to be detachable from the substrate stage, and has an illuminance detector (52) integrally on a holding surface for the photosensitive substrate. I do.

The exposure apparatus according to the present invention is provided with a substrate holder which is detachably attached to the substrate stage and has an illuminance detecting section. Therefore, for example, the substrate holder is transported by the transport system (103). , Loaded on the substrate stage
Place, measure the illuminance in this state, after measuring the illuminance,
It is possible to carry it out of the substrate stage. Therefore,
The work of attaching and detaching the illuminance meter to and from the substrate stage as in the related art is unnecessary, and the work involved in the illuminance measurement is extremely simplified. In addition, since the need to open and close the chamber door and the like can be eliminated along with the measurement of the illuminance, not only does it take a long time to resume the exposure processing due to air conditioning in the chamber, but also an extremely short time. , The interruption time of the exposure processing can be shortened, and the illuminance can be measured efficiently.

According to a fourth aspect of the present invention, there is provided an illuminance measuring method, wherein the substrate holder is configured to be detachable from the substrate stage and has an integrated illuminance detection section. Are sequentially mounted on the substrate stages of a plurality of exposure apparatuses (30a, 30b, 30c, 30d), and the illuminance in the vicinity of the imaging plane of the projection optical system of each exposure apparatus is measured. I do.

According to the illuminance measuring method of the present invention, each exposure is performed while loading and unloading the substrate holder onto and from the substrate stage using a substrate holder which is detachably mounted on the substrate stage and has an illuminance detecting section. Since the illuminance of the apparatus is measured, the work of attaching and detaching the illuminometer to and from the substrate stage as in the related art is unnecessary, and the work involved in the illuminance measurement is extremely simplified.

Further, since there is no necessity to open and close the chamber door and the like in connection with the measurement of the illuminance, not only does it take a long time to resume the exposure processing due to the air conditioning in the chamber, but also very short time. Illuminance can be measured in each exposure apparatus in a lithography system (manufacturing line such as a semiconductor device) having a plurality of exposure apparatuses and the like. The processing interruption time can be shortened, and the illuminance of each exposure apparatus can be easily managed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. An embodiment Figure 1 is a block diagram showing an outline of the circuit configuration of the illuminance meter according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the characteristics of the main circuit in a luminometer shown in FIG. 1, FIG. 3 is a lithographic FIG. 4 is a schematic view showing an example of an exposure apparatus, FIG. 5 is a schematic perspective view of a wafer stage, FIG. 6 is a schematic view showing an example of a method of calibrating an illuminometer, and FIG. 7 is a wafer of the exposure apparatus. FIG. 8 is a cross-sectional plan view showing a configuration of a transfer system and the like of FIG.
FIG. 3 is a perspective view showing an external configuration of a wafer-type illuminometer in which an optical sensor is provided integrally with a dummy wafer.

(1) Lithography System A lithography system to which the present invention is applied is a system for manufacturing a semiconductor device as a micro device. As shown in FIG. 3, a KrF excimer laser is used as an illumination light source for exposure. An exposure apparatus 30a and exposure apparatuses 30b to 30d using an ArF excimer laser as an illumination light source for exposure are mixed. These two types of exposure apparatus 3
Reference numerals 0a to 30d are connected to the same host computer 76, and their operation status and the like are monitored and production management is performed. Each of these exposure apparatuses 30a to 30d
Is measured by the wafer-type illuminometer 50 as an inter-unit illuminometer, and is used for matching the exposure amount between the exposure apparatuses. In this embodiment, a system in which two types of exposure apparatuses having different light sources are mixed will be described. However, a system including a plurality of exposure apparatuses of a single type, or a system including a plurality of types of exposure apparatuses. System.

(2) Optical System of Exposure Apparatus First, the optical system of one exposure apparatus 30a will be mainly described with reference to FIG. Another exposure apparatus 30 shown in FIG.
Although the description of b to 30d is omitted, the basic configuration is the same as that shown in FIG. 4 except for the type of the light source for the exposure illumination light.

As shown in FIG. 4, the exposure apparatus 30a according to the present embodiment is a so-called step-and-scan type exposure apparatus, which projects a part of a pattern on a reticle 11 as a mask by using a projection optical system 13. The reticle 11 and the wafer 14 are exposed to the projection optical system 1 in a state where the wafer is coated with a resist as a substrate through a reduced projection exposure.
By performing synchronous movement with respect to 3, the reduced image of the pattern on the reticle 11 is sequentially transferred to each shot area of the wafer 14, and a semiconductor device is manufactured on the wafer 14.

The exposure apparatus 30a of this embodiment uses a KrF excimer laser (oscillation wavelength 248n) as the exposure light source 1.
m). The laser beam LB pulse-emitted from the exposure light source 1 enters the beam shaping / modulating optical system 2. In the present embodiment, the beam shaping / modulating optical system 2 includes a beam shaping optical system 2a and an energy modulator 2b. The beam shaping optical system 2a includes a cylinder lens, a beam expander, and the like, and the cross-sectional shape of the beam is shaped so as to efficiently enter the subsequent fly-eye lens 5.

