JPH10247618A - Scanning exposure equipment - Google Patents

Abstract

(57) [Abstract] [Problem] Mask (reticle) during mask stage acceleration
The occurrence of an exposure defect due to the displacement of the position is prevented. SOLUTION: A reticle stage RST and a wafer stage WST are relatively scanned through a stage control system 21 for exposure of a reticle pattern by a main controller 30. The reticle stage RST in the relative scanning is performed.
Relative position relationship between reticle R and reticle R
It is detected by the detecting means provided on T. If the detection values of the detecting means are different from each other before the start of the relative scanning of the two stages and at the end of the acceleration, the main controller 30
Stops the exposure. Therefore, the occurrence of exposure failure due to the reticle position shift during the acceleration of the reticle stage is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning exposure apparatus, and more particularly, to a scanning exposure apparatus, for example, a semiconductor device, an image pickup device (C
The present invention relates to a scanning exposure apparatus such as a slit scan and a step-and-scan method for exposing a mask pattern onto a photosensitive substrate in a photolithography process in a manufacturing process of a liquid crystal display element, a thin film magnetic head, or the like.

[0002]

2. Description of the Related Art Conventionally, in a lithography process (a process of forming a resist image of a mask pattern on a substrate) for manufacturing a semiconductor element or the like, a pattern of a mask or a reticle (hereinafter, collectively referred to as a “reticle”) is used. A projection exposure apparatus that exposes a substrate of a wafer (or a glass plate or the like) coated with a photoresist through a projection optical system, for example, a step-and-repeat type reduction projection exposure apparatus (stepper) or the like is used. In such a reduced projection exposure apparatus, a pattern original, which is drawn on a reticle by 5 to 4 times and drawn, is reduced by a projection optical system and is exposed and transferred onto a wafer.

[0003] By the way, semiconductor elements are becoming more and more highly integrated, and the production of ULSIs with a higher degree of integration requires a projection optical system having a higher resolution and therefore a larger numerical aperture. In addition, high throughput is inevitably required for mass production of semiconductor devices, and a projection optical system having a larger exposure area is required. Due to these requirements, the projection optical system has become larger and larger, and the depth of focus obtained due to a large numerical aperture has been reduced. To solve these problems, a scanning exposure system that uses a projection optical system with a small exposure area and relatively scans the reticle and wafer while maintaining the imaging relationship results in a large exposure area. Equipment (scan type exposure equipment)
Has attracted attention and has begun to be put into practical use.

In a scan type exposure apparatus, in order to maintain an image-forming relationship between a reticle and a wafer, scanning of the reticle requires a speed five to four times faster than that of a wafer.
If the scanning speed is low, the throughput as an exposure apparatus is reduced. Therefore, a high scanning speed and a large acceleration are required for achieving a high throughput.

Generally, in a stepper and a scanning type exposure apparatus, a reticle and a wafer are fixed on respective stages via a vacuum suction unit. That is, a minute groove is cut in the contact surface of each stage with the reticle or wafer, and the pressure in the groove is made lower than the atmospheric pressure,
The reticle and the wafer are fixed to each stage by generating a pressure difference.

[0006]

SUMMARY OF THE INVENTION In a scanning exposure apparatus,
Due to the demand for higher throughput and the spread of ultra-sensitive resists such as chemically amplified resists, the scanning speed (scanning speed) and acceleration tend to increase more and more. The reticle or wafer may be displaced in the inward direction by the acceleration. In particular, the reticle stage is subjected to an acceleration larger by the imaging magnification than the wafer stage,
The consequences are severe.

When exposure is performed in a state where the reticle is shifted from a predetermined position on the reticle stage, the pattern transferred onto the wafer is also shifted in position, and accurate overlay is not performed on the existing pattern. , Defective LSI
Will be manufactured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned disadvantages of the prior art, and an object of the present invention is to provide an exposure device which is caused by a displacement of a mask (reticle) during acceleration of a mask stage. An object of the present invention is to provide a scanning exposure apparatus capable of preventing occurrence of a defect beforehand.

