JP2000003871A - Exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expose a wafer by a slit scanning exposure method, while focusing and levelling are conducted accurately without lowering the through put. SOLUTION: The pattern of a reticle 3, which is limited by a reticle blind 5, is projected onto an exposure region 11 through a projection optical system 9. A wafer 10 and the reticle 3 are scanned relative to the exposure region 11, synchronously with each other to project the entire patterns of the reticle 3 onto the wafer 10. The heights of a plurality of positions of an exposed part on the wafer 10 are estimated beforehand by a multipoint focus position detector 19, and the height and the inclination of the exposed part which are set by a Z-levelling stage 12 when the exposed part reaches the exposure region 11 are controlled, in accordance with the heights and the inclinations calculated as the results of estimation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of illuminating a rectangular or arcuate illumination area with, for example, exposure light and scanning the mask and photosensitive substrate in synchronism with the illumination area. The present invention relates to an exposure method suitable for being applied to a so-called slit scan exposure type exposure apparatus that exposes the light onto a photosensitive substrate.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor device, a liquid crystal display device, a thin film magnetic head, or the like is manufactured by using photolithography technology, a photomask or a reticle (hereinafter, referred to as a "reticle") has been used.
A projection exposure apparatus that exposes a pattern of a “reticle” to a photosensitive substrate such as a wafer or a glass plate coated with a photoresist or the like via a projection optical system is used. Recently, one chip pattern or the like of a semiconductor element has been increasing in size, and a projection exposure apparatus is required to have a large area for exposing a pattern having a larger area on a reticle onto a photosensitive substrate.

Further, as the pattern of a semiconductor element or the like becomes finer, it is required to improve the resolution of the projection optical system. However, in order to improve the resolution of the projection optical system, the projection optical system must be improved. However, there is a problem that the exposure field cannot be made too large. In particular, when a catadioptric system is used as the projection optical system, the shape of the aberration-free exposure field may be an arc-shaped region.

In order to increase the area of the pattern to be transferred and to limit the exposure field of the projection optical system, for example, a rectangular, arcuate or hexagonal illumination area (this is called a "slit illumination area"). A so-called slit scan exposure type projection exposure apparatus for exposing a pattern having a larger area than the slit-shaped illumination area on the reticle onto the photosensitive substrate by synchronously scanning the reticle and the photosensitive substrate has been developed. I have. Generally, in a projection exposure apparatus, it is necessary to perform exposure in a state where the exposure surface of the photosensitive substrate is aligned with the image plane (best image formation plane) of the projection optical system.
Even in the projection exposure apparatus of the slit scan exposure method,
An auto-focus mechanism that adjusts the height (focus position) of the reference point of the exposure surface of the photosensitive substrate in the focus direction to the image surface, and an auto-focus mechanism that adjusts the average exposure surface of the photosensitive substrate parallel to the image surface And a leveling mechanism.

In a conventional auto-focus mechanism, the height of a photosensitive substrate at or near the center of an exposure field of a projection optical system is detected by a focus position detection means, and the height is used as the height of the image plane of the projection optical system. Sa (best focus position)
The height of the substrate stage on which the photosensitive substrate is mounted is controlled so as to adjust the height. Similarly, the conventional auto-leveling mechanism detects the average inclination of the exposure surface of the photosensitive substrate in the exposure field of the projection optical system by the inclination angle detection means, and adjusts the inclination to the inclination of the image plane of the projection optical system. That is, the inclination of the substrate stage is controlled.

[0006]

In the conventional auto focus mechanism, the detection point by the focus position detection means is set at or near the exposure center in the exposure field of the projection optical system. Due to the influence of the phase delay caused by the signal processing time, there is a disadvantage that the focusing of the photosensitive substrate (focusing) becomes inaccurate. That is, in the case of the slit scan exposure method, since the photosensitive substrate is scanned with respect to the exposure field of the projection optical system, based on the focus position of a certain exposure area detected at the exposure center in the exposure field. However, even if the height of the substrate stage is adjusted after a predetermined signal processing time, it is not always possible to perform accurate focusing because another exposure area is included in the exposure field. .