The energy modulator 2b shown in FIG. 4 comprises an energy coarse adjuster, an energy fine adjuster and the like.
The energy rough adjuster has a plurality of ND filters having different transmittances (= (1−dimming rate) × 100 (%)) arranged on a rotatable revolver, and the revolver is rotated by rotating the revolver. The transmittance for the incident laser beam LB can be switched from 100% in a plurality of steps. Note that a revolver similar to the revolver may be arranged in two stages so that the transmittance can be more finely adjusted by a combination of two sets of ND filters. On the other hand, the energy fine adjuster continuously fine-tunes the transmittance for the laser beam LB within a predetermined range by a double grating method or a method combining two parallel flat glass plates with variable tilt angles. . However,
Instead of using this energy fine adjuster, the energy of the laser beam LB may be finely adjusted by the output modulation of the excimer laser light source 1.

In FIG. 4, the beam shaping / modulating optical system 2
The laser beam LB emitted from the lens enters the fly-eye lens 5 via a mirror M for bending the optical path.

The fly-eye lens 5 is connected to the subsequent reticle 1
A number of secondary light sources are formed to illuminate 1 with a uniform illumination distribution. As shown in FIG. 4, an aperture stop (so-called σ stop) 6 of an illumination system is arranged on an emission surface of the fly-eye lens 5, and a laser beam (hereinafter, referred to as a beam) emitted from a secondary light source in the aperture stop 6 is provided. , "Pulse illumination light IL")
Is a beam splitter 7 having a small reflectance and a large transmittance.
, And the pulse illumination light IL as the illumination light for exposure transmitted through the beam splitter 7 is incident on the condenser lens 10 via the relay lens 8.

The relay lens 8 includes a first relay lens 8A
, A second relay lens 8B, and these lenses 8A, 8B
It has a fixed illumination field stop (fixed reticle blind) 9A and a movable illumination field stop 9B interposed therebetween. The fixed illumination field stop 9A has a rectangular opening, and the pulsed illumination light IL transmitted through the beam splitter 7 passes through the rectangular opening of the fixed illumination field stop 9A via the first relay lens 8A. ing. The fixed illumination field stop 9A is arranged near a conjugate plane with respect to the pattern surface of the reticle. The movable illumination field stop 9B has an opening whose position and width in the scanning direction are variable.
A, and further limiting the illumination field via its movable illumination field stop 9B at the beginning and end of the scanning exposure to reduce unwanted portions (shots on the wafer where the reticle pattern is transferred). Out of area)
Exposure is prevented.

As shown in FIG. 4, the fixed illumination field stop 9A
Illumination light IL that has passed through the movable illumination field stop 9B
Is a reticle 1 held on a reticle stage 15 via a second relay lens 8B and a condenser lens 10.
1 is illuminated with a uniform illumination distribution on the rectangular illumination region 12R. The pattern in the illumination area 12R on the reticle 11 is projected through the projection optical system 13 through a projection magnification α (α is, for example, ４ ，,
An image reduced by ５) is applied to an illumination field field 12 on a photoresist-coated wafer (photosensitive substrate) 14.
W is projected and exposed. Hereinafter, the optical axis AX of the projection optical system 13
And the scanning direction of the reticle 11 with respect to the illumination area 12R in a plane perpendicular to the optical axis AX (ie,
The direction parallel to the plane of FIG. 4) will be described as the Y direction, and the non-scanning direction perpendicular to the scanning direction as the X direction.

At this time, the reticle stage 15 is scanned by the reticle stage driving section 18 in the Y direction. The Y coordinate of the reticle stage 15 measured by the external laser interferometer 16 is supplied to the stage controller 17,
The stage controller 17 controls the position and speed of the reticle stage 15 via the reticle stage driving unit 18 based on the supplied coordinates.

On the other hand, the wafer 14 is mounted on a wafer stage 28 via a wafer holder WH described later. The wafer stage 28 has a Z tilt stage 19 and an XY stage 20 on which the Z tilt stage 19 is mounted. The XY stage 20 moves the wafer 1 in the X direction and the Y direction.
4 and the wafer 14 is scanned in the Y direction. Further, the Z tilt stage 19 holds the Z
Direction position (focus position) and XY
It has a function of adjusting the inclination angle of the wafer 14 with respect to the plane. The X coordinate and the Y coordinate of the XY stage 20 (wafer 14) measured by the movable mirror fixed on the Z tilt stage 19 and the external laser interferometer 22 are supplied to the stage controller 17, and the stage controller 17
Is based on the supplied coordinates.
The position and the speed of the XY stage 20 are controlled via 3.

The operation of the stage controller 17 is controlled by a main control system (not shown) which controls the entire apparatus. At the time of scanning exposure, the reticle 1
1 is in the + Y direction (or −Y) via the reticle stage 15.
Synchronization to be scanned at a speed V _R in a direction), the wafer 14 via the XY stage 20 is illuminated field field 12
Speed α · V in the −Y direction (or + Y direction) with respect to W
_The scanning is performed at _R (α is a projection magnification from the reticle 11 to the wafer 14).

The wafer 1 on the Z tilt stage 19
An uneven illuminance sensor 21 composed of a light conversion element is permanently provided in the vicinity of 4, and the light receiving surface of the uneven illuminance sensor 21 is set at the same height as the surface of the wafer 14. As the uneven illuminance sensor 21, a PIN-type photodiode or the like having sensitivity in far ultraviolet and having a high response frequency for detecting pulsed illumination light can be used. A detection signal of the uneven illuminance sensor 21 is supplied to an exposure controller 26 via a peak hold circuit (not shown) and an analog / digital (A / D) converter.