[0009]

According to the first aspect of the present invention, a mask (R) and a sensitive substrate (W) are connected to a projection optical system (P).
L) relative to a predetermined scanning direction, and scanning for sequentially exposing and transferring an image of a pattern formed on the mask (R) onto the sensitive substrate (W) via the projection optical system (PL). A mask stage (RST) that holds the mask (R) and is movable in a predetermined stroke range in the scanning direction on a predetermined moving surface; and holds the sensitive substrate (W). A substrate stage (WST) movable in a plane substantially conjugate with the plane of movement of the mask stage;
The mask stage (RST) and the substrate stage (W
(ST) and a stage control system (21) for relative movement in the scanning direction in synchronism with ST); and detection means (36 to 44) for detecting a relative positional relationship between the mask stage and the mask.
Performing relative scanning of the two stages via the stage control system for exposing the mask pattern, and detecting values of the detecting means before the start of the relative scanning of the two stages and at the end of the acceleration are different from each other. In such a case, a control means (30) for interrupting the exposure is provided.

According to this, relative scanning in which the mask stage and the substrate stage are relatively moved in the scanning direction in synchronization with each other is performed by the stage control system. In this specification,
This relative scanning means that each stage is accelerated synchronously from a stop state to a predetermined target speed, and when both stages reach their respective target speeds, both stages are maintained while maintaining a constant speed synchronized state at that speed. It means to move.

In addition, the relative scanning of the two stages is performed by the control means via the stage control system for exposing the mask pattern. The relative positional relationship between the mask stage and the mask in the relative scanning is determined. It is detected by the detecting means. If the detection values of the detecting means are different from each other before the start of the relative scanning and at the end of the acceleration,
Exposure is interrupted by the control means.

Thus, when the mask is displaced on the mask stage due to the acceleration applied to the reticle stage during acceleration after the start of the relative scanning, the relative scanning between the two stages before the start of the relative scanning and at the end of the acceleration are performed. Since the detection values of the detection means are different from each other, the exposure is interrupted by the control means. Therefore, the occurrence of exposure failure due to the displacement of the mask (reticle) during acceleration of the mask stage is prevented beforehand.

The control means may monitor the detection value of the detection means at the start of the relative scan and at the end of the acceleration, or may monitor the value throughout the relative scan.

In this case, as in the second aspect of the present invention, the mask (R) and the substrate stage (WS)
T) or in the case of further including a measuring means (14) for measuring a relative positional relationship with a predetermined reference point on the sensitive substrate (W), the control means (30) is configured to stop after the interruption of the exposure. After measuring the relative positional relationship between the mask and the reference point using the measuring means, the relative scanning of the two stages for exposure may be performed again. In such a case, after the exposure is interrupted, the relative positional relationship between the mask and a predetermined reference point on the substrate stage or the sensitive substrate is measured using a measuring unit, and then the relative scanning of both stages for exposure is performed. Is performed again, it is possible to suppress a decrease in throughput due to interruption.

In this case, at the time of re-exposure, the position of the mask with respect to the predetermined reference point is detected again, so that the substrate stage is moved in consideration of the positional shift of the mask. desirable.

According to a third aspect of the present invention, the mask (R) and the sensitive substrate (W) are relatively moved with respect to the projection optical system (PL) in a predetermined scanning direction, and are formed on the mask (R). A scanning type exposure apparatus for sequentially exposing and transferring the image of the pattern onto the sensitive substrate (W) via the projection optical system (PL), and holding the mask (R) to move the image on a predetermined moving surface. A mask stage (RST) movable in the scanning direction within a predetermined stroke range and minutely movable on the moving surface; and a moving surface of the mask stage (RST) holding the sensitive substrate (W). A substrate stage (WST) movable in a substantially conjugate plane; a stage control system (21) for synchronously moving the mask stage and the substrate stage in the scanning direction; and a mask stage (RST). Before Detecting means for detecting a relative positional relationship with the mask (R); if the detection values of the detecting means by the stage control system before the start of relative scanning of the two stages and at the end of acceleration are different from each other, Control means (30) for correcting the in-plane position of the mask stage based on the two detected values and performing exposure.

