JP2008270441A - Exposure apparatus and device manufacturing method - Google Patents

Abstract

An exposure apparatus is provided that has an exemplary purpose of reducing the number of calibrations of measuring means.
[Solution]
A first measuring means for measuring light through the projection optical system and a reference plane disposed on the substrate stage in order to measure the position of the image plane of the projection optical system in the direction of the optical axis of the projection optical system; Second measuring means for measuring the position of the target surface arranged on the stage in the direction of the optical axis, and based on the measured position of the image plane and the position of the reference plane as the measured target plane The second measuring unit is calibrated, the second measuring unit measures the position of the surface of the substrate as the target surface arranged on the substrate stage, and positions the substrate stage based on the measured surface position. Based on the output after calibration of the first measuring means in a state where the reference plane is positioned by the substrate stage and the output after calibration of the second measuring means with the reference plane in the state as the target plane, The output of the measuring means and the output of the second measuring means Calculating the relative change amount after calibration between.
[Selection] Figure 1

Description

  The present invention relates to an exposure apparatus and a device manufacturing method using the same.

In the exposure processing by the exposure apparatus, deviations such as a focal position and a plane direction position accompanying a change with time of the apparatus are periodically measured and the deviation is corrected.
The measurement process is stopped by production as a maintenance operation of the exposure apparatus and is performed by a maintenance worker, or the measurement process is periodically performed as a process condition during the exposure process.
Japanese Patent Laid-Open No. 8-8165 (Patent Document 1) proposes an exposure apparatus used for manufacturing a semiconductor device such as a semiconductor integrated circuit element and a method for manufacturing a semiconductor device using the exposure apparatus.
This is a proposal of an exposure apparatus that can easily correct the reduction ratio and improve the overlay accuracy, and a method of manufacturing a semiconductor device using the exposure apparatus.
JP-A-8-8165

Recent correspondence to miniaturized devices requires correction of changes over time of the apparatus with high accuracy.
On the other hand, in order to improve productivity, the time allowed for measurement processing other than exposure processing is shortened.
Accordingly, an object of the present invention is to reduce the number of calibrations of the measuring means.

An exposure apparatus of the present invention for solving the above problems includes a substrate stage that holds and moves a substrate, a projection optical system that projects light from an original onto a substrate held on the substrate stage, and the projection optical system First measuring means for measuring light through the projection optical system and a reference plane disposed on the substrate stage in order to measure the position of the image plane of the projection optical system in the direction of the optical axis of A second measuring means for measuring a position of the target surface arranged on the substrate stage in the direction of the optical axis,
Calibration of the second measuring unit based on the position of the image plane measured using the first measuring unit and the position of the reference plane as the target plane measured by the second measuring unit And measuring the position of the surface of the substrate as the target surface arranged on the substrate stage by the calibrated second measuring means, and based on the measured position of the surface, the substrate stage An exposure apparatus that exposes the substrate held on the positioned substrate stage through the original plate, wherein the first measuring means is in a state in which the reference surface is positioned by the substrate stage. Output of the first measurement means and the second measurement based on the output after the calibration of the second measurement means using the reference surface in the state as the target surface. The calibration between the output of the means It characterized by having a calculating means for calculating a relative change amount.

Furthermore, the exposure apparatus of the present invention includes a substrate stage that holds and moves the substrate,
A projection optical system that projects light from an original onto a substrate held on the substrate stage; first measurement means that measures a position of a reference mark disposed on the substrate stage via the projection optical system; Second reference means for measuring the position of the target mark placed on the substrate stage without using a projection optical system, and the position of the reference mark measured using the first measurement means And the position of the reference mark as the target mark measured using the second measuring means, the second measuring means is calibrated, and the second measuring means subjected to the calibration performs the calibration. The position of the alignment mark as the target mark arranged on the substrate held on the substrate stage is measured, the substrate stage is positioned based on the measured position of the alignment mark, and the positioning is performed. An exposure apparatus that exposes the substrate held on the substrate stage through the original plate, the output after calibration of the first measuring means in a state where the reference mark is positioned by the substrate stage; And between the output of the first measuring means and the output of the second measuring means based on the post-calibration output of the second measuring means using the reference mark in the state as the target mark. It has a calculation means for calculating the relative change after the calibration.

  According to the exposure apparatus of the present invention, the number of calibrations of the measuring means can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

Here, the schematic configuration of the exposure apparatus according to the first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a block diagram showing a schematic configuration of an exposure apparatus according to Embodiment 1 of the present invention.
The light source 1 is a light source for exposure. When the circuit pattern on the reticle 2 is transferred and exposed onto the wafer 8 as a substrate, an instruction from the exposure apparatus control system 70 is transmitted to the light source control system 30, and the operation of the light source 1 is controlled by the instruction from the light source control system 30. Is done.
Although not shown, an illumination optical system for changing the shape of illumination light and the like is configured between the exposure light source 1 and the reticle stage 4.
The illumination optical system is purged with a gas such as N ₂ for the purpose of stabilizing the imaging performance. Although not shown, the gas flow rate is measured by a flow meter for monitoring the flow rate formed in the vicinity of the gas outlet or outlet.
In the illumination optical system, a barometer for monitoring the atmospheric pressure value and a temperature / humidity meter for monitoring the atmospheric temperature and humidity in the illumination optical system are also configured.
Further, a thermohygrometer is configured to monitor the atmospheric temperature and humidity in the illumination optical system and between the illumination optical system and the reticle stage 4.

The reticle 2 is held on the reticle stage 4. The reticle reference plate 3 is held by the reticle stage 4 in FIG. 1, but may be optically fixed at a position equivalent to the reticle 2 in some cases.
In the scanning exposure apparatus, the reticle stage 4 is movable in the optical axis direction (z) of the projection optical system 5 and in the directions (x, y) perpendicular to this direction, and is rotated with respect to the optical axis and in the scanning direction. Pitching and yawing can be varied.
The wafer stage 10 is a substrate stage that holds and moves the wafer 8 that is a substrate.
The projection optical system 5 is an optical system that projects light from the reticle 2 as an original onto a wafer 8 that is a substrate held by a wafer stage 10 that is a substrate stage.
The reticle stage 4 is driven and controlled by an instruction from the exposure apparatus control system 70 to the reticle stage control system 40 and in response to an instruction from the reticle stage control system 40.
The position of the reticle stage 4 is measured by optical axis direction and horizontal direction position detection means such as a laser interferometer 101a and an encoder (not shown).
Further, although not shown, the reticle stage 4 is cooled by circulating a liquid such as pure water or directly blowing air or the like in order to suppress the heat generation of the reticle stage 4.

