JPH09266151A - Aligner and aligning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent degradation of total precision in alignment of a mask pattern image due to thermal expansion of a mask. SOLUTION: When a mask (reticle R) is irradiated by exposure light IL in a predetermined wavelength area, and a pattern image on the mask is formed on a substrate coated with a photosensitive agent by repeating movement of a wafer stage 12, calculation means 22 calculates information on a saturation point of thermal expansion of the mask by absorption of the exposure light IL. Before exposure with respect to the substrate is started, the mask is expanded based on the information calculated by the calculation means 22.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an exposure apparatus and an exposure method, and more particularly to an exposure apparatus and an exposure method used in a lithography process for manufacturing an IC, a liquid crystal substrate, a thin film magnetic head, and the like. It is.

[0002]

2. Description of the Related Art Conventionally, in an exposure apparatus used for manufacturing an IC, a liquid crystal substrate, or the like, an image forming state (for example, magnification, focal position) caused by atmospheric pressure fluctuation or absorption of exposure light by a projection optical system. Is provided. As such a correction mechanism, for example, a method of moving each lens element forming the projection optical system in the optical axis direction or tilting it with respect to a plane orthogonal to the optical axis, or a method of forming an airtight space between lens elements A method for adjusting pressure (Japanese Patent Laid-Open No. 60-78454) has been proposed.

However, since the exposure light also passes through the mask, the mask absorbs the exposure light and thermally expands, thereby forming an image in the projection optical system (magnification and image formation position of the projected image of the mask pattern). However, there is a problem in that In order to improve such a problem, for example, the thermal deformation amount of the mask due to absorption of illumination light (exposure light) is calculated,
The change in the image formation state is predicted based on the calculation result. A technique has been proposed that attempts to minimize the influence of fluctuations in the image formation state using this prediction result (see Japanese Patent Laid-Open No. 4-192317).

[0004]

However, the technique described in Japanese Patent Laid-Open No. 4-192317 mentioned above is
The thermal deformation amount (expansion amount) of the mask is calculated, and a change in the image formation state is predicted from the thermal deformation amount by a formulation based on optical calculation. Therefore, there has been a problem that accurate correction cannot be sufficiently performed due to a prediction error and complicated and complicated calculations are required.

Further, due to the thermal expansion of the mask, the distance management between the position of the image of the mask pattern and the position of the detection position of the sensor provided outside the optical axis of the projection lens (hereinafter,
It is called a baseline check. ) Was out of order.
As a result, when a plurality of images of other mask patterns are superposed on the mask pattern formed on the wafer, there is a problem that the overall superposition accuracy is deteriorated.

The present invention has been made in view of the above problems, and changes in the image forming state of the projection optical system (magnification) without complicated and complicated calculation for obtaining the change in the image forming state. It is an object of the present invention to provide an exposure apparatus and an exposure method that corrects the above) and prevents the baseline check from being misaligned.

[0007]

As in the prior art, the expansion of the mask is saturated without taking into consideration the deformation process due to the thermal deformation (for example, expansion. The expansion will be described below as an example) of the mask. Use a mask that has reached the state. That is, since the mask reaches the saturation point of thermal expansion, the mask does not expand or contract, and always maintains a stable shape. As a result, the above problem caused by the thermal expansion of the mask can be solved. The present invention has the following configuration based on this solution principle.

In the exposure apparatus according to the first invention (claim 1), the mask (reticle R) is illuminated with the exposure light IL in a predetermined wavelength range, and the image of the pattern on the mask is exposed through the projection optical system. Wafer stage 12 on the coated substrate
In the exposure apparatus which repeatedly forms the movement of the exposure light, a calculation unit 22 for calculating information about a saturation point of thermal expansion of the mask due to absorption of the exposure light IL is provided, and the calculation unit 22 calculates the information before starting the exposure on the substrate. The mask is inflated based on the calculated information.