To prevent this, it is conceivable to reduce the feed speed of the substrate stage. However, if the feed speed of the substrate stage is reduced, there is a disadvantage that the exposure time becomes longer and the throughput decreases. Similarly, in the conventional auto-leveling mechanism, since the detection surface of the tilt angle detecting means is set in the exposure field of the projection optical system, it is affected by the phase delay caused by the signal processing time of the tilt angle detecting means. In addition, there is a disadvantage that leveling of the photosensitive substrate becomes inaccurate.

The present invention has been made in view of the above circumstances, and provides a projection exposure apparatus of a slit scan exposure system capable of performing exposure in a state where focusing is accurately performed without reducing throughput. Aim. Still another object of the present invention is to provide an exposure method capable of performing exposure in a state where leveling is performed accurately without lowering throughput in a projection exposure apparatus of a slit scan exposure system.

[0009]

A first exposure method according to the present invention illuminates a slit-shaped illumination area with exposure light, as shown in FIGS. 1 to 3, for example. The mask (3) on which the pattern for transfer is formed is scanned, and the slit-like illumination area is synchronized with the mask (3) with respect to the slit-like exposure area (11) projected by the projection optical system (9). And substrate stage (12, 13)
In the method of exposing the pattern of the mask (3) on the photosensitive substrate (10) by scanning the upper photosensitive substrate (10), after starting the synchronized scanning of the mask (3) and the photosensitive substrate (10) The height of the exposure area (30) on the photosensitive substrate (10) separated by a predetermined distance from the slit-like exposure area (11) in the direction opposite to the scanning direction and the image plane of the projection optical system (9). A substrate stage (12, 13) on which a photosensitive substrate (10) is placed while detecting a difference from the height.
When the exposure area (30) reaches the slit-shaped exposure area (11), the height set on the substrate stage (12, 13) is detected. The height of the region to be exposed (30) is adjusted to the height of the image plane of the projection optical system (9) by setting the height to the sum of the height and the detected difference. is there.

In a second exposure method of the present invention, as shown in FIGS. 1 to 3, for example, a slit-shaped illumination area is illuminated with exposure light, and a transfer pattern is applied to the slit-shaped illumination area. Scans the mask (3) on which is formed,
A mask (3) is applied to the slit-shaped exposure area (11) projected by the projection optical system (9) on the slit-shaped illumination area.
Scanning the photosensitive substrate (10) on the substrate stage (12, 13) in synchronism with the exposure of the pattern of the mask (3) onto the photosensitive substrate (10). After starting the synchronized scanning of (10), the inclination of the exposed area (30) on the photosensitive substrate (10) separated from the slit-shaped exposure area (11) by a predetermined distance in a direction opposite to the scanning direction. The difference between the amount and the inclination amount of the image plane of the projection optical system (9) is detected, and the photosensitive substrate (1) is detected.
0) is detected on the substrate stage (12, 13) on which the substrate stage (12, 13) is mounted, and when the region to be exposed (30) reaches the inside of the slit-shaped exposure region (11), the substrate stage (12) is detected. By setting the tilt amount set in (12, 13) to the tilt amount obtained by adding the detected difference to the detected tilt amount, the area to be exposed (30) is set to the image plane of the projection optical system (9). It is designed to fit parallel to.

[0011]

According to the first exposure method of the present invention, the detection of the height of the photosensitive substrate (10) by the focus position detecting means is based on the phase delay due to the signal processing time of the focus position detecting means and the substrate stage (12). , 13) at a location separated from the exposure area (11) by a distance determined by the feed speed. Then, focusing based on the detected height of a certain exposure area (30) is performed.
Is performed when it moves to the exposure area (11), the phase lag of the focus position detecting means and the like can be offset by the time difference between them, and accurate focusing can be performed.