The pulse illumination light IL reflected by the beam splitter 7 shown in FIG. 4 is received by an integrator sensor 25 composed of a light conversion element via a condenser lens 24, and the photoelectric conversion signal of the integrator sensor 25 is The output DS is supplied to the exposure controller 26 via a peak hold circuit (not shown) and an A / D converter. The correlation coefficient between the output DS of the integrator sensor 25 and the illuminance (exposure amount) of the pulse illumination light IL on the surface of the wafer 14 is obtained in advance using an illuminometer and stored in the exposure controller 26. The exposure controller 26 controls the light emission timing and light emission power of the exposure light source 1 by supplying the control information TS to the exposure light source 1.
The exposure controller 26 further includes an energy modulator 2b
The stage controller 17 controls the opening and closing operation of the movable illumination field stop 9B in synchronization with the operation information of the stage system.

(3) Wafer Transport System Next, the wafer transport system of this exposure apparatus will be described. This exposure apparatus includes an automatic wafer transfer device. As the automatic wafer transfer device, for example, a device as disclosed in JP-A-7-240366 can be employed. This automatic transporter will be described with reference to FIG.

The optical system 10 of the exposure apparatus as shown in FIG.
0 is stored in the air-conditioned first independent chamber 101.
is set up. A wafer holder WH is held on the wafer stage 28 (Z tilt stage 19) by vacuum suction, and the wafer 14 to be exposed is held on the wafer holder WH by vacuum suction.

A notch called an orientation flat (or notch) is formed in a part of the circular outer periphery of the wafer 14, and the notch is oriented in a predetermined direction, and the center of the wafer 14 is set in the wafer holder. The wafer 14 is loaded on the wafer holder WH so as to have a predetermined positional relationship with respect to WH. In the present embodiment, an automatic wafer transfer apparatus (transfer system) 103 for loading (unloading) the wafer onto the wafer holder WH and unloading (unloading) the wafer from the wafer holder WH includes a first independent chamber 101. Is installed in the second independent chamber 102 adjacent to the second independent chamber 102.

The guide portion of the automatic wafer transfer device 103 is
A scalar type robot hand 106 is composed of a horizontal slider main body 104 extending in the X direction and a vertical slider main body 105 extending in the Y direction. Scalar robot hand 106
Is an articulated robot provided with a hand unit 107 having a suction unit for vacuum-sucking the wafer 14, and is moved in the X direction along the horizontal slider main body 104, and freely moves the hand unit 107 in the θ and R directions. You can move.

In the vicinity of the horizontal slider body 104, storage shelves 108 and 109 for storing the wafers 14 are fixed. Further, temporary placing tables 110 and 111 for temporarily placing the wafer 14 thereon are provided. Temporary table 11
A plurality of (four) pins for mounting a wafer are mounted on 0 and 111. Independent chambers 10 near storage shelves 108 and 109 and temporary storage tables 110 and 111
2, storage shelves 108 and 109 are provided from outside.
Openings 112 and 113 for exchanging the components are provided. A door frame unit having an open / close door (not shown) is installed in these openings 112 and 113.

The hand portion 107 of the scalar type robot hand 106 is protruded from the opening 114 on the left side of the independent chamber 102 to transfer the wafer 14 to an external device (such as an external photoresist coater or a developing device). And the wafer 14 can be moved to another position Q1.
Can be delivered. Further, by moving the scalar type robot hand 106 to the position Q7 and protruding the hand unit 107 from the opening 115 on the right side of the independent chamber 102, the wafer 14 can be transferred to and from an external device. However, the transfer of the wafer 14 can be performed. Similarly, by moving the scalar type robot hand 106 to the position Q3, Q5 or Q6, it is possible to transfer the wafers 14 to the respective storage shelves 108, the temporary storage table 110 or the temporary storage table 111.

The vertical slider body 105 protrudes into the independent chamber 101 through an opening on the side surface of the independent chamber 101 and an opening on the side surface of the independent chamber 102, and is slidable in the longitudinal direction on the side surface of the vertical slider body 105. Two sliders (transfer arms) 116 and 117 having a U-shaped contact portion of the wafer 14 are attached.
These two sliders 116 and 117 move independently between the inside of the independent chamber 101 and the inside of the independent chamber 102 while holding the wafer 14 by the respective vacuum suction parts. Then, the scalar robot hand 106
For example, after removing the wafer 14 from the storage shelf 108, the turntable 1
The wafer 14 is transferred to the slider 116 or 117 via 18. Thereafter, the scalar robot hand 106 that has received the exposed wafer 14 from the slider 116 or 117 via the vertical movement of the turntable 118 similarly returns the wafer 14 to, for example, a storage shelf 108.

Also, the portion of the scalar robot hand 106 that comes into contact with the wafer 14, such as the hand portion 107, the slider 116, and the slider 117, is formed of a conductive ceramic having a dense surface. However, a dense conductive ceramic may be applied to the surface of the contact portion with the wafer 14 by coating or the like.

Horizontal slider body 104 and vertical slider body 1
In the vicinity of the area where the line 05 intersects, that is, in the vicinity of the position Q4,
The pre-alignment apparatus 11 having a sensor for detecting the center position and posture of the turntable 118 and the wafer 14 and the like.
9 and so on.

The scalar type robot hand 106 places the wafer 14 on the turntable 118 so that the center position of the wafer 14 coincides with the rotation center of the turntable 118.
Is placed. At this time, the slider 11
6 is moved. The wafer 14 is vacuum-sucked on the turntable 118.