The cooling system of the reticle stage 4 includes a flow meter for monitoring the flow rate of liquid and air, a thermometer for monitoring temperature, and a hygrometer for monitoring humidity.
Similarly, since air is circulated in the reticle stage 4 space in order to keep the space temperature constant, a flow meter for monitoring the air flow rate, a thermometer for monitoring temperature, and a humidity monitor A hygrometer is configured.
The reticle stage 4 space also includes a barometer for monitoring the atmospheric pressure.
On the other hand, on the reticle reference plate 3, several kinds of reference marks (not shown) such as an optical axis direction on the reticle reference plate 3 and a mark for detecting a tilt position in a direction orthogonal to the optical axis are provided.
The projection optical system 5 is composed of a plurality of lenses, and at the time of exposure, the circuit pattern on the reticle 2 is imaged on the wafer 8 at a magnification corresponding to the reduction magnification of the projection optical system 5. The projection optical system 5 is controlled by the projection optical system control system 50.

The projection optical system 5 includes a laser interferometer and an encoder (not shown), and the position of each lens as a component is measured.
Further, although not shown, the projection optical system 5 includes a thermometer for monitoring the ambient temperature in the projection optical system 5, a hygrometer for monitoring the atmospheric humidity, and a barometer for monitoring the atmospheric pressure. It is configured.
The projection optical system 5 is also cooled by directly circulating a circulation of liquid such as pure water or air in order to dissipate the heat absorbed by the lens.
The cooling system of the projection optical system 5 includes a flow meter for monitoring the flow rate of liquid and air, and a flow meter for monitoring the flow rate of a gas purge such as N ₂ for the purpose of stabilizing the imaging performance. ing.

TTR (Through
The Reticle) type TTR observation optical system 20 has constituent elements 21, 22, 23, 24, and 25 described later.
The TTR observation optical system 20 has a first measuring means, and measures the position of the image plane of the projection optical system 5 in the direction of the optical axis of the projection optical system 5, so that the wafer as the projection optical system 5 and the substrate stage It is a means for measuring light through a reference plane arranged on the stage 10.
First, the illumination light beam emitted from the fiber 21 passes through the half mirror 22 and is condensed near the reticle reference plate 3 or the reticle 2 via the objective lens 23 and the mirror 24.
The illumination light beam condensed near the reticle reference plate 3 is condensed on the stage reference plate 9 via the projection optical system 5.
The reflected light from the stage reference plate 9 returns to the original optical path, and is sequentially reflected by the half mirror 22 via the projection optical system 5, reticle reference plate 3, mirror 24, and objective lens 23, and enters the image sensor 25.
The stage reference plate 9 is provided with an optical axis direction on the stage reference plate 9 and a mark for detecting a tilt position in a direction orthogonal to the optical axis.
Although not shown, a relay lens that changes the focal position with respect to the observation surface is configured in the TTR observation optical system 20 that is a TTR alignment scope.

The TTR observation optical system 20 includes an optical axis direction on the reticle reference plate 3 and a mark for detecting a tilt position in the direction orthogonal to the optical axis, and a mark for detecting a tilt position in the direction orthogonal to the optical axis direction and the optical axis on the stage reference plate 9. Measure.
Note that in an apparatus in which a plurality of reticle stages 4 and projection optical systems 5 are configured, a plurality of TTR observation optical systems 20 are configured according to the number of projection optical systems 5.
On the other hand, the TTR observation optical system 20 includes a thermometer for monitoring the atmospheric temperature, a hygrometer for monitoring the atmospheric humidity, and a barometer for monitoring the atmospheric pressure.
The TTR observation optical system 20 is cooled by directly circulating a liquid such as pure water or air in order to dissipate the heat absorbed by the objective lens and the relay lens.
Therefore, the TTR observation optical system 20 includes a flow meter for monitoring the flow rate of liquid and air, and a flow meter for monitoring the flow rate of a gas purge such as N ₂ for the purpose of stabilizing the imaging performance. Has been.
The positions of the objective lens 23 and the relay lens are measured by position detection means such as a laser interferometer and an encoder (not shown).

A light beam, which is non-exposure light emitted from the light projecting optical system 6, is collected and reflected on a point on the stage reference plate 9 or the upper surface of the wafer 8. The reflected light beam enters the detection optical system 7.
Although not shown, a position detection light-receiving element is arranged in the detection optical system 7 so that the position detection light-receiving element and the reflection point of the light beam on the stage reference plate 9 are conjugate.
The positional deviation of the stage reference plate 9 with respect to the optical axis direction of the projection optical system 5 is measured as the positional deviation of the incident light beam on the position detection light receiving element in the detection optical system 7.
The light projecting optical system 6 and the detection optical system 7 constitute an off-axis autofocus optical system.

Although not shown, a position detection mark corresponding to a pattern image formed via the projection optical system 5 is formed on the stage reference plate 9.
That is, the exposure light beam emitted from the light source 1 is illuminated via the illumination optical system or the TTR observation optical system 20 with respect to the mark drawn on the reticle 2 and the position detection mark drawn on the reticle reference plate 3. .
Therefore, a position detection mark (not shown) corresponding to the pattern image formed through the projection optical system 5 is formed on the stage reference plate 9 and is used for position detection.
The positional deviation amount from the reference surface of the stage reference plate 9 measured by the detection optical system 7 becomes clear in relation to the position detection mark and is transmitted to the wafer stage control system 60.

The wafer stage control system 60 drives the stage reference plate 9 up and down in the optical axis direction (z direction) of the projection optical system 5 in the vicinity of the reference position during focus calibration measurement, and also controls the position of the wafer 8 during exposure. carry out.
On the other hand, an off-axis type off-axis observation optical system 100 capable of observing and measuring the surface of the wafer 8 with non-exposure light is configured.
The off-axis observation optical system 100 constitutes a planar position detection unit that detects the position of the wafer stage 10 or the wafer 8 in the planar direction, and is controlled by the exposure apparatus control system 70.
The off-axis observation optical system 100 is a second measurement unit that measures the position of the target surface arranged on the substrate stage in the direction of the optical axis.
Further, the calibration of the previous two measuring means is performed based on the position of the image plane measured using the first measuring means and the position of the reference plane as the target surface measured by the second measuring means. Do.
Furthermore, the position of the surface of the substrate as the target surface arranged on the substrate stage is measured by the second measuring means that has been calibrated, and the substrate stage is positioned based on the measured position of the surface. .
Furthermore, the wafer 8 that is the substrate held on the positioned substrate stage is exposed through the reticle 2 that is the original.
The laser interferometer 101c described later constitutes a relative position measuring unit that measures a change in the relative position of the off-axis observation optical system 100 in the planar direction position detecting unit when the exposure process is not performed. .

The off-axis observation optical system 100 includes a thermometer for monitoring the atmospheric temperature, a hygrometer for monitoring the atmospheric humidity, and a barometer for monitoring the atmospheric pressure.
The wafer stage 10 is movable in the optical axis direction (z) of the projection optical system 5 and in the directions (x, y) orthogonal to the projection optical system 5 in the scanning exposure apparatus, and is rotated with respect to the optical axis and pitched in the scanning direction. It is also possible to change the yawing.
Regarding the drive control of the wafer stage 10, an instruction from the exposure apparatus control system 70 is transmitted to the wafer stage control system 60, and the wafer stage 10 is driven and controlled by an instruction from the wafer stage control system 60.
The wafer stage 10 is measured for the position of the wafer stage 10 by means of optical position and horizontal position detection means and relative position measurement means such as laser interferometers 102 and 103 and an encoder (not shown).
Although not shown, the wafer stage 10 is cooled by circulating a liquid such as pure water or directly blowing air or the like in order to suppress the heat generation of the wafer stage 10.
For this reason, a flow meter for monitoring the flow rate of the cooling liquid or air and a thermometer for monitoring the temperature are configured.