Similarly, according to the second exposure method, the detection of the tilt angle of the photosensitive substrate (10) by the tilt angle detecting means is based on the phase delay due to the signal processing time of the tilt angle detecting means and the substrate stage (12, 13). ) Is performed at a place separated from the exposure area (11) by a distance determined by the feed speed of (1). The leveling based on the detected tilt angle of a certain exposure area (30) is performed when the exposure area (30) moves to the exposure area (11). The phase delay of the detecting means and the like can be canceled, and leveling is performed accurately.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a slit scan exposure type projection exposure apparatus that uses a pulse oscillation type light source such as an excimer laser light source as a light source for exposure light. FIG. 1 shows a projection exposure apparatus of the present embodiment,
In FIG. 1, pulse light from a pulse laser light source 1 such as an excimer laser light source enters an illumination optical system 2. The pulse emission timing of the pulse laser light source 1 is arbitrarily set by a trigger control unit (not shown). The illumination optical system 2 includes a beam shaping optical system, a dimming optical system, an optical integrator, a field stop, a condenser lens system, and the like. The pulse light is converted by the illumination optical system 2 into pulse exposure light IL having substantially uniform illuminance. The pulse exposure light IL illuminates the reticle 3.

The reticle 3 is held on a reticle stage 4, and the reticle stage 4 is in an X direction (or -X direction) in a plane perpendicular to the optical axis of the projection optical system 9 and parallel to the plane of FIG.
In addition to scanning the reticle 3, the reticle 3 is positioned in the Y direction perpendicular to the X direction (the direction perpendicular to the plane of FIG. 1). A reticle blind 5 having a rectangular opening is arranged on the lower surface of reticle stage 4, and a rectangular illumination area is substantially set on reticle 3 by the opening of reticle blind 5. A movable mirror 6 is fixed on the reticle stage 4, and a laser beam from an external reticle-side interferometer 7 is reflected by the movable mirror 6, and the reticle-side interferometer 7 coordinates the reticle stage 4 in the X and Y directions. Is constantly measured, and the coordinate information S1 thus measured is supplied to a main control system 8 that controls the operation of the entire apparatus.

In the pattern drawn on the reticle 6,
An image of a portion limited by the opening of the reticle blind 5 is projected via a projection optical system 9 onto a wafer 10 coated with a photoresist as a photosensitive substrate. A region conjugate with respect to the projection optical system 5 and a region on the reticle 3 which is limited by the opening of the reticle blind 5 is a rectangular exposure region 11. Further, the wafer 10 is held on a Z-leveling stage 12,
Is mounted on the XY stage 13 on the wafer side. A Z leveling stage 12 for positioning the wafer 10 in the Z direction which is the optical axis direction of the projection optical system 9;
It is composed of a leveling stage and the like for tilting the exposure surface of the wafer 10 by a desired tilt angle. On the other hand, the wafer-side XY stage 13 scans the wafer 10 in the X direction.
It comprises a stage and a Y stage for positioning the wafer 10 in the Y direction.

A movable mirror 14 is mounted on a side surface of the Z leveling stage 12, and an external wafer-side interferometer 1 is provided.
5 is reflected by the moving mirror 14, and the X-ray of the wafer-side XY stage 13 is
The coordinates and the Y coordinate are constantly measured, and the coordinate information thus measured is supplied to the main control system 8. Further, the height (focus position) and inclination currently set in the Z-leveling stage 12 are detected by the Z-leveling stage position detecting device 17, and information on the detected height and inclination is sent to the arithmetic device 18. Supplied. The position detecting device 17 for the Z leveling stage is composed of, for example, a rotary encoder attached to the shaft of the drive motor or a potentiometer for directly detecting the height.

The multi-point focus position detecting devices 19 and 2 are provided on both side portions of the projection optical system 9 in the X direction.
0 is arranged. FIG. 2 shows the relationship between the detection areas of the multi-point focus position detection devices 19 and 20 and the rectangular exposure area 11. In FIG.
1a, centering on a position 21a at an interval D in the -X direction.
A detection area 21 having substantially the same size as the exposure area 11 is set. 5 on the side in the -X direction of this detection area 21
The first multi-point focus position in FIG. 1 is obliquely positioned on the four detection points 22A to 26A and the five detection points 22B to 26B on the side in the X direction, obliquely to the normal to the exposure surface of the wafer 10. A slit pattern image is projected from the detection device 19. As illumination light for projecting the slit pattern image, light in a wavelength region having low photosensitivity to the photoresist is used.