The exposure apparatus according to the second invention (claim 2) is configured to expand the mask by irradiating the exposure light IL based on the information calculated by the calculating means 22. An exposure apparatus according to a third aspect of the present invention (claim 3) is the exposure apparatus according to the first aspect of the present invention, and has a heater HT for heating the mask based on the information calculated by the calculation means 22.

An exposure apparatus according to a fourth invention (claim 4) is the exposure apparatus according to the first invention, further comprising an exposure light I.
A configuration is provided in which a control unit that controls passage and light shielding of L is included, and the information is calculated based on the passage time and the light shielding time of the exposure light IL controlled by the control unit. An exposure apparatus according to a fifth aspect of the present invention (claim 5) is the exposure apparatus according to the first and second aspects of the present invention, further comprising a correction unit 18 for correcting the magnification of the image of the pattern on the mask. The optical path length between the mask and the substrate is changed in a state where the temperature reaches the saturation point of thermal expansion.

An exposure method according to a sixth aspect of the present invention (claim 6) illuminates a mask (reticle R) with exposure light IL in a predetermined wavelength range, and an image of the pattern on the mask is sensitized through a projection optical system. In the exposure method of repeatedly moving the stage 12 on the substrate coated with
Calculating information about a saturation point of thermal expansion of the mask due to absorption of L; expanding the mask based on the information calculated by the calculating means before starting exposure on the substrate; And a step of exposing the plate to light.

An exposure apparatus according to the seventh invention (claim 7) is
In the exposure method of the sixth invention, after the step of expanding the mask and before the step of exposing, the position of the image of the mask and the position of the detection position of the detection optical system provided outside the optical axis of the projection optical system. It is configured to include a step of managing the relationship.

[0013]

1 is a diagram showing a schematic configuration of an exposure apparatus as an exposure apparatus according to a first embodiment of the present invention. This exposure apparatus is used in the plane (X
Wafer stage 12 that moves two-dimensionally (in the Y plane)
And an image of a pattern of a reticle R as a mask arranged above the projection lens PL, and a wafer W as a photosensitive substrate.
A projection lens PL as a projection optical system for projecting the light upward, an exposure light source 14 for emitting the exposure light IL, an illumination optical system for irradiating the reticle R with the exposure light IL, and a projected image of a pattern of the reticle R. A magnification adjustment mechanism 18 for adjusting the magnification,
A main control system 22 for controlling these, a wafer alignment system 100 for performing wafer alignment and baseline check, and a TTR alignment system 101 for performing reticle alignment and baseline check.
And so on. The projection lens PL is arranged so that its optical axis AX is orthogonal to the moving direction of the wafer stage 12.

The wafer stage 12 is provided with a stage drive unit 20 including a motor (not shown). The movement of the wafer stage 12 depends on the light wave interferometer 27.
Is detected by measuring the movement of the movable mirror 26.
Although not shown, the light wave interference system 27 includes the stage X,
Two are provided on the X and Y coordinate axes in order to measure the movement on the Y coordinate axis. The main control system 22 controls the drive of the stage drive unit 20 based on the output of the light wave interferometer 26. This allows the wafer stage 12 to move two-dimensionally on the X and Y coordinate axes. A wafer holder 24 is provided on the wafer stage 12, and the wafer W is held on the wafer holder 24 by vacuum suction. In addition, the dummy exposure area 25 is placed on the wafer stage.
(Details will be described later) and a reference mark FM are provided.

As the projection lens PL, a bilateral telecentric projection lens is used in this embodiment. The projection lens PL is actually configured to include a plurality of lens elements (all are not shown) arranged along the optical axis AX direction (Z-axis direction). Reticle R
Are X, in a plane orthogonal to the optical axis AX of the projection lens PL.
It is held on a reticle stage 28 that moves slightly in Y and θ. Note that the pattern surface of reticle R is conjugate with the surface of wafer W with respect to projection lens PL.

The light source 14 sensitizes a resist as a photosensitizer applied on the wafer W, and therefore, for example, an ultrahigh pressure mercury lamp, an excimer laser (KrF, ArF), YA.
It is composed of a G laser or the like, and generates exposure light IL such as g-line, i-line, excimer light (wavelength 248 nm: KrF, 193 nm: ArF), harmonic of YAG laser (wavelength 200 nm or less). In the present embodiment, the light source 14 is described as i-line.