According to this, the relative scanning in which the mask stage and the substrate stage are relatively moved in the scanning direction in synchronization with each other is performed by the stage control system. When the detection values of the detection means before and after the relative scanning of the two stages by the stage control system are different from each other by the control means, the in-plane position of the mask stage is determined based on the two detection values. The correction is performed and the exposure is performed.

Thus, when the mask is displaced from the mask stage due to acceleration applied to the mask stage during acceleration after the start of the relative scan, the detection values of the detection means before the start of the relative scan and at the end of the acceleration. , The in-plane position of the mask stage is corrected and exposure is performed. Therefore, it is possible to prevent the occurrence of exposure failure due to the displacement of the mask (reticle) when the mask stage is accelerated, and the exposure is not stopped.
There is no decrease in throughput.

In this case, even during the scanning exposure, the control means constantly monitors the output of the detection means, and when there is a change in the output of the detection means, the control means controls the mask stage based on the detected values before and after the change. Exposure may be continued while correcting the in-plane position.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows the entire configuration of a scanning exposure apparatus 10 according to the embodiment. The scanning exposure apparatus 10 is a projection exposure apparatus of a so-called step-and-scan exposure system.

The scanning exposure apparatus 10 has an illumination optical system I for illuminating a reticle R as a mask with illumination light for exposure.
OP, reticle stage RST as a mask stage for holding reticle R as a mask, projection optical system P
L, a wafer stage WST as a substrate stage for holding a wafer W as a substrate, and a control system for these components.

The illumination optical system IOP includes, for example, a collimator lens, a fly-eye lens, a relay lens system, a reticle blind, a condenser lens and the like (all not shown), and is substantially uniform by illumination light from a light source (not shown). A predetermined slit-shaped illumination area IAR (see FIG. 2) defined by the reticle blind on the reticle R is illuminated from above with an appropriate illuminance. As the illumination light, for example, Kr
Excimer laser light such as F excimer laser light and ArF excimer laser light, harmonics of copper vapor laser and YAG laser,
Alternatively, ultraviolet emission lines (g-line,
i-line etc.) are used.

The reticle stage RST is mounted on a reticle base 12 arranged along a horizontal plane (XY plane). A reticle R is mounted on the reticle stage RST by a vacuum suction unit (this will be described later). Do)
Has been fixed through. Reticle stage RST is
In order to position the reticle R, the reticle base 12 is configured to be finely drivable two-dimensionally (in the X-axis direction, in the Y-axis direction orthogonal thereto, and in the rotation direction around the Z-axis orthogonal to the XY plane). .

The reticle stage RST is a reticle driving section (not shown) composed of a linear motor or the like.
Thereby, it is possible to drive at a designated scanning speed in a predetermined scanning direction (here, the Y direction). In reticle stage RST, the entire surface of reticle R has at least the optical axis of the illumination optical system (optical axis AX of projection optical system PL described later).
Has a movement stroke enough to cross the same.

A reticle laser interferometer (hereinafter, referred to as a “reticle interferometer”) 1 is provided at an end of reticle stage RST.
A movable mirror 15 for reflecting the laser beam from 6 is fixed, and the position of reticle stage RST in the XY plane is always detected by reticle interferometer 16 at a predetermined resolution. Here, on the reticle stage RST, actually,
As shown in the plan view of FIG. 2, two movable mirrors 15Y1, 15 having reflection surfaces orthogonal to the Y direction which is the scanning direction.
A moving mirror 15X having a reflecting surface orthogonal to the non-scanning direction (X direction) is provided, and the reticle interferometer also has two axes in the scanning direction and one in the non-scanning direction X direction.
Although they are provided with shafts, these are typically shown as a movable mirror 15 and a reticle interferometer 16 in FIG.