The reflected light from these ten slit pattern images returns to the multi-point focus position detecting device 19, and the multi-point focus position detecting device 19 outputs the re-formed images of the ten slit pattern images. Ten focus signals corresponding to the amount of lateral displacement from the reference position are generated. When the height of the wafer 10 in the Z direction changes,
Since the positions of the re-formed images of the zero slit pattern images are shifted laterally, the detection points 22A to 26A and 22B to 22B of the detection area 21 are respectively obtained from the ten focus signals.
The height (focus position) of the wafer 10 at 26B is detected.

Further, in FIG. 2, from a center 11a of the exposure region 11, a position 27a at a distance D in the X direction is set as a center.
A detection area 27 having a size substantially equal to that of the exposure area 11 is set. On ten detection points on the detection area 27, the detection area 27 is oblique to the normal to the exposure surface of the wafer 10.
Each of the second multi-point focus position detecting devices 20 shown in FIG.
, A slit pattern image is projected. These 10
The reflected light from each of the slit pattern images returns to the multipoint focus position detection device 20, and the multipoint focus position detection device 20
, And generates ten focus signals corresponding to the height.
For example, when the wafer 10 is scanned in the scanning direction RW along the X direction, the height information detected by the first multi-point focus position detection device 19 for the detection area 21 is used, and the wafer 10 is moved to -X Scanning direction RW 'along the direction
In the case where the scanning is performed, the height information detected by the second multipoint focus position detection device 20 for the detection area 27 is used.

Returning to FIG. 1, the information of the first set of ten focus signals and the information of the second set of ten focus signals S2 respectively output from the multipoint focus position detectors 19 and 20 are calculated by the arithmetic unit 18. Is supplied to The arithmetic unit 18 calculates the height and inclination (target height) to be set by the Z-leveling stage 12 with respect to the area to be exposed next in the exposure area 11 based on the information on the focus position read in advance as described later. And the target inclination), and informs the main control system 8 of information on the target height and the target inclination. The main control system 8 controls the operation of the Z leveling stage 12 via the wafer stage control device 16 according to this information. In addition, the main control system 8 scans the reticle stage 4 via a reticle stage control device (not shown) and synchronizes the scanning operation of the reticle side XY stage 13 with the wafer stage control device 16. Control.

In the present embodiment, when performing the exposure by the slit scan exposure method, for example, the wafer 10 is moved to the XY stage 13 in synchronization with the reticle 3 being scanned by the reticle stage 4 in the scanning direction RR (−X direction). Scanning direction RW
(X direction). In this case, assuming that the projection magnification of the projection optical system 9 is β and the scanning speed of the reticle 3 is VR, the scanning speed of the wafer 10 is β · VR. Thereby, all the patterns on the reticle 3 are sequentially exposed on the wafer 10. However, the scanning direction may be reversed. When the reticle 3 is scanned in the X direction, the wafer 10 is scanned in the −X direction in synchronization with the scanning.

The moving speed of the reticle stage 4 and the XY stage 13 on the wafer side during the slit scan exposure is determined by the amount of the pulse exposure light IL irradiated onto the reticle 3, the width of the opening of the reticle blind 5, and the application speed to the wafer 10. Determined by the sensitivity of the applied photoresist. That is, the speed of the reticle stage 4 is determined such that the photoresist on the reticle 3 is sufficiently exposed within the time required for the pattern on the reticle 3 to cross the opening of the reticle blind 5 by the movement of the reticle stage 4. Further, the center point 11a of the exposure area 11 and the center point 21a of the detection area 21 (or 27) shown in FIG.
(Or 27a) is equal to or longer than the distance that the wafer-side XY stage 13 moves during the delay time due to the signal processing time in the multipoint focus position detector 19 (or 20) and the arithmetic unit 18. Is set to the length.