Air is also circulated in the space of the wafer stage 10 in order to keep the space temperature constant.
Therefore, a flow meter for monitoring the air flow rate, a thermometer for monitoring the temperature, a hygrometer for monitoring the humidity, and a barometer for monitoring the atmospheric pressure are configured in the wafer stage 10 space as well. Has been.

For the measurement by the relative position measuring means, either the storage means 70a for storing the measurement results by the plurality of orthogonal direction inclination position detecting means 101a at the focal position of the existing exposure processing or one orthogonal direction inclination position detecting means is used.
The relative position measuring means drives the constituent units in the exposure apparatus in the direction perpendicular to the optical axis direction and the optical axis inclination direction based on the measurement result at the focal position of the existing exposure process stored in the storage means 70a.
Further, the measurement is performed by an orthogonal direction inclination position detection unit other than one orthogonal direction inclination position detection unit.
The above-described constituent units include, for example, the reticle 2, the reticle stage 4, the wafer 8, which is the substrate, the wafer stage 10, the projection optical system 5, the TTR observation optical system 20, the constituent elements in the TTR observation optical system 20, and the off-state. -Axis observation optical system 100 or the like.
A laser interferometer 102 is installed above each of the edge side near the stage reference plate 9 and the edge side near the wafer 8 in the Y-axis direction of the wafer stage 10 during the non-exposure processing of the wafer 8 as a substrate. Has been.

Further, a laser interferometer 102 is also provided below the center side of the back side of the wafer stage 10 during the non-exposure processing of the wafer 8 in the Y-axis direction.
Each laser interferometer 102 measures the tilt state of the wafer stage 10 and the like, and is one of the relative position measuring means for measuring the relative position change of the wafer stage 10 when the exposure process is not performed. Configure one.
A laser interferometer 103 is installed near the outer side of the side surface of the wafer stage 10 near the stage reference plate 9.
The laser interferometer 103 detects the position of the wafer stage 10 in the horizontal direction, and is one of relative position measuring means for measuring a change in the relative position of the wafer stage 10 when exposure processing is not performed. Configure.

On the other hand, the exposure apparatus control system 70 includes a CPU that executes various controls and a storage unit 70a that stores various control programs including various measurement information and correction control programs. Various control programs will be described later.
The exposure apparatus control system 70 constitutes a determination means that automatically determines the presence / absence of temporal change of each component and each component in the exposure apparatus based on the measurement results by the planar direction position detection means and the relative position measurement means. .
This determination means has a calculation means, and outputs the first measurement means after calibration in a state where the reference surface is positioned by the substrate stage, and the second measurement means that uses the reference surface in the state as the target surface. It calculates based on the output after the calibration.
The calculating unit further calculates a relative change amount after the calibration between the output of the first measuring unit and the output of the second measuring unit.
Further, the reference surface is positioned based on the output of one of the first measuring means and the second measuring means, and the other output of the first measuring means and the second measuring means is output in the positioned state. obtain.
Further, the calculation means has storage means for storing the relationship between the output of the first measurement means and the output of the second measurement means when the calibration is performed, and the one output and the other And the relative change amount is calculated based on the relationship stored in the storage means.
The exposure apparatus control system 70 includes a configuration as a correction measurement control means 70b that performs correction measurement based on a result determined by the exposure apparatus control system 70 that is a determination means.
Targets of correction measurement based on the exposure apparatus control system 70 are arbitrary constituent elements and constituent units such as the wafer stage 10 and the TTR observation optical system 20 in the exposure apparatus.
Note that the laser interferometers 101a to 101c, 102, 103, and the off-axis observation optical system 100 are also included in the configuration as the correction measurement control unit.
The exposure apparatus control system 70 executes high-precision exposure processing by correcting and controlling each component and each unit of the exposure apparatus based on the correction value based on the correction measurement.

FIG. 2 is a flowchart showing an example of a program used by the exposure apparatus control system 70, which is a correction measurement sequence for a change with time in the optical axis direction and the inclination in the direction orthogonal to the optical axis.
Here, with reference to FIG. 2, a plurality of optical axis directions configured in the exposure apparatus and a relative position change of the inclination position detecting means orthogonal to the optical axis are measured to determine whether or not the apparatus has changed over time. A specific method for automatically controlling the execution of correction measurement will be described.
In the correction measurement, using the TTR observation optical system 20, the optical axis direction on the reticle reference plate 3 and the orthogonal tilt position detection mark on the reticle reference plate 3 and the optical axis direction on the stage reference plate 9 and the optical axis orthogonal to each other. The direction inclination position detection mark is measured.
In the measurement preparation necessary for the correction measurement, the objective lens 23 of the TTR observation optical system 20 is driven, the illumination optical system is guided to the TTR observation optical system 20, and the marks on the reticle reference plate 3 are measured. The drive of the reticle stage is complete.
It is also assumed that driving of the wafer stage 10 for measuring the mark on the stage reference plate 9 has already been completed.

After the above, first, in step S10, the relay lens (not shown) of the TTR observation optical system 20 is driven to the measurement start position.
In step S15 in FIG. 2, the position detection mark on the reticle 2 side is measured. The measurement of the position detection mark on the reticle 2 side means the measurement of the contrast or light quantity of the position detection mark by the configuration of the TTR observation optical system 20.
In step S20, the completion of measurement is confirmed. If the measurement has not been completed, the focus position of the relay lens is changed in step S25, the process returns to step S10, and the above processing is repeated.
When the measurement of all the measurement targets is completed, in step S30, the optimal position in the optical axis direction and the inclination in the direction orthogonal to the optical axis are calculated, that is, the optimal focal position is calculated.
Here, the optimum position in the optical axis direction is the optimum focal position of the TTR observation optical system 20 with respect to the position detection mark on the reticle 2 side.
The inclination in the direction orthogonal to the optical axis is the inclination in the direction orthogonal to the optical axis calculated from the optimum optical axis position calculated in each of the left and right TTR observation optical systems 20 and the span of the left and right TTR observation optical systems 20. .

Next, in step S35, the relay lens is driven to the optimum position in the optical axis direction. When the driving is completed, the position in the optical axis direction of the TTR observation optical system 20 with respect to the position detection mark on the reticle 2 side is optimized.
In step S40, the optimum focus state is stored. Here, the measurement values of a plurality of optical axis direction position detection systems at the optimum optical axis direction position are stored.
For example, the reading values of the laser interferometer 101a and the encoder that control the position in the optical axis direction of the reticle stage 4 and the tilt in the direction orthogonal to the optical axis based on the output result are stored.
Second, the laser interferometer 101b that controls the position of the relay lens in the optical axis direction and the readings of the encoder are stored.
Third, the number of pulses of the motor that drives the relay lens, the light amount value and the contrast value, which are measured values of the optical axis position of the TTR observation optical system 20, are stored.
Furthermore, since the atmospheric pressure, temperature, and humidity are factors that change the focal position as environmental factors in the apparatus, the flow rate and temperature of the air or liquid in the reticle stage 4 and the reticle stage space and the TTR observation optical system 20, Humidity and atmospheric pressure values are also stored.