The position information of the reticle stage RST from the reticle interferometer 16 is supplied to the stage control system 21 and the main controller 30 via the stage control system 21. The stage control system 21 translates the reticle stage RST. The reticle stage RST is calculated via a reticle driving unit (not shown) based on the calculation result.
Drive control. Note that the main controller 30 uses the reticle alignment microscope 14 as a measuring unit disposed above the reticle stage RST to control the reticle R.
A relative positional relationship between the upper alignment marks M1 and M2 (see FIG. 3) and a reference mark on a reference plate (not shown) on wafer stage WST is measured, and a predetermined value is determined by stage control system 21 based on the measurement result. Since the initial position of the reticle stage RST is determined so that the reticle R is accurately positioned at the reference position, the position of the reticle R can be determined with sufficiently high accuracy only by measuring the position of the movable mirror 15 with the reticle interferometer 16. It will be measured in

The projection optical system PL includes a reticle base 1
2, the direction of the optical axis AX (coincident with the optical axis of the illumination optical system) is defined as the Z-axis direction. Here, a predetermined reduction magnification (for example, 1 /
5 or 1/4). Therefore, when the illumination area IAR (see FIG. 2) of the reticle R is illuminated by the illumination light from the illumination optical system IOP, the illumination light IL that has passed through the reticle R causes the illumination area IAR of the reticle R to pass through the projection optical system PL. A reduced image of the circuit pattern is formed on a wafer W having a surface coated with a photoresist (photosensitive material).

The wafer stage WST has a wafer base 19 disposed below the projection optical system PL in FIG.
The upper part can be moved in the XY two-dimensional directions. Wafer W is vacuum-sucked on wafer stage WST via a wafer holder (not shown). Wafer stage WST
Illuminates a plurality of shot areas on the wafer W with the illumination area I
As described above, it is possible to move not only in the scanning direction (Y direction) but also in the direction (X direction) orthogonal to the scanning direction so that it can be located in the exposure area IA conjugate with the AR. . The wafer stage WST is driven in the XY two-dimensional directions by a wafer stage driving unit (not shown) such as a motor.

A wafer laser interferometer (hereinafter, referred to as "wafer interferometer") 18 is provided at an end of the upper surface of wafer stage WST.
Moving mirror 17 for reflecting the laser beam from
The position of wafer stage WST in the XY plane is constantly detected by wafer interferometer 18 at a predetermined resolution. Here, actually, a Y moving mirror having a reflecting surface orthogonal to the scanning direction and an X moving mirror having a reflecting surface orthogonal to the non-scanning direction are provided on wafer stage WST. The interferometer is also provided with an X interferometer for measuring the position in the X-axis direction and a Y interferometer for measuring the position in the Y-axis direction, but these are typically shown as a moving mirror 17 and a wafer interferometer 18 in FIG. Have been. The position information (or speed information) of wafer stage WST is supplied to stage control system 21 and main controller 30 via this.
In the stage control system 21, this position information (or speed information)
The wafer stage WST is controlled based on.

In the present embodiment, upon exposure of the reticle pattern onto the wafer W, the stage control system 21 controls the laser interferometer 16,
The wafer stage WST and the reticle stage RST are scanned synchronously while monitoring the measurement value of 18, while maintaining the imaging relationship between the reticle R and the wafer W.