The irradiation optical system for illuminating the reticle R with the exposure light IL is a mirror 30 that reflects the exposure light IL emitted from the light source 14 and bends the exposure light IL horizontally, and the exposure light IL reflected by the mirror 30 advances. Optical integrators (fly-eye lenses) arranged sequentially in the direction
A fly-eye optical system 32 and a relay optical system 34 including
The dichroic mirror 36 includes a dichroic mirror 36 obliquely arranged at an angle of about 45 degrees above the reticle R, and a main condenser lens 38 disposed between the dichroic mirror 36 and the reticle R. Light source 14 and mirror 30
Between the shutter 40 and the shutter 40 for opening and closing the optical path of the exposure light IL.
The shutter 40 is driven by a shutter control circuit 44 via a shutter driving unit 42. An illumination system stop 46 is arranged on the exit surface of the fly-eye optical system 32 (Fourier transform surface with respect to the reticle R). The exit surface of the fly-eye lens optical system 32 is arranged conjugate with the pupil plane of the projection lens PL.

A blind 52 is provided in the relay optical system 34 in order to make the irradiation area of the exposure light IL on the reticle R variable. This blind 52
It is arranged conjugate with the pattern surface of reticle R. The blind 52 is driven by the blind drive unit 54, and the irradiation area on the reticle R is set by the blind drive unit 54 and the blind 52.

The magnification adjusting mechanism 18 corrects the image forming characteristics of the photographing optical system, for example, the image forming magnification of the projected image of the pattern of the reticle R and the optimum image forming plane position (focal point position). In the present embodiment, a mechanism that increases or decreases the pressure in the airtight space between specific lens elements constituting the projection lens PL is used as the magnification adjusting mechanism 18. As the magnification conversion mechanism, for example, one that drives, tilts, or rotates some lens elements that configure the projection lens PL in the optical axis AX direction by a driving element such as a piezoelectric element or a magnetostrictive element is used. May be. The magnification adjustment mechanism 18 is controlled by a magnification correction controller 64.

The memory 21 stores data (the coefficient of thermal expansion of the reticle, the reticle R) necessary for calculating the saturation point of the thermal expansion of the reticle R that expands by absorbing the exposure light.
The irradiation area above, the shutter open / close ratio, etc.) are stored. Further, a mathematical expression for calculating the thermal expansion saturation point is also stored. The main control system 22 controls the shutter control circuit 44, the magnification correction controller 64, and the wafer stage 12 described above. Further, C included in the main control system 22
The thermal expansion saturation point of the reticle R is also calculated by a calculation means such as PU. The calculation means for calculating the thermal expansion saturation point may be provided outside the main control system 22.

Wafer alignment system 100 and TTR
The alignment system 101 is used for alignment and baseline check. In this embodiment, as shown in FIG. 1, the TTR alignment method will be described as an example. The TTR alignment system 101 is provided above the reticle R, and the reticle mark R around the circuit pattern area of the reticle R is used for the baseline check.
M and fiducial mark FM provided on the wafer stage 12
It is a detection optical system for simultaneously detecting and. The wafer alignment system 100 forms a so-called off-axis system provided around the projection lens PL. The wafer alignment system 100 is a detection optical system for detecting the reference mark FM and the alignment mark 111 during a baseline check and wafer alignment. The wafer alignment system 100 and T
The TR alignment system 101 is also provided in the direction perpendicular to the paper surface in FIG. 1, and can perform two-dimensional alignment or baseline check of the reticle R and the wafer W.

By the way, the TTR alignment system 101
Detects the reticle mark RM and the reference mark FM with the light beam supplied from the light guide 120. The light guide 120 supplies illumination light having the same wavelength as the exposure light IL, and irradiates the reticle mark RM and the reference mark FM. For example, the reticle R and the reference mark FM are irradiated with the exposure light IL from the light source 14 through the light guide 120. Further, the wafer alignment system 100 detects the reference mark FM and the alignment mark 111 by the light flux supplied by the light guide 121. The light guide 121 does not need to supply the same wavelength as the exposure light IL, and supplies illumination light from a light source such as a halogen lamp.