In step S45, the position detection mark on the wafer 8 side is driven to the measurement position.
Here, the reason for driving the position detection mark on the wafer 8 side to the measurement position is that if the wafer 8 side mark surface is under the TTR observation optical system 20, the reflected light from the wafer 8 surface enters the TTR observation optical system 20. It is because it ends up.
When reflected light from the surface of the wafer 8 is incident on the TTR observation optical system 20, it is not preferable from the viewpoint of work efficiency because the wafer stage 10 needs to be temporarily driven to a place where there is no reflective surface.
However, step S45 may be omitted when the processes of steps S10 to S30 are not performed.
In step S50, the position detection mark on the wafer 8 side is measured. The measurement of the position detection mark on the wafer 8 side is performed by measuring the contrast or light quantity by the configuration of the TTR observation optical system 20.

In step S55, it is confirmed whether or not the measurement of the position detection mark on the wafer 8 side is completed.
If the measurement of the position detection mark on the wafer 8 side has not been completed, the optical axis direction position of the Z stage configured in the wafer stage 10 is changed in step S60, the focal position of the Z stage is changed, and the step Return to S50.
After all the measurements are completed, in step S65, the optimal position in the optical axis direction and the inclination in the direction orthogonal to the optical axis are calculated, that is, the most focal position is calculated.
Here, the optimum position in the optical axis direction refers to the optimum focal position of the position detection mark on the wafer 8 side with respect to the position detection mark on the reticle 2 side.
The inclination in the direction orthogonal to the optical axis is the inclination in the direction orthogonal to the optical axis calculated from the optimum optical axis position calculated in each of the left and right TTR observation optical systems 20 and the span of the left and right TTR observation optical systems 20. .

In step S70, the Z stage is driven to an optimal position in the optical axis direction and an inclined position orthogonal to the optimal optical axis.
When the driving is completed, the position in the optical axis direction of the position detection mark on the wafer 8 side and the inclination in the direction orthogonal to the optical axis with respect to the position detection mark on the reticle 2 side are optimized.
In step S75, the optimum focus state is stored. Here, a plurality of optical axis directions at the optimum position in the optical axis direction and measurement values of the tilt position detection system orthogonal to the optical axis are stored.
For example, the laser interferometers 102 and 103 for controlling the optical axis direction of the wafer stage 10 and the orthogonal tilt position with respect to the optical axis based on the output result, the reading value of the encoder, and the reading value of the off-axis autofocus detection optical system are stored. To do.
Further, the light amount value and contrast value, which are optical axis position measurement values of the TTR observation optical system 20, and the laser interferometer 101b for controlling the position of each lens of the projection optical system based on the output result, and the reading value of the encoder Remember.
In addition, since atmospheric pressure, temperature, and humidity are factors that change the focal position as environmental factors in the apparatus, the flow rate and temperature of air or liquid in the wafer stage 10 and the wafer stage space, the projection optical system, and the TTR observation optical system 20 Memorize the humidity and pressure values.

FIG. 3 is a flowchart showing another example of a program used by the exposure apparatus control system 70, which is a measurement sequence for measuring a change in the relative position of the optical axis direction and an inclination direction detecting unit orthogonal to the optical axis.
Here, an example will be described in which the presence / absence of time-dependent changes in the optical axis direction of the position detection mark on the wafer 8 side relative to the position detection mark on the reticle 2 side and the inclination direction orthogonal to the optical axis is described.
First, in step S100, the reticle stage 4 and the wafer stage 10 are driven to the optimum focal position stored.
The stored optimal focus position refers to the optimal focus position stored in step S40 and step S75 in FIG.

Driving to the optimum focus position means that the reticle stage 4 is at a height that is the value of the laser interferometer 101a or the encoder stored in the optical axis direction of the reticle stage 4 and the inclination direction orthogonal to the optical axis. Refers to the drive adjustment.
Secondly, the drive adjustment of the relay lens to the position where the optical axis direction position of the relay lens of the TTR observation optical system 20 becomes the value of the stored laser interferometer 101b or encoder.
Thirdly, the lens position in the projection optical system 5 is adjusted to a position where the lens position in the projection optical system 5 becomes the value of a stored laser interferometer or encoder (not shown).
Fourth, drive adjustment of the height of the wafer stage 10 to a position where the optical axis direction of the wafer stage 10 and the tilt direction orthogonal to the optical axis become the values of the stored laser interferometers 102 and 103 or the encoder. Point to.

In step S105, measurement is performed using an optical axis direction and a tilt position detecting unit orthogonal to the optical axis.
That is, in the first embodiment, measurement is performed by the autofocus detection optical system including the off-axis projection optical system 6 and the detection optical system 7 and the TTR observation optical system 20.
The off-axis autofocus detection optical system measures the height and tilt of the wafer stage 10.
The TTR observation optical system 20 measures the light quantity or contrast of the position detection mark on the wafer stage 10 side.
In step S110, a plurality of optical axis directions and a relative change in the detection result of the inclination direction detecting unit orthogonal to the optical axis are compared.
In order to determine whether or not there is a change with time in the wafer stage space, the relationship between the height and inclination of the wafer stage 10 in the optical axis direction and the detection result of the off-axis autofocus detection optical system may be viewed.

By the way, by step S100, the drive adjustment to the values of the laser interferometers 102 and 103 or the encoders, which are the optimum focal positions stored in the optical axis direction height and inclination of the wafer stage 10, is completed.
For this reason, if the wafer stage 10 does not change with time, it is driven to an optimum focal position.
In step S105, the height and inclination of the wafer stage 10 are measured by an off-axis autofocus detection optical system.
If the off-axis autofocus detection optical system has not changed over time, the measured value is the same as the stored measurement value of the off-axis autofocus detection optical system.
In step S115, it is determined whether or not there is a relative change in the detection results of the plurality of optical axis directions and the orthogonal inclination position detection means with respect to the optical axis.
If the respective detection results have the same value, it is determined that there is “no change with time”, and the process proceeds to step S125.
However, if the measured value of the off-axis autofocus detection optical system is different from the stored value, it is determined that either the wafer stage 10 or the off-axis autofocus detection optical system has changed over time, and step S120. Proceed to

Similarly, in order to determine whether or not there is a change with time in the wafer stage space or the projection optical system space, the height and inclination of the wafer stage 10 in the optical axis direction, each lens position in the projection optical system 5, and TTR observation. What is necessary is just to look at the relationship of the optical system 20.
That is, in step S100, the height and inclination of the wafer stage in the optical axis direction are driven to the optimum focal position stored based on the value of the laser interferometer or encoder.
Similarly, driving is completed based on the value of the laser interferometer or encoder at the optimum focal position that stores the lens positions in the projection optical system 5, and the wafer stage 10 and the projection optical system 5 change over time. If there is no, it is driven to the optimum focus position.
Further, the light quantity or contrast of the position detection mark on the wafer 8 side is measured by the TTR observation optical system 20.
For this reason, if the TTR observation optical system 20 has not changed over time, the light amount or contrast value is the same as the stored light amount or contrast value of the TTR observation optical system 20.