The scanning exposure will be described in more detail. As shown in FIG. 2, the scanning direction of the reticle R (Y direction)
The reticle R is illuminated by a rectangular (slit-shaped) illumination area IAR having a longitudinal direction perpendicular to the reticle R, and the reticle R is scanned (scanned) at a speed VR in the -Y direction during exposure. The illumination area IAR (the center substantially coincides with the optical axis AX) is projected onto the wafer W via the projection optical system PL,
A slit-shaped exposure area IA is formed. Since the wafer W has an inverted image relationship with the reticle R, the wafer W is scanned at a speed VW in synchronization with the reticle R in a direction (+ Y direction) opposite to the direction of the speed VR, and a shot area SA on the wafer W is formed. Can be exposed. Scan speed ratio VW
/ VR accurately corresponds to the reduction magnification of the projection optical system PL, and the pattern of the pattern area PA of the reticle R is accurately reduced and transferred onto the shot area SA on the wafer W. The width of the illumination area IAR in the longitudinal direction is the reticle R
It is set so as to be wider than the upper pattern area PA and narrower than the maximum width of the light-shielding area ST, and the entire pattern area PA is illuminated by scanning.

Returning to FIG. 1, on the side of the projection optical system PL,
An off-line for detecting the position of an alignment mark (wafer mark) attached to each shot area on the wafer W
A wafer alignment microscope 20 including an Axis type high magnification image sensor is provided. The measurement result of the alignment microscope 20 is supplied to a main controller 30 that controls the operation of the entire apparatus.

Prior to the above-described scanning exposure, it is necessary to accurately adjust the positional relationship between the wafer W and the reticle R (reticle alignment and wafer alignment). This is performed by detecting the positions of the alignment marks formed on the wafer W and the reticle R using the reticle alignment microscope 14 and the wafer alignment microscope 20, respectively, and obtaining the positional relationship. Of course, before that, measurement of the positional relationship between the two microscopes 14 and 20 (baseline measurement) is performed, but the sequence is the same as that of the conventional exposure apparatus, and the description is omitted here.

In the scanning exposure apparatus 10 of this embodiment, the operation of scanning (scanning) each shot area on the wafer W and the step of moving the wafer stage WST to the exposure start position of the next shot are repeated. Exposure of a reticle pattern is sequentially performed on each shot area on the wafer W by a step-and-scan method.

Next, the configuration of the reticle stage RST, which is a characteristic component of the present embodiment, will be described with reference to FIG. FIG. 3 is a plan view of the reticle stage RST (a view as seen from the direction of the illumination optical system IOP). In FIG. 3, vacuum suction parts 22 a to 22 a to suction reticle R are provided at approximately four corners on the upper surface of reticle stage RST.
22d are provided, and these vacuum suction portions 22a to 22d are provided.
Reticle R is fixed by suction on reticle stage RST via 22d. The vacuum suction parts 22a to 22d are
The circuit pattern is formed at the center of the reticle R, and is formed at a position avoiding the reticle alignment marks M1 and M2.

The pattern surface of the reticle R facing the vacuum suction portions 22a and 22d (the surface on the back side of the paper in FIG. 3).
Have lattice marks 24a and 24 having periodicity in the Y direction.
b are formed respectively. In the present embodiment, these lattice marks 24a, 24b and reticle stage RST
Is provided on reticle stage RST to detect a positional relationship with the reticle stage RST.

FIG. 4A shows the vacuum suction portion 22d of FIG.
An enlarged view of the vicinity is shown, and FIG.
FIG. 4A is a schematic sectional view taken along line BB of FIG.
As shown in these figures, the grooves 26 necessary for vacuum suction
Is formed in a transparent suction portion 28 made of quartz glass or the like, and inside the groove 26 is formed a suction hole 30 and the suction hole 30.
Is suctioned by a vacuum suction force of an external vacuum pump (not shown) through a pipe 32 connected to the groove 26, a negative pressure is generated in the groove 26, and the reticle R is sucked by a pressure difference between the inside and the outside of the groove 26. The surface of the transparent suction section 28 opposite to the reticle R (FIG. 4)
On the lower surface in (B), two lattice marks 34a and 34b having periodicity in the Y direction are formed at predetermined intervals.