In this state, the turntable 118 is rotated, and the notch of the wafer 14 is detected by a sensor. According to the detection result, the notch of the wafer 14 is located at a position facing the horizontal slider body 104, for example. Turntable 1
Stop rotation of 18. Then turntable 11
8, the suction of the wafer 14 is released, and the turntable 1
18 descends to vacuum-suck the wafer 14 on the upper surface of the slider 116. Next, the slider 116 is moved to the independent chamber 101 side along the vertical slider main body 105,
The slider 116 is moved by a wafer vertical movement mechanism (transfer means) composed of a plurality of vertically movable pins and the like described later.
The wafer 14 onto the wafer holder WH. At this time, the center of the wafer 14 and the position of the notch are exactly in a predetermined state, and the wafer 14 is placed on the wafer holder WH.

Next, the essential parts of the wafer stage and the wafer holder will be described in more detail with reference to FIGS. Wafer holder WH is held by suction on wafer stage 28 (Z tilt stage 19). The wafer stage 28 has a round hole 122 into which the bottom small diameter portion 121 of the wafer holder WH can be fitted.
A circular guide hole 123 is formed in the center of the inner bottom surface in the vertical direction. Inside the guide hole 123, a holder supporting member 1 that can move up and down along the guide hole 123 is provided.
24, and the holder support member 124 is
It is moved up and down by a drive mechanism (not shown). That is, the guide hole 123, the holder support member 124, and a driving mechanism (not shown) constitute a holder attaching / detaching mechanism.

The upper end of the holder support member 124 has a substantially U-shaped section.
A notch 125 having a character shape is formed, so that the tip of a holder transfer arm of a holder automatic transfer device described later can be inserted through the cutout 125 when the wafer holder WH is replaced. In addition, round holes 12
On the inner bottom surface of the wafer 2, three vertically moving pins 126 constituting a wafer vertically moving mechanism for supporting the wafer at three points when the wafer is replaced and for vertically moving the wafer are provided in the vertical direction. When the wafer holder WH is suction-fixed to the wafer stage 28, each of the vertically moving pins 126 is connected to the wafer holder WH via a circular hole (not shown) provided corresponding to the vertically moving pin 126. It moves up and down in the penetrating state. Note that there are generally concentric convex portions 127 on the wafer holder WH, and the wafer 14 is mounted on these concentric convex portions.

(4) Wafer Holder Transfer System Although the illustration of the exposure apparatus in this embodiment is omitted,
In addition to the above-described automatic transfer device for the wafer 14, a transfer device for automatically transferring the wafer holder WH is provided. As the holder automatic transfer device, for example, JP-A-8-250409
Japanese Unexamined Patent Publication (Kokai) No. H10-260, can be adopted.

The holder automatic transfer device includes an articulated robot and a transfer arm having a hand unit for suction-holding the wafer holder WH, and detaches and transfers the wafer holder WH held on the wafer table 28 for wafer holder WH. This is a device that removes a clean wafer holder WH from a storage shelf for a wafer holder, transports the wafer holder WH to a position near the wafer stage 28, and suction-holds the wafer holder 28 on the wafer stage 28. The configuration and the like are almost the same as those of the above-described automatic transfer device for the wafer 14, and therefore the detailed description thereof will be omitted.

(5) Wafer-type illuminometer In this embodiment, a step-and-scan projection exposure apparatus 30a using the above-described KrF excimer laser as exposure illumination light, and an ArF excimer laser for exposure illumination In a method of manufacturing a semiconductor device using a lithography system in which step-and-scan type projection exposure apparatuses 30b to 30d using light are mixed, the illuminance of each of the exposure apparatuses 30a to 30d is detected, and To match the exposure amount, a wafer type illuminometer 50 is used as an inter-unit illuminometer whose circuit configuration is shown in FIG. 1 and whose external configuration is shown in FIG.

The illuminometer 50 has an optical sensor (illuminance detecting section) 52 and an illuminometer circuit section 54. Optical sensor 5
2, a dummy wafer 5 formed in substantially the same shape as a wafer (photosensitive substrate) 14 to be exposed, as shown in FIG.
1 is provided at a substantially central portion. Here, the outer shape of the dummy wafer 51 is shown as a circular plate,
It is not limited to such a shape. For example, in an exposure apparatus for manufacturing a liquid crystal display element, the exposure apparatus is formed in substantially the same shape as a glass substrate to be exposed, that is, in a rectangular plate shape. There may be.

The light sensor 52 has a built-in light conversion element, and outputs an electric signal according to the incident energy of the illumination light for exposure applied to the light sensor 52. The light conversion element that can be used in the present embodiment is not particularly limited, and a light conversion element using a photovoltaic effect, a Schottky effect, a photoelectromagnetic effect, a photoconductive effect, a photoelectron emission effect, a pyroelectric effect, or the like. However, in the present embodiment, a broadband optical sensor element capable of detecting a plurality of exposure illumination lights each having an oscillation spectrum in a predetermined wavelength band is preferable. This is for detecting light of both KrF and ArF wavelengths. From such a viewpoint, a pyroelectric sensor element that is a light conversion element utilizing the pyroelectric effect is preferable.