Here, also when the light amount or the contrast value of both TTR observation optical systems 20 are the same value, it is determined that “no change with time”, and the process proceeds to step S125.
However, if the light amount or contrast value of the TTR observation optical system 20 is different from the stored value, it is assumed that any one of the wafer stage 10, the projection optical system 5, or the TTR observation optical system 20 has changed over time. Determine and proceed to step S120.
Thus, in step S120, it is confirmed that “there is a change with time”, and “there is a change with time” is displayed on the display or the like.
On the other hand, in step S125, “no change with time” is confirmed, and “no change with time” is displayed on the display or the like.

An optical axis direction such as the laser interferometers 101a to 101c, 102 and an off-axis autofocus detection optical system and a tilt position detecting means orthogonal to the optical axis is sensitive to environmental factors such as temperature, humidity, and atmospheric pressure. have.
For this reason, when the stored temperature, humidity, and pressure at the optimum focal position are different from the current values, correction is performed in consideration of sensitivity.
As described above, in the present invention, the optical axis direction of the reticle stage 4 or the like and the tilt direction orthogonal to the optical axis based on the stored optimum focal position information are the optical axis direction and optical axis of the laser interferometer or encoder. Measured by means for detecting the inclination position in the orthogonal direction.
With the wafer stage 10 or the like being driven to the optimal focal position that has been measured and stored, an off-axis autofocus detection optical system and a TTR observation optical system 20, such as an optical axis direction and an orthogonal tilt position detection means for the optical axis. use.
However, the optical axis direction and the optical axis direction orthogonal inclination position detection means measure the optical axis direction and the orthogonal direction inclination position with the optical axis, and make a relative comparison with the stored optimum focal position information. This makes it possible to determine whether or not there is a change with time in the apparatus.
That is, in the first embodiment, the optical axis direction of the stages 4 and 10 and the tilt position in the direction orthogonal to the optical axis are driven and adjusted according to the values of the laser interferometer 101a and the like, and the off-axis autofocus detection optical system or the TTR observation optical system 20 is adjusted. Measure and memorize.

In the first embodiment, the relative value is compared with the stored measurement value as an example. However, the relative value comparison of the present invention is not limited to this.
For example, the TTR observation optical system 20 may perform measurement by driving and adjusting the optical axis direction of the stages 4 and 10 and the orthogonal tilt position with respect to the optical axis according to the value of the off-axis autofocus detection optical system.
Further, for example, the stages 4 and 10 may be driven to the optical axis direction and a position inclined in the direction orthogonal to the optical axis according to the value of the off-axis autofocus detection optical system, and measurement by the off-axis observation optical system 100 may be performed. good.
Alternatively, in order to determine whether or not the apparatus has changed over time, a wafer-side mark or a reticle-side mark, which is a measurement object, is stored according to any one of the optical axis direction and one orthogonal direction tilt position detection means with respect to the optical axis. The drive is adjusted to the optimum focus position.
And the method of measuring by the orthogonal | vertical direction inclination position detection means other than one orthogonal direction inclination position detection means with respect to an optical axis direction and an optical axis, and measuring the presence or absence of the measured value with the memorize | stored value Is also preferable. That is, it is sufficient if the difference between the measured value and the stored value can be measured or determined.

FIG. 4 is a flowchart showing yet another example of a program used by the exposure apparatus control system 70, which is an exposure processing sequence including determination of whether or not there is a change with time in the optical axis direction and the orthogonal tilting apparatus with respect to the optical axis. .
After completion of the previous Lot processing, in step S200, measurement of relative position changes such as the reticle stage 4, the wafer stage 10, the off-axis autofocus detection optical system, the TTR observation optical system 20 and the like as the constituent units is performed. carry out.
Since the measurement of the relative change in each relative position has been described above, a detailed description thereof will be omitted here.
In step S205, it is confirmed whether or not there is a relative change in the measurement of the relative change, that is, whether or not there is a relative position change.
Here, if there is a relative position change, it is necessary to carry out correction measurement of the change with time of the apparatus before the next exposure processing, and therefore, in Step S210, Flag indicating execution of correction measurement is set to “On”. "
However, if there is no change in the relative position, it is not necessary to carry out correction measurement of the change with time of the apparatus before the next exposure processing, so in step S215 Flag indicating that non-correction measurement is performed is set to “Off”. To do.

Here, the relative position change measurement timing in step S200 is set to be after the end of the previous lot process and before the start of the next lot process.
However, after the start of the next lot process shown in FIG. 4, the reticle 2 supply in step S220 and the wafer 8 supply in step S225 are processed in parallel.
However, since the supply completion timings of the reticle 2 and the wafer 8 are not necessarily the same, the relative position change measurement is performed with priority given to the reticle 2 or the like that has been supplied first. Also good.
In addition, while the lot process is being performed, the wafer 8 is frequently replaced, but the reticle 2 is not always replaced at the wafer 8 replacement timing.
That is, since it is possible to perform relative position change measurement at a timing at which reticle 2 replacement does not occur, the relative position change measurement timing is not limited from the end of Lot processing to the start. .
That is, the relative position change measurement of various structural units including the reticle 2 and the wafer 8 may be performed at any timing that does not give a delay to the exposure process or any timing that can tolerate the delay. .

In step S230, the state of Flag indicating the necessity of performing correction measurement of change over time is confirmed. If Flag is “On”, the correction measurement of the temporal change is performed in step S235.
The details of the correction measurement of the change over time have already been described with reference to FIG.
In step S240, alignment measurement is performed. When the alignment measurement is performed, the measurement process is performed in a state in which the change with time of each constituent unit of the exposure apparatus is corrected, so that highly accurate alignment measurement is performed.
In step S245, an exposure process is performed. Although not shown, the exposure process is performed while repeating the wafer 8 exchange and the reticle 2 exchange until the Lot process is completed.
In the first embodiment, whether or not there is a change with time of each constituent unit in the exposure apparatus is determined when the exposure process is not performed, and when there is a change with time, correction measurement of the change with time is performed immediately before exposure. As a result, the apparatus can be operated efficiently and with high accuracy.
For this reason, the exposure apparatus of Example 1 can reduce the time spent for maintenance work and the correction measurement time required during the exposure process.