Further, the wafer alignment system 100 provided around the projection lens PL (outside the projection visual field) internally detects the alignment mark 111 or the reference mark FM on the wafer W, and serves as a reference index mark. TM
Are provided on the glass plate and are arranged substantially conjugate with the projection image plane (the wafer surface or the plane of the reference mark FM). The optical axis of the wafer alignment system 100 is parallel to the optical axis AX of the projection lens PL on the projection plane image side.

Hereinafter, the exposure apparatus having the above configuration calculates the saturation point of thermal expansion of the reticle R, and expands the reticle R with the amount of thermal energy required to reach the calculated saturation point of thermal expansion. A process step of starting exposure of the pattern of the reticle R onto the wafer W after performing baseline check, alignment, and magnification correction using the expanded reticle R will be described.

In the above process of exposing the pattern of the reticle R onto the wafer W, the saturation point of the thermal expansion of the reticle R is calculated prior to the exposure of the actual exposure shot of the wafer W. First, the calculation method will be described. The exposure apparatus in the present embodiment is a so-called stepping-and-repeat method in which exposure is repeated while sequentially moving the wafer stage 12 on which the wafer W is placed in the X and Y directions, and a pattern of the reticle R is formed on one wafer. Is an apparatus for sequentially forming (exposure) a plurality of images. At this time, the shutter 40 repeatedly passes the exposure light IL (the shutter is open) and shields the light (shutter is closed) in synchronization with the movement of the wafer stage 12. FIG. 2 is a diagram showing the state of thermal expansion of the reticle at this time. In FIG. 2, to is the time when the shutter is open, tc is the time when the shutter is closed, and tw is the time when one wafer is exposed.
tp represents the time when the wafer is exchanged, and t represents the time when the reticle reaches the thermal expansion saturation point. Also, reticle R
Is the exposure power P (W / cm ² ), the irradiation area S (cm ² ) on the reticle R, and the thermal expansion coefficient K (μm /
Expands depending on W). The irradiation area S is set by the blind drive unit 54 driving the blind 52 as described above. The thermal expansion coefficient K of the reticle is determined by the distribution density of the reticle pattern, the type of member of the blind 52, and the like. Note that these are constants set before exposure. From the above, the thermal expansion saturation point M
1 can be expressed by the following formula. The thermal expansion saturation point is the expansion change distance per unit distance from the normal state until the thermal expansion reaches the saturated state, and the unit is expressed in μm. M1 = K × P × S × to / (t + tc) (1) Further, the shutter is always open and the exposure light IL
The thermal expansion saturation point M can be expressed by the following equation when is continuously irradiated with. M = K × P × S ' × 1 × (1-exp (- (t / T))) ... (2) where, S' (cm ²⁾ is irradiated area at this time, T (se
c) represents the thermal expansion time constant of the reticle. It should be noted that the thermal expansion time constant T is a predetermined constant, like the parameters such as the thermal expansion coefficient K of the reticle.

Next, the shutter is kept open until the thermal expansion saturation point M1 of the reticle R, which undergoes thermal expansion while repeatedly opening and closing the shutter, and the exposure light IL is continuously irradiated to expand the reticle. Time t
Ask for. This time t is the time when M1 in the equation (1) becomes equal to M in the equation (2), and is as follows. t = -T * In (1-S / S '* to / (to-tc)) (3) That is, when the exposure light is irradiated at the time t calculated by the equation (3), the reticle R is thermally expanded. The necessary amount of heat energy to reach the saturation point will be obtained.