Next, referring to the flowchart of FIG.
An example of the exposure operation of the present example will be described. In the exposure operation of this example, the following conditions are premised. The reference plane on which the surface of the portion to be exposed on the wafer 10 is aligned is the image plane (best imaging plane) of the projection optical system 9. The height and inclination set by the Z-leveling stage 12 are the same as the surface of a wafer having a good flatness (super flat wafer) held on the Z-leveling stage 12 via a wafer holder (not shown). Height and inclination. Such a surface determined by the height and the inclination set in the Z leveling stage 12 is called a “holder surface”.

The center of rotation at the time of leveling of the Z leveling stage 12 in FIG. 1 is the center 1 of the exposure area 11 in FIG.
1a. That is, the XY stage 13 on the wafer side
When the leveling is performed by the Z leveling stage 12 irrespective of the values of the X coordinate and the Y coordinate, the height (focus position) of the wafer 10 at the center 11 a of the exposure area 11 does not change.

Under such conditions, first, step 1 in FIG.
At 01, calibration of focus signals respectively corresponding to the ten detection points 22A to 26A and 22B to 26B in the detection area 21 and the ten detection points in the detection area 27 in FIG. For example, in order to calibrate focus signals corresponding to the detection points 22A to 26A and 22B to 26B in the detection area 21, a test reticle on which a pattern for focus measurement is formed on the reticle stage 4 in FIG. The wafer is placed and held on a Z leveling stage 12 shown in FIG. Then, with the inclination of the Z leveling stage 12 fixed at zero and the height set to a predetermined value, focus signals corresponding to these ten detection points are obtained via the multipoint focus position detection device 19. Thereafter, the XY stage 13 on the wafer side is driven to move the portion to be exposed in the detection area 21 of FIG.
The exposed portion is exposed to a test reticle pattern.
In addition, using another exposed portion of the wafer for test baking, the height (focus position) at the Z leveling stage 12 is slightly changed, and ten focus signals are obtained. Expose the test reticle pattern.

Thereafter, by developing the wafer, the detection points 22A to 26A,
In 22B to 26B, the focus position when the test reticle pattern is formed most sharply, that is, the image plane position of the projection optical system 9 is obtained. Thus, the reference level corresponding to the image plane position of the projection optical system 9 of each focus signal corresponding to the detection points 22A to 26A and 22B to 26B is obtained. Similarly, the other detection area 27
The reference level corresponding to the image plane position of the projection optical system 9 is also obtained for the focus signals corresponding to the ten detection points in the above.

Next, in step 102, the reticle 3 having the transfer pattern formed thereon is
Then, the wafer 10 to be exposed to which the photoresist is applied is loaded on the Z leveling stage 12. Then, in synchronization with the start of the scanning of the reticle 3 in the scanning direction RR, the scanning of the wafer 10 in the scanning direction RW is started. Next, in step 103, FIG.
As shown in (a), the center of the exposed portion 30 on the wafer 10 is positioned at the detection area 21 of the multi-point focus position detection device 19.
At the center 21a of the detection point 22A shown in FIG.
To 26A (collectively referred to as “detection point XA”) and detection points 22B to 26B (collectively referred to as “detection point XA”).
B ") is obtained by the multi-point focus position detecting device 19, and these focus signals are supplied to the arithmetic device 18. This is equivalent to obtaining the height (focus position) of the exposed portion 30 at the detection points XA and XB. The average of the heights measured at the five detection points XA is Z _1A , and the average of the heights measured at the five detection points XB is Z _1B .

The center of the exposed portion 30 is
At the time when the center 21a is reached, the height and inclination set in parallel with the Z-leveling stage 12 in FIG. 1 via the Z-leveling stage position detecting device 17, ie, the holder shown in FIG. Center 11 of exposure area 11 on surface 29
The height Z _H0 and the inclination at a are detected, and the height Z _H0 and the inclination are supplied to the arithmetic unit 18. Note that the inclination is represented by the tangent of the inclination angle, and the inclination angle of the holder surface 29 in the XZ plane is θ _HX , and the inclination angle in the YZ plane is θ _HY .