Next, a second embodiment of the present invention will be described.
In the present embodiment, the relative position changer in the non-exposure process is used to detect changes in the relative positions of the TTR observation optical system 20 and the off-axis observation optical system 100, which are a plurality of planar position detection means for detecting the position in the planar direction. It measures with the laser interferometer 101c etc. which are.
The TTR observation optical system 20 as the first measuring means is a means for measuring the position of the reference mark arranged on the wafer stage 10 as the substrate stage via the projection optical system 5.
The off-axis observation optical system 100 as the second measuring means is means for measuring the position of the target mark placed on the substrate stage without using the projection optical system 5.
Further, based on the position of the reference mark measured using the first measuring means and the position of the reference mark as the target mark measured using the second measuring means, the second measuring means Perform calibration.
Further, the position of the alignment mark as the target mark placed on the substrate held on the substrate stage is measured by the second measuring means that has been calibrated, and the substrate is based on the position of the measured alignment mark. Position the stage.
As a result, the wafer 8 that is the substrate held on the positioned substrate stage is exposed through the reticle 2 that is the original.
Based on the measurement result, the presence / absence of a temporal change in the planar position detecting means which is a constituent unit of the apparatus is automatically determined by an exposure apparatus control system 70 as a determining means.
The exposure apparatus control system 70 has calculation means, and uses the output after the calibration of the first measurement means in a state where the reference mark is positioned by the substrate stage and the reference mark in the state as the target mark. It calculates based on the output after the calibration of the second measuring means.
Further, a relative change amount after the calibration between the output of the first measuring unit and the output of the second measuring unit is calculated.
Further, the reference plane is positioned based on the output of one of the first measuring means and the second measuring means, and the other output of the first measuring means and the second measuring means is positioned in the positioned state. Get.
The calculating means has storage means for storing the relationship between the output of the first measuring means and the output of the second measuring means when the calibration is performed, and the one output, the other output, The relative change amount is calculated based on the relationship stored in the storage means.
Here, there is an informing means for informing that the calculated relative change amount exceeds the allowable amount, and the calibration is performed when the calculated relative change amount exceeds the allowable amount. .
The exposure apparatus control system 70 includes a configuration of correction measurement control means 70b that performs correction measurement.
Also in this embodiment, for relative position measurement, either the storage unit 70a for storing the measurement results of the plurality of plane direction position detection units at the plane direction position of the existing exposure process or one of the plane direction position detection units. Is used.
Then, the position of the plane direction position detecting means, which is a constituent unit in the exposure apparatus, is driven in the plane direction based on the measurement result at the position in the plane direction of the existing exposure process stored in the storage means 70a, and the other position in the plane direction Measure with the detection means.

In the second embodiment, relative position changes of a plurality of optical axis direction and plane direction position detecting means configured in the exposure apparatus are measured, and whether or not the apparatus has changed over time is determined and correction measurement is automatically performed. A specific method of controlling will be described.
Note that the planar position detection means includes a TTR observation optical system 20 and an off-axis observation optical system 100.
FIG. 5 is a flowchart showing still another example of the control program of the exposure apparatus control system 70, which is a correction measurement sequence for correcting the change with time of the planar direction position detecting means.
In the correction measurement in the second embodiment, the TTR observation optical system 20 is used to measure the plane direction position detection mark on the reticle reference plate 3 and the plane direction position detection mark on the stage reference plate 9.
The planar position detection marks on both the reticle reference plate 3 and the stage reference plate 9 are hereinafter abbreviated as position detection marks.
In this embodiment, as the measurement preparation necessary for the correction measurement, the driving of the objective lens 23 of the TTR observation optical system 20 and the driving of the illumination optical system for guiding the light to the TTR observation optical system 20 are already completed. .
Further, driving of the reticle stage 4 for measuring the position detection mark on the reticle reference plate 3, driving of the wafer stage 10 for measuring the position detection mark on the stage reference plate 9, and the like have already been completed. Shall.

First, in step S300, the relay lens of the TTR observation optical system 20 is driven to the optimum focal position for the position detection mark on the reticle reference plate 3. Since the detailed explanation of the optimum focus position measurement has been described above, it will be omitted.
In step S305, the Z stage of the wafer stage 10 is driven to the optimum focal position. Since the detailed explanation of the optimum focus position measurement has been described above, it will be omitted. Steps S300 and S305 are processed in parallel.
Note that steps S300 and S305 are performed to obtain the optimum focal position of the measurement mark immediately before in order to measure the planar position measurement with high accuracy, but the optical axis direction position has not changed over time. May be omitted.
In step S310, the measurement of the planar direction positions of the reticle 2, the wafer 8, the reticle reference plate 3, the stage reference plate 9, the TTR observation optical system 20, the off-axis observation optical system 100, etc. is performed as a constituent unit.

In step S315, the planar direction position of each component unit is calculated. When the TTR observation optical system 20 is configured with a two-dimensional CCD, the following calculation is performed with respect to the center of the CCD.
That is, the positional deviation amount of the position detection mark on the reticle 2 side and the positional deviation amount of the position detection mark on the wafer 8 side, or the relative positional deviation between the position detection mark on the reticle 2 side and the position detection mark on the wafer 8 side. Calculate the amount.
Detection of the position of the pattern drawn on the wafer 8 in the plane direction is performed by the off-axis observation optical system 100.
The positional deviation amount of the measurement mark on the wafer 8 with respect to the off-axis observation optical system 100 is calculated.
In step S320, the planar direction state of each component unit is stored. Here, the measurement values of the TTR observation optical system 20 and the off-axis observation optical system 100 which are a plurality of planar direction position detection means are stored.
For example, the reading values of the laser interferometer 101a and the encoder that control the planar position of the reticle stage 4 based on the output result and the reading values of the laser interferometer 101b and the encoder that control the planar position of the objective lens 23 are stored.
Furthermore, the reading value of the laser interferometer 101c that measures the planar position of the off-axis observation optical system 100 is stored.
Further, the number of pulses of the motor that drives the objective lens 23 of the TTR observation optical system 20 and the amount of positional deviation that is a planar position measurement value of the TTR observation optical system 20 are stored.
In addition, the laser interferometers 102 and 103 that control the planar direction position of the wafer stage 10 based on the output result and the reading values of the encoder and the laser interferometer that controls the position of each lens of the projection optical system 5 based on the output result Store the encoder reading.
In addition, since atmospheric pressure, temperature, and humidity are factors that change the focal position as environmental factors in the apparatus, the flow rate of air or liquid in the wafer stage 10 and the wafer stage space, the projection optical system 5 and the TTR observation optical system 20 Also stores temperature, humidity, and barometric pressure values.

FIG. 6 shows still another program for the exposure apparatus control system 70 which is a measurement sequence for measuring a relative position change of the TTR observation optical system 20 and the off-axis observation optical system 100 which are planar position detection means. It is a flowchart which shows an example.
Here, the measurement of whether or not the position in the plane direction of the position detection mark on the wafer 8 side with respect to the position detection mark on the reticle 2 side changes with time will be described as an example.
First, in step S350, each component unit is driven to a stored planar position. The stored plane direction position refers to the plane direction position stored in step S320 in FIG.
In the driving to the plane direction position, X, Y, and θ of the reticle stage 4 are driven and adjusted to the position that becomes the value of the stored laser interferometer 101a or encoder as the plane direction position of the reticle stage 4.
Further, the objective lens 23 is driven and adjusted to a position that becomes the value of the stored laser interferometer 101b or encoder as the position in the plane direction of the objective lens 23 of the TTR observation optical system 20.
Further, the lens in the projection optical system 5 is driven and adjusted to a position that becomes the value of the stored laser interferometer or encoder as the position in the plane direction of the projection optical system 5.
Further, the X, Y, and θ of the wafer stage 10 is driven and adjusted to the position that becomes the value of the stored laser interferometers 102 and 103 or the encoder as the planar direction position of the wafer stage 10.