As described above, the reticle R is continuously irradiated with the exposure light IL until the time t. As a result, the reticle R reaches the thermal expansion saturation point before the exposure is started. It should be noted that the exposure light IL irradiated onto the reticle R until reaching the thermal expansion saturation point is the dummy exposure area 25.
Is irradiated. This dummy exposure area 25 is a reticle R.
Through the wafer holder 24 on the wafer stage 12
Is a region provided at a position different from. This allows
It is possible to prevent the exposure light IL from adversely affecting the wafer holder 24 such as thermal expansion. Here, as a method of preventing adverse effects due to thermal expansion of the wafer holder 24 other than irradiation of the dummy exposure area 25, the reticle stage 2 is used.
It is conceivable that the wafer holder 24 is prevented from being irradiated by moving the reticle R 8 and irradiating the moved reticle R with the exposure light IL. In this case, the movable mirror (not shown) is inserted into the optical path of the exposure light IL by a predetermined drive system (not shown) only when the reticle R is irradiated and expanded. Then, the movable mirror reflects the exposure light IL, and the exposure light IL is applied to the reticle stage 28 that has been moved and retracted. Further, as another method, a method of retracting the wafer stage 12 on which the wafer holder 24 is placed from the irradiation position of the exposure light IL can be considered.

Although the reticle R is thermally expanded by irradiating the reticle R with the exposure light IL in the present embodiment, the present invention is not limited to this. It is also possible to use a heater HT such as a heater capable of giving the reticle R the thermal energy necessary for the reticle R to reach the thermal expansion saturation point. In this case, the heater HT may be provided on the side surface of the reticle R as shown in FIG. 1. For example, the condenser lens 38 may be provided only when heat energy is applied to the reticle R.
And a reticle R are inserted by a drive system (not shown),
The reticle R may be heated until it reaches the thermal expansion saturation point, and then retracted from the optical path of the exposure light IL. Also,
The heater HT may heat the reticle R via the reticle holder 28. As a result, the wafer holder 24 is not irradiated with the exposure light, so that the wafer holder 24
It is possible to prevent adverse effects due to thermal expansion and the like.

By the way, since the reticle R expands by absorbing the heat of the exposure light IL, the magnification changes before and after the expansion. Therefore, it is necessary to correct this change in magnification. Hereinafter, a method of magnification correction will be described. The CPU in the main control system 22 calculates in advance how much the magnification has changed from the normal state in which the reticle R does not absorb heat to the thermal expansion saturation point (hereinafter referred to as magnification change), and the memory 21. To memorize. This change in magnification can be calculated from equation (1). The main control system 22 reads the magnification change stored in the memory 21, and controls the magnification adjusting mechanism 18 via the magnification correction controller 64 based on the read value. The magnification adjusting mechanism 18 is controlled by the magnification correction controller 64 to increase or decrease the pressure in the airtight space between the specific lens elements constituting the projection lens PL, and to correct the magnification so that the reticle R has the same magnification as before the expansion. In this way, the magnification change corresponding to the expansion of the reticle R to reach the thermal expansion saturation point is corrected. This allows
A change in magnification due to thermal expansion of the reticle R can be prevented, and exposure can always be performed at a constant magnification. In this embodiment, the optical path length between the reticle R and the wafer W is changed by increasing or decreasing the pressure in the airtight space between the lens elements. It is also possible to change the optical path length by moving a part of the optical path in a direction parallel to the optical axis. As described above, moving the lens element to change the optical path length to perform magnification correction is disclosed in detail in Japanese Patent Laid-Open No. 4-192317.

Next, after the magnification correction is performed as described above, a baseline check is performed before starting exposure using the reticle R that has reached the thermal expansion saturation point. The reticle R is held by the reticle stage 28, and the center CC of the reticle R is projected onto the projection lens PL.
Is moved to match the optical axis of. On the other hand, as described above, the reference mark FM is provided on the wafer stage 12, and the wafer stage 12 is positioned so that the reference mark FM comes to a predetermined position within the projection visual field of the projection lens PL. The TTR alignment system 101 provided above the reticle R simultaneously detects and aligns the reticle mark RM provided on the reticle R and the reference mark FM provided on the wafer W. The position of the wafer stage 12 at this time is measured by the light wave interferometer 27.