Thereafter, in step 104, the arithmetic unit 18 sets the exposed portion 3 based on the holder surface 29 as a reference.
An average height (average height) Z _1C in the 0 detection area 21 is obtained by the following equation. In the following, the distance D between the center 11a of the exposure area and the center 21a of the detection area can be considered as a prefetch distance.

## EQU1 ## Z _1C = (Z _1A + Z _1B ) / 2-D · tan θ _HX

The arithmetic unit 18 calculates an average inclination (average inclination) in the detection area 21 of the exposed portion 30 with reference to the holder surface 29. Since the surface of the wafer 10 has irregularities due to the process, the inclination of the exposed portion 30 on the wafer 10 refers to the average inclination of the surface in the exposed portion 30, that is, the local surface of the wafer 10. It is a slope. First, assuming that the distance in the X direction between the detection points XA and XB in the X direction is E and the inclination angle corresponding to the average inclination in the XZ plane is θ _1X , the inclination tan θ _1X is as follows.

Tan θ _1X = (Z _1A −Z _1B ) / E-tan θ _HX

The inclination (θ _{1Y in the} inclination angle) in the YZ plane in the detection area 21 of the exposed portion 30 with reference to the holder surface 29 is, for example, the average of the detection points 22A and 22B in FIG. Is Z _1D , the average height of the detection points 26A and 26B is Z _1E , and the interval in the Y direction between the detection points 22A and 26A is E, the following equation is obtained.

Tan θ _1Y = (Z _1D -Z _1E ) / E-tan θ _HY

Next, at step 105, the arithmetic unit 1
8 is to move the exposed portion 30 to the exposure area 11 and perform exposure.
Height to set on the Z leveling stage 12
(Target height) Z_H And the slope to be set (target slope)
Confuse. These target heights Z_H And the target slope are
The height Z of the best imaging plane 28 of the projection optical system 9 which is a quasi-plane ₀ 
And the inclination, the average height and the average inclination of the exposed portion 30 are calculated.
It has been deducted. That is, the target height Z_H Is as follows
become.

## EQU4 ## Z _H = Z ₀ −Z _1C

Further, XZ of the inclination angle of the image plane of the projection optical system 9
_Assuming that the inclination angle in the plane is θ _0X and the inclination angle in the YZ plane is θ _0Y , the inclination angle θ _X in the XZ plane and the inclination angle θ in the YZ plane of the inclination angles of the target inclinations _Y is as follows.

Tan θ _X = tan θ _0X -tan θ _1X , tan θ _Y = tan θ _0Y -tan θ _1Y

Thereafter, in step 106, FIG.
(B), when the exposed portion 30 on the wafer 10 has reached the exposure region 11, the main control system 8 sets the height to set the Z-leveling stage 12 to the target height Z _H And X set on the Z leveling stage 12
The inclination in the Z plane and the inclination in the YZ plane are set to target inclinations tan θ _X and tan θ _Y respectively. At the same time, in step 107, the main control system 8 causes the pulse laser light source 1 in FIG. 1 to emit light, and exposes the pattern of the reticle 3 to the exposed portion 30 on the wafer 10. At this time,
The exposed portion 30 substantially matches the best imaging plane 28.

The above description relates to the operation in the case where a certain exposed portion 30 on the wafer 10 is exposed.
Actually, the exposure operation of FIG. 4 is repeated in a time series for a series of exposed portions on the wafer 10 in the X direction. As described above, according to this example, the height and the inclination of each of the exposed portions on the wafer 10 are read in advance, and the height and the inclination of the Z-leveling stage 12 are adjusted based on the result of the pre-read during the exposure. I have. Therefore, wafer 1
Even if there are local irregularities on the exposure surface 0, the wafer 1
The pattern of the reticle 3 can be exposed on the exposure surface of the wafer 1 in a state where the entire exposure surface is aligned with the image surface of the projection optical system 9.

In the above embodiment, since the pulse laser light source 1 is used as the light source of the exposure light, the exposure timing can be accurately adjusted when the exposed portion 30 reaches the exposure region 11. . However, even when continuous light such as a mercury lamp is used as the exposure light, the height of the exposed portion 30 is read in advance so that the exposed portion 30 can be almost accurately positioned on the image plane of the projection optical system 9 during exposure. Can be adjusted.