Although the illuminometer circuit section 54 is not particularly limited, in this embodiment, it is provided integrally with the dummy wafer 51 like the optical sensor 52. Illuminance meter circuit 54
Has an amplifier circuit (amplifier) 56 to which an output signal (illuminance signal) from the optical sensor 52 is input via a wiring (pattern) 53, as shown in FIG. The amplification circuit 56 is connected to the amplification factor storage device 64, and amplifies the illuminance signal from the optical sensor 52 at the amplification factor stored in the amplification factor storage device 64.

The amplification factor storage device 64 stores an amplification factor set in advance according to the type of the illumination light for exposure. In this embodiment, the amplification factor for KrF for the illumination light for KrF exposure and the amplification factor for KrF are stored. , And the amplification factor for ArF for the illumination light for ArF exposure. How to set these amplification factors will be described later.

The amplifier circuit 56 has a peak hold (P /
H) A circuit 58 is connected to hold the peak value of the illuminance signal amplified by the amplifier circuit 56. This peak hold circuit 58 is connected to an analog / digital conversion (A / D) circuit 60, and the peak value (analog signal) of the illuminance signal held by the peak hold circuit 58 is converted into a digital signal.

The analog / digital conversion circuit 60 is connected to the calibration circuit 62, and the digital signal (illuminance signal) converted by the analog / digital conversion circuit 60 is calibrated by the calibration circuit 62. The calibration by the calibration circuit 62 is performed by the calibration value storage device 6 connected to the calibration circuit 62.
6 is performed based on the calibration value stored. The calibration value storage device 66 stores a calibration value preset according to the type of the illumination light for exposure. In the present embodiment, a calibration value for KrF for illumination light for KrF exposure and an ArF exposure And an ArF calibration value for the illumination light. How to set these calibration values will be described later.

The reason why the calibration by the calibration circuit 62 is necessary will be described below. That is, the digital signal before being input to the calibration circuit 62 is a digital signal of an amount corresponding to the illuminance of the light incident on the optical sensor 52, but in order to calculate the illuminance from the digital signal, an amplification circuit This is because it is necessary to perform the correction in consideration of the amplification factor at 56 and the wavelength dependency of the sensor element used in the optical sensor 52. Without such calibration, accurate illuminance cannot be calculated and displayed. In the present embodiment, since the optical sensor 52 is irradiated with two types of exposure illumination light, KrF and ArF, the calibration value performed by the calibration circuit 62 is KrF
Two kinds of calibration values are required: a KrF calibration value for the exposure illumination light and an ArF calibration value for the ArF exposure illumination light.

The output terminal of the calibration circuit 62 is connected to a storage device 74 for storing and holding the result data, and the data calibrated by the calibration circuit 62 and converted into illuminance (incident energy) is output to the result data. The data is stored in the storage device 74. The result data (data calibrated by the calibration circuit 62 and converted into illuminance) stored and held in the result data storage device 74 is provided to the input / output terminal 72 by using a data reading device (not shown), a host computer 76, or the like. It can be read out by connecting accordingly. The illuminometer circuit unit 54 may be provided with a wireless communication device so that the result data is read out by wireless communication.

Further, in this example, the optical sensor 52 and the illuminance meter circuit section 54 are integrally provided on the dummy wafer 51. However, only the optical sensor 52 is provided on the dummy wafer 51, and the illuminance meter circuit section 54 is connected to the dummy wafer. 51 and a flexible connecting cable 5 between them.
3 may be used. In addition, the dummy wafer 5
1, an optical sensor 52 and a wireless communication device are provided, an illuminometer circuit unit 54 is formed independently of the dummy wafer 51, and a detection value of the optical sensor 52 is transmitted by wireless communication to the illuminometer circuit unit 54.
May be transferred to Note that, in these cases, the result data stored in the result data storage unit 74 may be displayed on a display device.

The illuminometer 50 can be constituted by using the real wafer 14 as the dummy wafer 51 and forming the optical sensor 52 and the illuminometer circuit section 54 directly on the wafer by lithography. A printed wiring board or a thin plate member having a printed wiring board (for example, a ceramic board) as the dummy wafer 51
And forming the optical sensor 52 and the illuminometer circuit portion 54 on the printed wiring board.

Amplification rate storage device 64 and calibration value storage device 6
A switching circuit 68 is connected to 6 as required. The switching circuit 68 switches between the amplification factor used in the amplification circuit 56 and the calibration value used in the calibration circuit 62 according to the type of the illumination light for exposure input to the optical sensor 52. 66 and / or outputs a switching signal to the amplification circuit 56 and the calibration circuit 62.

The switching signal from switching circuit 68 may be generated based on a selection signal manually input from input device 70, or may be generated based on a selection signal input from input / output terminal 72. Alternatively, remote control may be performed by a wireless communication device. The input device 70 is not particularly limited, but may be a dip switch or the like. The operator operates such an input device 70
, The type of exposure light (KrF or ArF in the present embodiment) whose illuminance is to be measured is manually selected. By using the input device 70 to select the type of exposure illumination light (in this embodiment, KrF or ArF),
A switching signal is output from the switching circuit 68, and the amplification factor used in the amplification circuit 56 and the calibration value used in the calibration circuit 62 are determined.
It is read from each of the storage devices 64 and 66.

The input / output terminal 72 shown in FIG.
Exposure devices 30a to 30d where optical sensor 52 is to be installed
3 and the host computer 76 shown in FIG. 3 can be connected. By connecting to such devices, the exposure devices used in the exposure devices 30a to 30d to measure the illuminance can be obtained from these devices. It is also possible to input a selection signal indicating the type of illumination light (KrF or ArF in the present embodiment).