A light transmitting optical system comprising a light source 36 such as a semiconductor laser, a shaping lens 38, a half mirror 40 and a mirror 42, and a detection device comprising a light detector 44 are provided below the attraction section 28 inside the reticle stage RST. A position sensor is provided as a means. Here, the operation of each component of the position sensor will be described.

Light beam L emitted from a light source 36 such as a semiconductor laser
Is divided by the half mirror 40 via the shaping lens 38. The light beam L1 reflected by the half mirror 40 is
One of the grating marks 34a is irradiated perpendicularly, and the + 1st-order diffracted light + L11 generated by this irradiates the grating mark 24b formed on the pattern surface of the reticle R from a predetermined direction (−1st-order direction). On the other hand, the luminous flux L2 transmitted through the half mirror 40 irradiates the grating mark 34b vertically through the mirror 24, and the -1st-order diffracted light -L21 generated by this is reflected by the grating mark 24b formed on the pattern surface of the reticle R.
From a predetermined direction (+ 1-order direction). By the irradiation of the pair of first-order diffracted lights (+ L11, -L21), interference fringes having periodicity in the Y direction are formed in the lattice mark 24b, and the interference fringes reflected by the lattice mark 24b (the diffracted light ( + L11, -L21) to illuminate the grid mark 2
4b) is received by the light detector 42.

Here, the above-described interference fringe grid mark 24b is used.
Of the interference fringes (that is, the position of the reticle stage RST that is the source of the interference fringes) and the lattice mark 24
b, that is, the position of the reticle R, the reflected light intensity Si
By monitoring g, it is possible to determine whether or not the reticle R has deviated from the reticle stage RST.

Although not shown, the vacuum suction unit 22
The portion a is also provided with a position sensor similar to that shown in FIG. 3B for generating interference fringes on the lattice mark 24a and detecting the intensity of the reflected light, and the reticle R is similarly connected to the reticle stage RST. It can be determined whether or not the position has shifted with respect to.

In the present embodiment, main controller 30 monitors the above-mentioned reflected light intensity Sig when the above-described reticle alignment and wafer alignment are completed, and stores it in an internal memory (not shown). Then, main controller 50 starts the above-described relative scanning of reticle stage RST and wafer stage WST via stage control system 21, and when both stages are accelerated to their respective target speeds and reach a constant speed synchronization state. (At the end of the acceleration), the wafer W
Prior to the start of the exposure operation on the
Is monitored, and if the value is different from the value previously stored in the internal memory, it is determined that the reticle R has been displaced due to the acceleration acting on the reticle stage RST, and the exposure is stopped. Thereby, reticle stage R
It is possible to prevent the occurrence of exposure failure (overlapping displacement) due to the displacement (adsorption displacement) of the reticle R during the ST movement.

On the other hand, prior to the start of the exposure operation on wafer W, if the value obtained by monitoring reflected light intensity Sig again is substantially equal to the previously stored value, main controller 30 sets illumination optical system IOP To start exposure. Here, the exposure start command refers to an instruction to oscillate the excimer laser when the light source is, for example, an excimer laser, or to release a shutter in the illumination optical system IOP.

When the main controller 30 determines the displacement of the reticle R and stops the exposure as described above, various sequences can be considered as the subsequent sequence. For example, an error message (buzzer (A sound, blinking of a lamp, etc.) may be issued to an operator via an alarm device (not shown), and a sequence may be set to wait for an instruction (operation) from the operator.

However, since the continuation of the exposure interruption state causes a decrease in throughput, the main control device 30
When the displacement of the reticle R is detected, it is desirable to stop the exposure operation immediately and set a sequence for immediately executing the reticle alignment or the baseline measurement again immediately. By doing so, the position of the reticle R is returned to the original position, and the scanning exposure is performed again, or the position after the position shift is performed, using the result of the reticle alignment or the baseline measurement without substantially reducing the throughput. , The position of the reticle R can be correctly detected again, and the scanning exposure can be performed again while controlling the position of the wafer stage WST in consideration of the reticle displacement.