As described above, the present invention is not limited to the above-described embodiment, and can take various configurations without departing from the gist of the present invention.

[0038]

According to the first exposure method of the present invention, the height of a region to be exposed on a photosensitive substrate is detected at a position separated by a predetermined distance from a reference point of an exposure region of a projection optical system prior to exposure. Is performed, and focusing is performed at the exposure position of the exposed area based on the result. Therefore, there is an advantage that the focusing can be accurately performed without being affected by the phase delay due to the signal processing time of the focus position detecting means. Further, since the feed speed of the substrate stage on which the photosensitive substrate is mounted does not need to be reduced more than necessary, the throughput does not decrease.

On the substrate stage, when exposing the portion to be exposed, the height is set to a height obtained by adding the difference between the height of the portion to be exposed obtained by prefetching and the height of the image plane to the height set at the time of prefetching. Therefore, the calculation can be performed at high speed and the control is easy. Similarly, according to the second exposure method, the inclination amount of the region to be exposed on the photosensitive substrate is detected prior to the exposure, so that it is affected by the phase delay due to the signal processing time of the inclination angle detecting means. Not
There is an advantage that leveling can be performed accurately. Further, the control is easy without a decrease in throughput.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a projection exposure apparatus to which an exposure method according to an embodiment of the present invention is applied.

FIG. 2 is a plan view showing a relationship between an exposure area and a detection area in FIG.

FIG. 3A is a diagram showing a state of a portion to be exposed during pre-reading,
(B) is a diagram showing a state of a portion to be exposed at the time of exposure.

FIG. 4 is a flowchart illustrating an example of an exposure operation according to the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pulse laser light source 2 illumination optical system 3 reticle 4 reticle stage 5 reticle blind 8 main control system 9 projection optical system 10 wafer 11 exposure area 12 Z leveling stage 13 wafer-side XY stage 16 wafer stage control device 17 position detection for Z leveling stage Device 18 Arithmetic unit 19, 20 Multi-point focus position detection device

Claims (2)

[Claims] 1. A slit-shaped illumination area is illuminated with exposure light, a mask on which a transfer pattern is formed is scanned with respect to the slit-shaped illumination area, and the slit-shaped illumination area is projected onto a projection optical system. A method of exposing the pattern of the mask on the photosensitive substrate by scanning a photosensitive substrate on a substrate stage in synchronization with the mask with respect to the slit-shaped exposure region projected in the step, wherein the mask and the photosensitive substrate After starting the synchronized scanning, the height of the exposed area on the photosensitive substrate and the height of the image plane of the projection optical system are separated from the slit-shaped exposure area by a predetermined interval in a direction opposite to the scanning direction. And the height set on the substrate stage on which the photosensitive substrate is mounted is detected, and the exposed area reaches the slit-shaped exposure area. By setting the height set on the substrate stage to a height obtained by adding the detected difference to the detected height, the height of the exposure area is set to the image plane of the projection optical system. An exposure method characterized in that the height is adjusted to a height. 2. A slit-shaped illumination area is illuminated with exposure light, a mask on which a transfer pattern is formed is scanned with respect to the slit-shaped illumination area, and the slit-shaped illumination area is projected onto a projection optical system. A method of exposing the pattern of the mask on the photosensitive substrate by scanning a photosensitive substrate on a substrate stage in synchronization with the mask with respect to the slit-shaped exposure region projected in the step, wherein the mask and the photosensitive substrate After starting the synchronized scanning, the tilt amount of the exposed area on the photosensitive substrate separated by a predetermined distance from the slit-shaped exposure area in a direction opposite to the scanning direction and the image plane of the projection optical system While detecting the difference with the tilt amount, the tilt amount set on the substrate stage on which the photosensitive substrate is mounted is detected, and the exposed area is within the slit-shaped exposure area. Then, by setting the tilt amount set on the substrate stage to the tilt amount obtained by adding the detected difference to the detected tilt amount, the exposed area is set on the image plane of the projection optical system. An exposure method characterized by being aligned in parallel.