Next, a method for setting an amplification factor to be stored in the amplification factor storage device 64 and a calibration value to be stored in the calibration value storage device 66 shown in FIG. 1 will be described. In an ArF excimer laser exposure apparatus, a resist used is generally higher in sensitivity than a resist used in a KrF excimer laser exposure apparatus. In an ArF excimer laser having less energy stability than a KrF excimer laser,
In order to improve the accuracy of the integrated exposure amount control, the number of integrated pulses is increased. Therefore, the energy per pulse is smaller than that of the KrF excimer laser exposure apparatus. Typically, there is a difference of several times to about 10 times in the incident energy level of the illuminometer.

Therefore, conventionally, even if it is attempted to measure the illuminance of an ArF excimer laser exposure apparatus using an illuminometer optimized by a KrF excimer laser exposure apparatus, the output signal of the sensor is reduced, and sufficient linearity is obtained. There is a high possibility that a wide measurement range cannot be obtained.

If the wavelength used is different, the sensitivity of the sensor slightly changes. Therefore, it is difficult to accurately measure the absolute value of the illuminance with the same calibration value as that of the KrF excimer laser.

Therefore, in this embodiment, two types of amplification factors, KrF amplification factor and ArF amplification factor, are stored in the amplification factor storage device 64 shown in FIG. doing. The calibration value storage device 66 stores K
Two kinds of amplification factors, i.e., a calibration value for rF and a calibration value for ArF, are stored, and are used by switching according to the exposure wavelength.

First, K to be stored in the amplification factor storage device 64
The setting of the amplification factor for rF and the amplification factor for ArF will be described. As shown in FIG. 2, in the peak hold circuit 58,
In the relationship between the input signal (input voltage) and the output signal (output voltage), the input voltage V0 is larger than V1 and V
If it is smaller than 2, there is a region having a good linear relationship (proportional relationship). In other words, illuminometer 50
Is dependent on the followability of the peak hold circuit 58. Therefore, in order to calculate an accurate illuminance, the output voltage V0 (input voltage to the peak hold circuit 58) of the amplifier circuit 56 is V1 <V0 <V2.
It is necessary to set the amplification factor so that

At this time, since the irradiation energy per pulse in the case of KrF is different from the irradiation energy per pulse in the case of ArF, the KrF is set so that the output voltage is about V0 for each. The amplification factor for use gKrF and the amplification factor for ArF gArF are determined. These KrF amplification factors gKrF and ArF amplification factors gArF are stored in the amplification factor storage device 64 shown in FIG. The operation for storing may be performed by manually operating the input device 70 shown in FIG. 1, or may be stored by transmitting data from the input / output terminal 72.

The irradiation energy per pulse in the case of KrF and the irradiation energy per pulse in the case of ArF may be obtained by simulation using a computer analysis program or by actual measurement.

Next, the setting of the KrF calibration value and the ArF calibration value to be stored in the calibration value storage device 66 shown in FIG. 1 will be described. As a method for obtaining these calibration values, for example, as shown in FIG. 6, first, using a KrF laser device 78, light emitted from the same laser device 78 is simultaneously reflected and transmitted. Illuminates the optical sensor 52a of the KrF reference illuminometer 50a and the optical sensor 52 of the illuminometer 50 to be calibrated via the known beam splitter 80. At that time, the amplification factor used in the amplification circuit 56 of the illuminometer 50 to be calibrated is set using the switching circuit 68 so as to be the KrF amplification factor. Next, the value detected by the illuminometer 50 to be calibrated is the KrF reference illuminometer 50a.
The KrF calibration value is also determined by using the reflectance and the transmittance of the beam splitter 80 so that the KrF calibration value becomes the same value as the detection value obtained by the above-described method, and the determined KrF calibration value is shown in FIG. The stored calibration value is stored in the calibration value storage device 66 shown in FIG. KrF
The determination and storage of the calibration value for calibration may be performed manually, but the reference illuminometer 50a and the illuminometer 50 to be calibrated are connected directly or indirectly via another device, and are automatically performed. May be.

In determining and storing the calibration value for ArF, the laser device 78 shown in FIG. 6 is used for ArF, the reference illuminometer 50a is also replaced with the one for ArF, and the illuminometer 50 to be calibrated is further replaced. The amplification factor used in the amplification circuit 56 of
The same operation as described above may be performed by setting using the switching circuit 68 so that the amplification factor for ArF is obtained.

(6) Illuminance Measurement Method In the present embodiment, when measuring the illuminance, the wafer storage shelf 10 of the exposure apparatus in which the illuminance of the dummy wafer 51 is to be measured.
8 or 109 or the temporary placing tables 110 and 111 are accommodated or placed in the same manner as the wafer 14, and are transferred by the automatic wafer transfer device (transfer system) 103 in the same manner as the normal wafer 14 and placed on the wafer holder WH. Vacuum adsorb. Next, the drive of the wafer stage 28 is controlled in the X and Y directions, and FIG.
The illumination light for exposure that has passed through the projection optical system 13 shown in FIG. 4 is made incident on the light conversion element of the optical sensor 52 on the dummy wafer 51, and the illuminance of the illumination light on the image forming plane of the projection optical system 13 (or in the vicinity) is measured I do.