Next, the wafer stage 12 is set so that the reference mark FM is detected by the wafer alignment system 100.
Is moved. Then, the position of the wafer stage 12 when the reference mark FM is aligned with the index mark TM (that is, when the reference mark FM is aligned with the detection center of the wafer alignment system 100) is measured by the light wave interference system 27. To do.

By the way, the baseline amount BL is aligned with the position P on the stage 12 when the reticle mark RM and the reference mark FM are aligned, and the index mark TM and the reference mark FM, as shown in FIG. The position Q on the stage 12 at that time is measured by the light wave interferometer 27 or the like, and the difference (P−Q) is calculated. The baseline amount BL is a reference amount when the marks on the wafer are later aligned by the wafer alignment system 100 and sent directly below the projection lens PL, that is, the center of the shot and the center of the projected image of the reticle R. It serves as a reference amount for matching (alignment). Therefore, the alignment mark 111 becomes the index mark T
When the position of the wafer stage 12 when it matches M is X3, in order to match the center of the shot and the center CC of the reticle R, the wafer stage 12 is moved to a position where the coordinate X3 is corrected by the baseline amount BL. You can do it.

Although the alignment method using the baseline has been described only in the one-dimensional direction, it is actually necessary to consider it in two dimensions. As a result, after the mark position on the wafer W is detected by using the wafer alignment system 100, the pattern of the reticle R can be accurately superimposed on the shot area on the wafer W immediately by feeding the wafer stage 12 by a fixed amount. Can be exposed.

As described above, the baseline check is performed before the exposure is started by using the reticle R which has reached the thermal expansion saturation point. As a result, the reticle R absorbs the exposure light IL and expands, and the baseline management is not disturbed, so that highly accurate exposure can be performed. After the baseline check is completed, wafer alignment is performed. In the present embodiment, among shot areas on wafer W, several shots (for example, 5 to 10 shots) are selected as sample shots, and for each sample shot, an alignment mark formed around the sample shot area is formed. Measure the position of. Then, using the measured mark position information and the mark design value, the wafer stage 12 is moved under the projection lens based on the shot arrangement coordinates calculated by the statistical calculation method to perform alignment. And Such an alignment method (hereinafter referred to as an EGA method)
Are disclosed in detail, for example, in JP-A-61-44429. The measurement of the wafer mark position in this embodiment uses the wafer alignment system 100 provided around the projection lens PL. The wafer alignment system 100 has TMX1, TMX2 and TMX as index marks TM having a multi-line pattern as shown in FIG.
MY1 and TMY2 are provided. Further, FIG. 3A shows a sample shot SA, and sample shot SA1
Alignment marks 111 and 112 having, for example, a multi-line pattern are formed in the peripheral portion of the.

Explaining with a specific example, first, as shown in FIG. 3B, the alignment mark 111 formed in the peripheral portion of the sample shot SA1 on the wafer W is detected by the wafer alignment system 100. The wafer stage 12 is positioned so that the index mark is sandwiched between TMX1 and TMX2 in the area. Then, the main control system 22 reads the coordinate position of the positioned wafer stage 12 from the light wave interference system 27. A CCD camera is provided in the wafer alignment system 100, and CC
The D camera simultaneously captures an image of the alignment mark 111 and an image of the index mark TM (TMX1, TMX2), and outputs an image signal corresponding to the alignment mark 111 and the index mark FM. Further, the main control system 22 processes the image signal from the CCD camera to detect the deviation amount between the center of the index plate and the center point of the alignment mark 111, and the deviation amount and the coordinates of the wafer stage 12 at this time. The coordinates of the alignment mark 111 are calculated based on the position. Similarly, the coordinate position of the alignment mark 112 in the Y direction is measured using the index marks TMY1 and TMY2. Then, the coordinate position of the alignment mark is similarly measured for each sample shot. Based on these measured values, the main control system 22 obtains shot arrangement coordinates on the wafer W obtained by the EGA method, and moves the wafer stage 12 based on the arrangement coordinates and the baseline amount BL to execute alignment. To do.