In the above description, for the sake of simplicity, the position sensor for measuring the relative positional relationship between the reticle stage RST and the reticle R detects only a positional displacement in one-dimensional direction (mainly the scanning direction). However, the present invention is not limited to this. In addition to the above-described position sensor, grid marks having periodicity in the X direction are formed on the pattern surface of the reticle R and the lower surface of the suction unit 28, respectively. It is a matter of course that a two-dimensional displacement of the reticle R may be detected by providing a position sensor for detecting a displacement in the X direction.

In the above embodiment, a case has been described in which the position sensor for measuring the relative positional relationship between the reticle stage RST and the reticle R is configured using a homodyne detection system as shown in FIG. 4B. However, instead of this, a position sensor is configured using a heterodyne detection system in which the frequencies of the light beams incident on the grating marks 34a and 34b are slightly different, and the intensity of the reflected light from the grating mark 24b is changed instead of the intensity. If the reticle R is shifted based on the heterodyne frequency (the difference between the frequencies), the period of the lattice mark 24b, and the detected phase change, It is also possible to detect the shift amount.

When a position sensor comprising such a heterodyne detection system is employed, the main controller 30
If the detected values (phases of the intensity change) of the position sensors before the start of the relative scanning of the reticle stage RST and the wafer stage WST by the stage control system 21 and at the end of the acceleration of both stages are different from each other, the phase change Exposure can be started after correcting the in-plane position of reticle stage RST based on (the two detected values). Thus, after the start of the relative scanning, the reticle stage R being accelerated is accelerated.
Even when the reticle R is displaced due to the acceleration applied to the ST, the in-plane position of the reticle stage RST is determined based on the detected values of the position sensors before the start of the relative scan and at the end of the acceleration without stopping the exposure. Is corrected and exposure is performed. Therefore, it is possible to prevent the occurrence of exposure failure due to the displacement of the reticle R during the acceleration of the reticle stage WST, and to prevent the exposure from being stopped because the exposure is not stopped.

In this case, the main controller 50 constantly monitors the output of the position sensor even during the scanning exposure.
If a phase change has occurred, the in-plane position of reticle stage WST is determined based on the phase before and after the change.
Exposure may be continued while correcting through step 1.

When a position sensor and a grid mark to be detected are arranged at two relatively distant points on the reticle stage RST (for example, the positions of the vacuum suction portions 22a and 22d in FIG. 3), the reticle R Of the reticle R can be measured. Even when the reticle R has a rotational deviation, the reticle stage R
It is possible to cancel the rotational deviation by rotating ST.

As described above, when the heterodyne detection system is employed as the position sensor, even when the reticle R has slipped from the reticle stage due to the acceleration of the reticle stage WST, the time required for its return (see above). Since no time is required for the reticle alignment, etc., there is an advantage that the throughput is not reduced at all.

When the position sensor shown in FIG. 3B according to the above embodiment is employed, it is premised that grid marks 24a and 24b are provided on the reticle R. As shown in FIG. 5, an irradiation optical system 51a that irradiates a side surface of the reticle R with a light beam at a predetermined angle.
(Or 51b) and a light receiving optical system 5 for receiving the reflected light
2a (or 52b), the position detection system 53A (or 53B) of the oblique incidence type detects the positional deviation of the reticle R with respect to the reticle stage RST without providing a special mark on the reticle R. In this case, the reflected light is incident on the light receiving element in the light receiving optical system 52a (or 52b) similarly to the oblique incident light type focus detection system usually used in the projection exposure apparatus. It is also possible to detect the amount of displacement according to the position or the like. Also, in this case, as shown in FIG.
By providing the position detection system 53A for detecting the position in the scanning direction and the position detection system 53B in the non-scanning direction, it is possible to detect the displacement of the reticle R in the XY two-dimensional directions. Of course, also in this case, if two position detection systems are provided in either the scanning direction or the non-scanning direction, it is also possible to detect the rotational displacement amount of the reticle R.