The light receiving surface of the optical sensor 52 provided integrally with the dummy wafer 51 is provided immediately below the aperture plate, and is provided at the lower surface of the aperture plate, that is, the light receiving surface of the optical sensor 52 during illuminance measurement. The surface is the projection optical system 13
The position of the dummy wafer 51 is adjusted by the Z tilt stage 19 so as to substantially coincide with the image forming plane.

When the measurement of the illuminance is completed, the automatic wafer transfer apparatus 103 moves the dummy wafer 51 to the wafer holder W.
H, and transported in the same manner as a normal wafer 14,
Return to the wafer storage shelves 108 and 109 or temporarily place the table 11
0,111. Next, the operator takes out the dummy wafer 51 from the chamber 102, connects to the host computer 76 or the like, and reads out the result data stored and held in the result data storage device 74. The reading of the result data may be performed when the illuminance measurement of one exposure apparatus is completed, or may be performed after the illuminance measurement of a plurality of exposure apparatuses is completed. Alternatively, the dummy wafer 51 may be automatically transferred between the front and rear exposure apparatuses, and the illuminance measurement of a plurality of exposure apparatuses may be performed automatically.

In this embodiment, a single illuminometer 50 is used.
And an amplification factor used in the amplification circuit 56 and a calibration circuit 62 in accordance with the light source employed by the exposure apparatus to be measured for illuminance.
Since the illuminance is measured by switching the calibration value used in the above for KrF and for ArF, the illuminance of both the KrF exposure apparatus and the ArF exposure apparatus is measured using a single illuminometer 50. be able to.

The illuminance output signal measured using the illuminometer 50 is transmitted to the integrator sensor 2 mounted on the exposure apparatus.
5 and used to calibrate an optical sensor such as the uneven illuminance sensor 21 or to match the exposure amount among the exposure devices 30a to 30d.

Next, another embodiment of the present invention will be described. FIG.
FIG. 3 is an external perspective view of a holder-type illuminometer in which an optical sensor is provided integrally with a dummy holder or a wafer holder in which an optical sensor is integrally provided. Components that are substantially the same as those in the above-described embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted.

That is, the holder type illuminometer 15 of this embodiment
0 is the same as that shown in FIG. 10 except that the optical sensor 52 is provided at a substantially central portion of a dummy holder (regardless of the function as a wafer holder) 151 formed in substantially the same shape as the wafer holder WH, as shown in FIG. It is almost the same as the wafer type illuminometer 50 of one embodiment. The dummy holder 151 has the same outer shape as the wafer holder WH shown in FIG.

In this embodiment, when measuring the illuminance, the dummy holder 151 is housed or placed in a holder storage shelf or a temporary mounting table of the exposure apparatus to be measured for the illuminance in the same manner as the wafer holder WH. The wafer is transferred by an automatic transfer device (substantially the same configuration as the automatic transfer device 103 for wafers) in the same manner as a normal wafer holder WH, and is held on the wafer stage 28 by vacuum suction. Next, the wafer stage 28 is driven and controlled in the X and Y directions, and the exposure illumination light having passed through the projection optical system 13 shown in FIG. The illuminance of the imaging plane of the system 13 (or its vicinity) is measured.

The light receiving surface of the optical sensor 52 provided integrally with the dummy holder 151 is provided immediately below the aperture plate, and is provided at the lower surface of the aperture plate during illuminance measurement, that is, the light receiving surface of the optical sensor 52. Surface is projection optical system 1
The position of the dummy holder 151 is adjusted by the Z tilt stage 19 so as to substantially coincide with the image plane No. 3.

When the measurement of the illuminance is completed, the holder automatic transfer device receives the dummy holder 151 from the wafer stage 28, transfers it in the same manner as a normal wafer holder WH, returns it to the holder storage shelf, or places it on the temporary table. Place. Next, the dummy holder 151 is taken out of the chamber 102, connected to the host computer 76 or the like, and the result data stored and held in the result data storage device 74 is read. The reading of the result data may be performed when the illuminance measurement of one exposure apparatus is completed, or may be performed after the illuminance measurement of a plurality of exposure apparatuses is completed. Alternatively, the dummy holder 151 may be automatically transferred between the front and rear exposure apparatuses, and the illuminance measurement of a plurality of exposure apparatuses may be performed automatically.

In this embodiment, the wafer holder W
Illuminance measurement is performed using a holder-type illuminometer in which an optical sensor 52 is integrally provided on a dummy holder (having or not having a function as a wafer holder) formed in substantially the same shape as H. , Such a dummy holder 15
Instead of 1, the illuminance of each of the exposure apparatuses 30a to 30d may be measured by a wafer holder (a wafer holder with an optical sensor) 153 in which the optical sensor 52 is integrally added to the wafer holder WH itself. When illuminance measurement is not performed, it can be used as a normal wafer holder, which is more efficient.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore,
Each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in the above-described embodiment, the wafer-type illuminometer 50, the holder-type illuminometer 150, or the substrate holder with an optical sensor capable of switching between two types, KrF and ArF, and measuring the illuminance will be described. However, the present invention is not limited to this, and may be of course a type that cannot be switched. Further, the combination of the two types of wavelengths is not limited to the above, and can be used for other combinations of wavelengths. further,
The combination of different wavelengths is not limited to two, but may be three or more. Furthermore, even if the wavelength is the same, it is also possible to switch between the incident energy ranges in order to detect the illuminance of the exposure illumination light having a different incident energy range with high accuracy.