By the way, in the above description, the reticle R
The expansion has been described on the assumption that the expansion is isotropic from the center of the reticle R. If the reticle R expands anisotropically and non-uniformly, the center of the reticle R in a state where the thermal expansion saturation point is reached is measured and detected using a measuring instrument such as a ruler, or Is detected by image processing after capturing the video signal. Then, the reference value of the center of the measured reticle R (the reticle mark R obtained in advance
Alignment may be performed by adding an amount obtained by multiplying a deviation amount from the distance between M and the center of the reticle) by a magnification to the baseline amount BL as an offset. As a result, it is possible to prevent deterioration of the overall overlay accuracy, as in the case where the reticle R expands isotropically.

[0037]

According to the present invention, the baseline check and the magnification correction are performed using the reticle expanded to the thermal expansion saturation point. As a result, it is possible to prevent deterioration of accuracy due to thermal expansion of the reticle, prevent deterioration of accuracy due to a prediction error, which is a conventional problem, and eliminate the need for complicated and complicated calculations. can do.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a state of thermal expansion of a reticle.

FIG. 3 is a diagram showing an alignment mark and an index mark TM.

[Description of Signs of Main Parts]

 12 wafer stage 14 light source 18 magnification adjusting mechanism 20 stage drive unit 21 memory 22 main control system 24 wafer holder 25 dummy exposure area 26 moving mirror 27 light wave interferometer 28 reticle stage 30 mirror 32 fly eye optical system 34 relay optical system 36 dichroic mirror 38 Main Condenser Lens 40 Shutter 42 Shutter Drive Unit 44 Shutter Control Circuit 46 Illumination System Aperture 52 Blind 54 Reticle Blind Drive Unit 64 Magnification Correction Controller 100 Wafer Alignment System 101 TTR Alignment System 102 Dummy Exposure Area 111, 112 Alignment Mark 120 Light Guide 121 Light guide PL Projection lens R Reticle W Wafer AX Optical axis FM Reference mark RM Reticle mark HT Heating TM reference mark

Claims (7)

[Claims] 1. An exposure apparatus which illuminates a mask with exposure light in a predetermined wavelength range and forms an image of the pattern on the mask on a substrate coated with a photosensitive agent through a projection optical system by repeatedly moving a stage. In, comprising a calculation means for calculating information about a saturation point of thermal expansion of the mask due to absorption of the exposure light, before starting exposure on the substrate, based on the information calculated by the calculation means An exposure apparatus characterized by expanding a mask. 2. The exposure apparatus according to claim 1, wherein the mask is expanded by irradiating the exposure light based on the information calculated by the calculating means. 3. The exposure apparatus according to claim 1, further comprising a heater that heats the mask based on the information calculated by the calculation means. 4. The exposure apparatus according to claim 1, further comprising a control unit that controls passage and blocking of the exposure light, wherein the calculation unit controls the passage time of the exposure light controlled by the control unit. And an exposure apparatus, wherein the information is calculated based on a light blocking time. 5. The exposure apparatus according to claim 1, further comprising a correction means for correcting the magnification of the image of the pattern on the mask, wherein the correction means has reached the saturation point of thermal expansion of the mask. An exposure apparatus, wherein an optical path length between the mask and the substrate is changed in a state. 6. An exposure method in which a mask is illuminated with exposure light in a predetermined wavelength range, and an image of the pattern on the mask is formed through a projection optical system on a substrate coated with a photosensitive agent by repeatedly moving a stage. In the step of calculating information about a saturation point of thermal expansion of the mask due to absorption of the exposure light, before starting exposure on the substrate, the mask based on the information calculated by the calculating means. An exposure method comprising the steps of expanding and exposing the substrate plate. 7. The exposure method according to claim 6, wherein after the step of expanding the mask and before the step of exposing, it is provided outside the optical axis of the image position of the mask and the projection optical system. An exposure method comprising a step of managing a positional relationship between a detection optical system and a detection position.