In step S355, measurement using the planar position detection means is performed. That is, measurement is performed by the TTR observation optical system 20 and the off-axis observation optical system 100 constituting the planar direction position detection means.
The measurement by the off-axis observation optical system 100 measures the amount of positional deviation of the position detection mark on the wafer stage 10 side with respect to the position reference of the off-axis observation optical system 100.
The measurement by the TTR observation optical system 20 is performed by measuring the amount of positional deviation of the reticle 2 side position detection mark with respect to the position reference of the TTR observation optical system 20 and the position deviation of the wafer stage 10 side position detection mark with respect to the position reference of the TTR observation optical system 20. Measure the amount.
The measurement by the TTR observation optical system 20 or the relative positional deviation amount between the reticle 2 side position measurement mark and the wafer 8 side position detection mark is measured.

In step S360, the measurement results of the plurality of planar direction position detecting means are relatively compared.
For example, in order to determine whether or not there is a change with time in the wafer stage space, the relationship between the planar position of the wafer stage 10 and the off-axis observation optical system 100 may be viewed.
That is, in step S350, the planar position of the wafer stage 10 has been driven based on the value of the laser interferometer 103 or the encoder in the stored planar direction position.
If the wafer stage 10 has not changed over time, the position of the position detection mark on the wafer 8 side is driven to the same position as the existing measurement position with respect to the position reference of the off-axis observation optical system 100.
On the other hand, in step S355, the off-axis observation optical system 100 measures the positional deviation of the position detection mark on the wafer 8 side with respect to the position reference of the off-axis observation optical system 100.
If the off-axis observation optical system 100 has not changed over time, the measured value is the same as the stored value measured by the off-axis observation optical system 100.

In step S365, it is confirmed whether or not there is a relative change in each value as a result of the relative comparison of the measurement results of the plurality of planar direction position detection units in step S360.
If the values are the same as a result of the confirmation, it is determined that there is “no change with time”, and the process proceeds to step S375.
However, if the measured value of the off-axis observation optical system 100 is different from the stored value, it is determined that either the wafer stage 10 or the off-axis observation optical system 100 has changed over time, Proceed to step S370.
Similarly, in order to determine whether or not there is a change over time in the reticle stage space or the projection optical system space, the relationship between the TTR observation optical system 20 and the position in the plane direction of the reticle stage 10 and each lens position in the projection optical system 5. Just look at it.
In step S350, the driving of the reticle stage 4 is completed based on the value of the laser interferometer 101a or the encoder in the stored plane direction position.

Similarly, driving of each lens position in the projection optical system 5 is completed at the stored position based on the value of the laser interferometer or encoder.
If the reticle stage 4 and the projection optical system 5 have not changed over time, the position of the wafer 8 side position detection mark relative to the position reference of the TTR observation optical system 20 or the reticle 2 side position detection mark is the same as the existing measured position. Driven to the same position.
Here, when measuring the relative positional deviation with respect to the wafer 8 side position detection mark, it is assumed that the wafer stage space has not changed over time due to the relationship between the wafer stage 10 and the off-axis observation optical system 100 described above. It becomes.
In step S355, the TTR observation optical system 20 measures the positional deviation of the reticle 2 side position detection mark with respect to the position reference of the TTR observation optical system 20 or the positional deviation of the wafer 8 side position detection mark with respect to the reticle 2 side position detection mark. ing.
If the TTR observation optical system 20 has not changed over time, the measured value is stored in the TTR observation optical system 20 or the relative displacement between the wafer 8 side position detection mark and the reticle 2 side position detection mark. The amount is the same value.

Therefore, it is confirmed in step S365 that the values are the same. If the values are the same, it is determined that there is no change with time, and the process proceeds to step S375.
However, if the measured value of the TTR observation optical system 20 or the relative positional deviation amount between the wafer stage 10 side position detection mark and the reticle 2 side position detection mark is different from the stored value, it changes over time. Determination is made and the process proceeds to step S370.
That is, it is determined that any one of the reticle stage 4, the projection optical system 5, and the TTR observation optical system 20 that is a constituent unit has changed with time, and the process proceeds to step S370.
On the other hand, the planar position detecting means such as the laser interferometers 101a to 101c, 102, 103, the TTR observation optical system 20 and the off-axis observation optical system 100 have sensitivity to environmental factors such as temperature, humidity, and atmospheric pressure. ing.
For this reason, when the stored temperature, humidity, and pressure at the time of acquiring the planar position are different from the current value, correction is performed in consideration of sensitivity.

That is, as described above, the focal position of the reticle stage 4 or the like is driven to the stored planar direction position by the planar position detecting means such as the laser interferometer 101a or the encoder based on the stored planar direction position information (step S350).
Then, in the driven state, the planar position is measured by a planar position detector different from the planar position detector used for driving control, such as the off-axis observation optical system 100 and the TTR observation optical system 20 (step S355). ).
By comparing the measurement result with the stored planar direction position information (step S360), it is determined whether or not there is a change with time in the apparatus (step S365).
After the above, in step S370, it is determined that “there is a change with time” and, for example, “there is a change with time” is displayed on the display or the like.
On the other hand, in step S375, “no change with time” is confirmed, and for example, “no change with time” is displayed on the display or the like.

In the second embodiment, the planar position of the stages 4 and 10 is driven and adjusted according to the values of the laser interferometer 101a and the like, the measurement of the TTR observation optical system 20 is performed, and the relative value with the stored measurement value is compared. I took this as an example.
However, the relative value comparison of the present invention is not limited to this. For example, the position in the plane direction of the stages 4 and 10 is driven and adjusted according to the value of the off-axis observation optical system 100, and the measurement by the laser interferometer 101a or the like is performed. May be implemented.
That is, in order to determine whether or not the apparatus has changed over time, first, the position in the plane direction in which the position detection marks on the wafer 8 side and the reticle 2 side, which are measurement objects, are stored in accordance with any plane direction position measuring means. Adjust the drive.
Then, it is sufficient if measurement is performed by the TTR observation optical system 20 and the off-axis observation optical system 100 which are other planar direction position measurement means, and whether or not there is a difference between the measured values and the stored values can be measured. .
Note that the above-described flowchart shown in FIG. 4 can be applied to the exposure processing sequence flow including the determination of whether there is a change in the planar direction of the constituent units over time, but the details of this point are omitted because they are described above. To do.
As described above, in the second embodiment, the presence or absence of a change with time of the planar position measuring unit in the exposure apparatus is determined when the exposure process is not being performed. As a result, the apparatus can be operated efficiently and with high accuracy.
For this reason, the exposure apparatus of Embodiment 2 can also reduce the time spent for maintenance work and the correction measurement time required during the exposure process.