Each circuit or device constituting the illuminometer circuit section 54 shown in FIG. 1 may be constituted only by an electric circuit (hardware) for realizing its function, but a part or all thereof May be realized by a microcomputer and a software program.

Further, in the above-described embodiment, the step-and-scan type reduced projection type scanning exposure apparatus (scanning stepper) has been described. For example, the reticle pattern is formed while the reticle 11 and the wafer 14 are stationary. Irradiating the entire surface with illumination light for exposure to collectively expose one defined area (shot area) on the wafer 14 to which the reticle pattern is to be transferred;
The present invention can be similarly applied to a reduction projection type exposure apparatus (stepper) of an up-repeat type, and further to an exposure apparatus of a mirror projection type or a proximity type.

Although all the optical elements of the projection optical system 13 shown in FIG. 4 are refraction elements (lenses), they may be optical systems consisting only of reflection elements (mirrors and the like). Alternatively, a catadioptric optical system including a refraction element and a reflection element (concave mirror, mirror, etc.) may be used. Further, the projection optical system 13 is not limited to the reduction optical system, but may be an equal-magnification optical system or an enlargement optical system.

Further, the present invention provides an EUV (Extreme U) having an oscillation spectrum in a soft X-ray region as a light source.
The present invention is also applicable to a reduced projection scanning exposure apparatus using a SOR that generates an intra violet, a laser plasma light source, or the like, or a proximity type X-ray scanning exposure apparatus.

[0091]

As described above, according to the present invention, according to the present invention, the exposure apparatus is provided with an illuminometer for measuring the illuminance of the illumination light (or a substrate holder having a part or all of the functions of the illuminometer). The transfer system (or the transfer system of the substrate holder) allows loading and unloading onto and from the substrate stage, eliminating the need to mount an illuminometer or the like on the substrate stage, greatly simplifying illuminance measurement. In addition to this, it is possible to prevent a precision member or the like existing on or near the substrate stage from being damaged, and to prevent the occurrence of obstacles such as dropping of dust. Further, the illuminance can be measured efficiently in a short time.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating a circuit configuration of an illuminometer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing characteristics of main circuits in the illuminometer shown in FIG.

FIG. 3 is a schematic diagram illustrating a configuration of a lithography system according to an embodiment of the present invention.

FIG. 4 is a schematic view illustrating an example of an exposure apparatus according to an embodiment of the present invention.

FIG. 5 is a schematic perspective view of a wafer stage of the exposure apparatus according to the embodiment of the present invention.

FIG. 6 is a schematic diagram illustrating an example of a method for calibrating an illuminometer according to an embodiment of the present invention.

FIG. 7 is a plan cross-sectional view illustrating a main part of the exposure apparatus according to the embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a main part of a wafer stage and a wafer holder of the exposure apparatus according to the embodiment of the present invention.

FIG. 9 is an external perspective view of an illuminometer according to an embodiment of the present invention.

FIG. 10 is an external perspective view of an illuminometer or a substrate holder according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exposure light source 11 ... Reticle (mask) 13 ... Projection optical system 14 ... Wafer (photosensitive substrate) 17 ... Stage controller 19 ... Z tilt stage 28 ... Wafer stage 30a-30d ... Exposure apparatus 50 ... Wafer illuminometer 51 ... Dummy wafer 52 Optical sensor 54 Illuminance meter circuit 56 Amplifying circuit 58 Peak hold circuit 60 Analog-to-digital conversion circuit 62 Calibration circuit 64 Amplification factor storage device 66 Calibration value storage device 68 Switching circuit 70 Input Device 72 Input / output terminal 74 Result data storage device 101, 102 Independent chamber 103 Automatic wafer transfer device (holder automatic transfer device) 106 Scalar robot hand 108, 109 Storage shelf 150 Holder illuminometer 151 Dummy holder 153 ... Wafer with optical sensor Holder

Claims (4)

[Claims] 1. An image forming apparatus, wherein an image of a pattern from a mask illuminated by an illumination optical system is projected onto a photosensitive substrate held on a substrate stage by a projection optical system. An illuminometer for measuring illuminance of illumination light in the vicinity of a surface, wherein an illuminance detection unit is provided integrally with a dummy substrate formed in a thin plate so as to be conveyable similarly to the photosensitive substrate. Total. 2. An illuminometer having an illuminance detector integrally provided on a dummy substrate formed in a thin plate so as to be able to be conveyed in the same manner as a photosensitive substrate to be exposed, and the illuminometer is used between a plurality of exposure apparatuses. Illuminance measurement, wherein the illuminometer is sequentially loaded and unloaded onto the substrate stage in the same manner as the photosensitive substrate, and the illuminance of the illumination light is measured in the vicinity of the imaging plane of the projection optical system of each exposure apparatus. Method. 3. An exposure apparatus configured to project an image of a pattern from a mask illuminated by an illumination optical system onto a photosensitive substrate held by a substrate holder mounted on a substrate stage by a projection optical system. An exposure apparatus, wherein the substrate holder is configured to be detachable from the substrate stage, and has an illuminance detection unit integrally on a holding surface for the photosensitive substrate. 4. A projection optical system for each exposure apparatus, while sequentially mounting a substrate holder detachably mounted on the substrate stage and integrally having an illuminance detector on the substrate stages of the plurality of exposure apparatuses. An illuminance measurement method, wherein the illuminance in the vicinity of an imaging plane of a system is measured.