[0054]

As described above, claims 1 to 3 are described.
According to the invention described in (1), it is possible to prevent the occurrence of exposure failure due to the displacement of the mask (reticle) at the time of acceleration of the mask stage, thereby preventing the manufacture of a defective LSI. It is possible to provide an exposure apparatus which has high performance and is excellent.

In particular, according to the third aspect of the present invention, there is also an effect that no deterioration in overlay accuracy and no decrease in throughput due to a positional shift of the mask (reticle) during acceleration of the mask stage occurs.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a scanning exposure apparatus according to an embodiment.

FIG. 2 is a perspective view showing a state of scanning a reticle and a wafer in the scanning exposure apparatus of FIG.

FIG. 3 is a plan view of a reticle stage portion of FIG. 1;

4A is an enlarged view of the vicinity of a vacuum suction part 22d in FIG. 3, and FIG. 4B is a cross-sectional view taken along a line BB in FIG. 4A.

FIG. 5 is a diagram for explaining another configuration example of the detection means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Scanning exposure apparatus 14 Reticle alignment microscope (measuring means) 21 Stage control system 36 Light source (part of detecting means) 38 Shaping lens (part of detecting means) 40 Half mirror (part of detecting means) 42 Mirror (detection) Part of means) 44 Optical detector (part of detection means) 50 Main controller R Reticle (mask) W Wafer (sensitive substrate) PL Projection optical system RST Reticle stage (mask stage) WST Wafer stage (substrate stage)

Claims (3)

[Claims] 1. A mask and a sensitive substrate are relatively moved in a predetermined scanning direction with respect to a projection optical system, and an image of a pattern formed on the mask is sequentially exposed on the sensitive substrate via the projection optical system. A scanning exposure apparatus for transferring, comprising: a mask stage capable of holding the mask and moving on a predetermined moving surface within a predetermined stroke range in the scanning direction; and a moving surface of the mask stage holding the sensitive substrate. A substrate stage movable in a plane substantially conjugate with the stage; a stage control system for synchronously moving the mask stage and the substrate stage in the scanning direction; and a relative positional relationship between the mask stage and the mask. Detecting means for detecting; performing relative scanning of the two stages via the stage control system for exposing the mask pattern; When the detected value of said detecting means with the 査 before the start acceleration at the end are different from each other, the scanning exposure apparatus having an interrupting control means exposure. 2. The apparatus according to claim 1, further comprising: a measuring unit configured to measure a relative positional relationship between the mask and a predetermined reference point on the substrate stage or the sensitive substrate. 2. The scanning type exposure apparatus according to claim 1, wherein the relative scanning between the two stages for the exposure is performed again after measuring a relative positional relationship between the mask and the reference point using a measuring unit. . 3. A mask and a sensitive substrate are relatively moved with respect to a projection optical system in a predetermined scanning direction, and an image of a pattern formed on the mask is sequentially exposed on the sensitive substrate via the projection optical system. A scanning exposure apparatus for transferring, the mask stage being capable of holding the mask and moving on a predetermined moving surface within a predetermined stroke range in the scanning direction within a predetermined stroke range, and being capable of micro-moving on the moving surface; A substrate stage capable of holding a sensitive substrate and moving in a plane substantially conjugate with a moving surface of the mask stage; a stage control system for synchronously moving the mask stage and the substrate stage relative to each other in the scanning direction; Detecting means for detecting a relative positional relationship between the mask stage and the mask; and detecting the relative position of the two stages by the stage control system before the start of relative scanning and at the end of acceleration. If the detected value of the unit are different from each other, the scanning exposure apparatus and a control means for performing exposure is corrected in-plane position of the mask stage based on the two detection values.