(Example of device manufacturing method)
Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described with reference to FIGS.
FIG. 7 is a flowchart for explaining the manufacture of semiconductor chips such as IC and LSI, and devices such as LCD and CCD. Here, a semiconductor chip manufacturing method will be described as an example.
The method comprises the steps of exposing a wafer using an exposure apparatus and developing the wafer, and specifically comprises the following steps.
In step S1 (circuit design), a semiconductor device circuit is designed.
In step S2 (mask production), a mask (reticle) is produced based on the designed circuit pattern.
In step S3 (wafer manufacture), a wafer is manufactured using a material such as silicon.
Step S4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by using the mask and the wafer by the above exposure apparatus using the lithography technique.
Step S5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer manufactured in step S4.
This process includes assembly processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation).
In step S6 (inspection), inspections such as an operation check test and a durability test of the semiconductor device manufactured in step S5 are performed.
Through these steps, the semiconductor device is completed and shipped (step S7).

FIG. 8 is a detailed flowchart of the wafer process in Step 4.
In step S11 (oxidation), the surface of the wafer is oxidized.
In step S12 (CVD), an insulating film is formed on the surface of the wafer.
In step S13 (electrode formation), an electrode is formed on the wafer.
In step S14 (ion implantation), ions are implanted into the wafer.
In step S15 (resist process), a photosensitive agent is applied to the wafer.
In step S16 (exposure), the circuit pattern of the mask is exposed onto the wafer by the exposure apparatus.
In step S17 (development), the exposed wafer is developed.
In step S18 (etching), portions other than the developed resist image are removed.
In step S19 (resist stripping), the resist that has become unnecessary after the etching is removed.
By repeatedly performing these steps, multiple circuit patterns are formed on the wafer.
Since the device manufacturing method of the present embodiment uses the above exposure apparatus, the efficiency of device manufacturing can be improved.

It is a block diagram which shows schematic structure of the exposure apparatus of Example 1 of this invention. It is a flowchart which shows the correction | amendment measurement sequence of the time-dependent change of the optical axis direction of Example 1 of this invention, and an orthogonal direction inclination with an optical axis. It is a flowchart which shows the measurement sequence which measures the relative position change of the optical axis direction position detection system in the exposure apparatus of Example 1 of this invention. It is a flowchart which shows the exposure sequence including determination of the presence or absence of a time-dependent change in the exposure apparatus of Example 1 of this invention. It is a flowchart which shows the correction | amendment measurement sequence which correct | amends the time-dependent change of the plane direction apparatus in the exposure apparatus of Example 2 of this invention. It is a flowchart which shows the measurement sequence which measures the change of the relative position of the planar direction position detection system in the exposure apparatus of Example 2 of this invention. It is a flowchart for demonstrating the device manufacturing method using the exposure apparatus of this invention. It is a detailed flowchart of the wafer process of step 4 of the flowchart shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exposure light source 2 Reticle 3 Reticle reference plate 4 Reticle stage 5 Projection optical system 6 Light projection optical system 7 Detection optical system 8 Wafer 9 Stage reference plate 10 Wafer stage 20 TTR observation optical system 21 Fiber 22 Half mirror 23 Objective lens 24 Mirror 25 Image sensor 30 Light source control system 40 Reticle stage control system 50 Projection optical system control system 60 Wafer stage control system 70 Exposure apparatus control system 70a Storage means 70b Correction measurement control means 100 Off-axis observation optical system 101a, 101b, 101c Laser interferometer 102,103 Laser interferometer

Claims (7)

A substrate stage that holds and moves the substrate;
A projection optical system that projects light from an original onto a substrate held by the substrate stage;
First measurement for measuring light through the projection optical system and a reference plane arranged on the substrate stage in order to measure the position of the image plane of the projection optical system in the direction of the optical axis of the projection optical system Means,
A second measuring means for measuring a position of the target surface arranged on the substrate stage in the direction of the optical axis;
Have
Calibration of the second measuring unit based on the position of the image plane measured using the first measuring unit and the position of the reference plane as the target plane measured by the second measuring unit And measuring the position of the surface of the substrate as the target surface arranged on the substrate stage by the calibrated second measuring means, and based on the measured position of the surface, the substrate stage An exposure apparatus that exposes the substrate held on the positioned substrate stage through the original plate,
The post-calibration output of the first measurement means in a state where the reference plane is positioned by the substrate stage, and the post-calibration of the second measurement means using the reference plane in the state as the target plane Calculating means for calculating a relative change amount after the calibration between the output of the first measuring means and the output of the second measuring means based on the output;
An exposure apparatus comprising: The reference plane is positioned based on the output of one of the first measuring means and the second measuring means, and the other of the first measuring means and the second measuring means is positioned in the positioned state. Output
The calculating means includes
Storage means for storing the relationship between the output of the first measurement means and the output of the second measurement means when the calibration is performed, and the one output, the other output, Calculating the relative change amount based on the relationship stored in the storage means;
The exposure apparatus according to claim 1, wherein: A substrate stage that holds and moves the substrate;
A projection optical system that projects light from an original onto a substrate held by the substrate stage;
First measurement means for measuring a position of a reference mark disposed on the substrate stage via the projection optical system;
A second measuring means for measuring the position of the target mark placed on the substrate stage without passing through the projection optical system;
Have
The second measuring means based on the position of the reference mark measured using the first measuring means and the position of the reference mark as the target mark measured using the second measuring means. The position of the alignment mark as the target mark placed on the substrate held on the substrate stage is measured by the second measuring means subjected to the calibration, and the position of the measured alignment mark An exposure apparatus that positions the substrate stage based on the substrate stage and exposes the substrate held by the positioned substrate stage through the original plate,
The post-calibration output of the first measurement means in a state where the reference mark is positioned by the substrate stage, and the post-calibration of the second measurement means using the reference mark in the state as the target mark Calculating means for calculating a relative change amount after the calibration between the output of the first measuring means and the output of the second measuring means based on the output;
An exposure apparatus comprising: The reference plane is positioned based on the output of one of the first measuring means and the second measuring means, and the other of the first measuring means and the second measuring means is positioned in the positioned state. Output
The calculating means includes
Storage means for storing the relationship between the output of the first measurement means and the output of the second measurement means when the calibration is performed, and the one output, the other output, Calculating the relative change amount based on the relationship stored in the storage means;
The exposure apparatus according to claim 3, wherein: Notification means for performing notification corresponding to the calculated relative change amount exceeding an allowable amount;
The exposure apparatus according to claim 1, wherein the exposure apparatus comprises: Performing the calibration when the calculated relative change exceeds an allowable amount;
5. An exposure apparatus according to claim 1, wherein A step of exposing the substrate using the exposure apparatus according to claim 1;
Developing the exposed substrate;
A device manufacturing method comprising:

Images