JPH10163097A - Projection light-exposure device and projection light-exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance still more the throughput. SOLUTION: Two wafer stages WS1, WS2 can be moved independently and two-dimensionally on a base boad 12, and while wafer replacement, search alignment and fine alignment are made on the wafer stage WS1 under one alignment system 24a, a wafer W2 held on the wafer stage WS2 under a projection optical system PL is exposed to lights by a step and scan method. When both operations on the wafer stages WS1, WS2 are finished, the wafer stage WS1 is moved under the projection optical system PL and the wafer stage WS2 is moved under an alignment system 24b, and exchangement of operations is made. Thus, a series of lightexposing operations are parallel-processed using the wafer stages WS1, WS2, so that as a process time is lessened, and the throughput can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus and a projection exposure method, and more particularly to a projection exposure apparatus for projecting and exposing a pattern image formed on a mask onto a sensitive substrate via a projection optical system. The present invention relates to a projection exposure method, in particular, by independently moving two substrate stages,
The feature is that exposure processing and other processing are performed in parallel.

[0002]

2. Description of the Related Art Conventionally, various exposure apparatuses have been used for manufacturing a semiconductor element or a liquid crystal display element by a photolithography process. At present, however, a photomask or a reticle (hereinafter referred to as a “reticle”) is used. Projection exposure for transferring a pattern image (collectively referred to as a "sensitive substrate") onto a substrate such as a wafer or a glass plate having a surface coated with a photosensitive material such as a photoresist via a projection optical system. The device is commonly used. In recent years, as a projection exposure apparatus, a sensitive substrate is placed on a two-dimensionally movable substrate stage, and the sensitive substrate is stepped on the substrate stage, and a reticle pattern image is formed on the sensitive substrate. The so-called step-and-repeat type reduction projection exposure apparatus (so-called stepper) is mainly used to repeat the operation of sequentially exposing each shot area.

Recently, a step-and-scan type projection exposure apparatus (for example, a scanning exposure apparatus as disclosed in Japanese Patent Application Laid-Open No. Hei. Devices) have also become relatively popular. This step-and-scan projection exposure apparatus can expose a large field with a smaller optical system compared to a stepper, making it easier to manufacture the projection optical system and reducing the number of shots due to the large field exposure. Therefore, high throughput can be expected, and the reticle and wafer are relatively scanned with respect to the projection optical system, which has an averaging effect, and can improve distortion and depth of focus. Further, as the degree of integration of semiconductor elements increases from 16M (Mega) to 64M DRAM and further to 256M, 1G (Giga) in the future, a large field becomes indispensable. It is said that scanning projection exposure apparatuses will become mainstream.

[0004]

Since this type of projection exposure apparatus is mainly used as a mass production machine for semiconductor devices and the like, it is necessary to determine how many wafers can be subjected to exposure processing within a certain period of time. It is inevitably required to improve the processing capacity, that is, the throughput.

In this regard, in the case of a step-and-scan type projection exposure apparatus, when a large field is exposed, as described above, the number of shots to be exposed in a wafer is reduced, so that an improvement in throughput is expected. However, since exposure is performed during constant-speed movement by synchronous scanning between the reticle and wafer, acceleration / deceleration areas are required before and after the constant-speed movement area, and a shot having a size equivalent to the shot size of a stepper is assumed. In the case of exposing, there is a possibility that the throughput may be reduced rather than the stepper.

The flow of processing in this type of projection exposure apparatus is roughly as follows.

First, a wafer loading step of loading a wafer on a wafer table using a wafer loader is performed.

Next, a search alignment step is performed in which a rough alignment of the wafer is detected by a search alignment mechanism. This search alignment step is specifically performed, for example, based on the outer shape of the wafer or by detecting a search alignment mark on the wafer.

Next, a fine alignment step for accurately determining the position of each shot area on the wafer is performed. This fine alignment process is generally performed by EGA
(Enhanced Global Alignment) method is used. In this method, a plurality of sample shots in a wafer are selected, and the positions of alignment marks (wafer marks) attached to the sample shots are sequentially measured. Based on the measurement result and the design value of the shot array, a statistical operation is performed by a so-called least square method or the like to obtain all shot array data on the wafer (see Japanese Patent Application Laid-Open No. 61-44429). The coordinate position of each shot area can be obtained with relatively high accuracy at high throughput.

Next, while sequentially positioning each shot area on the wafer to the exposure position based on the coordinate position of each shot area obtained by the above-described EGA method and the baseline amount measured in advance, the projection optical system is An exposure step of transferring a reticle pattern image onto a wafer via the reticle is performed.

Next, a wafer unloading step of unloading the exposed wafer on the wafer table using a wafer unloader is performed. This wafer unloading step is performed simultaneously with the above-described wafer loading step of the wafer to be subjected to the exposure processing. That is, a wafer exchange step is constituted by the above and.

As described above, in the conventional projection exposure apparatus, four operations such as wafer exchange → search alignment → fine alignment → exposure → wafer exchange are repeatedly performed using one wafer stage. .

The throughput THOR [sheets / time] of this type of projection exposure apparatus is as follows: T1 is the wafer exchange time, T2 is the search alignment time, T3 is the fine alignment time, and T4 is the exposure time. It can be expressed as the following equation (1).

THOR = 3600 / (T1 + T2 + T3 + T4) (1) The operations of T1 to T4 are performed in the order of T1 → T2 → T3 → T4 → T
.. Are sequentially (sequentially) repeatedly executed. Therefore, if the speed of each element from T1 to T4 is increased, the denominator becomes smaller, and the throughput THOR can be improved. However, the above-described T1 (wafer replacement time) and T2 (search alignment time) are relatively small in improvement because only one operation is performed for one wafer. In the case of T3 (fine alignment time), the throughput can be improved by reducing the number of shot samples or reducing the measurement time of a single shot when using the above-described EGA method. Since the accuracy is degraded, T3 cannot be easily reduced.

T4 (exposure time) includes a wafer exposure time and a stepping time between shots. For example, in the case of a scanning projection exposure apparatus such as a step-and-scan method, it is necessary to increase the relative scanning speed between the reticle and the wafer by the amount of shortening the wafer exposure time. The scanning speed cannot be easily increased.

In this type of projection exposure apparatus, in addition to the above throughput, important conditions include resolution, depth of focus (DOF: Depth of Forcus), and line width control accuracy. The resolution R is defined as follows: the exposure wavelength is λ, and the numerical aperture of the projection lens is ND. A. (Numerical Aperture), λ / N. A. And the depth of focus DOF is λ /
(NA) ² .

Therefore, in order to improve the resolution R (decrease the value of R), the exposure wavelength λ must be reduced or the numerical aperture N. A. Need to be larger. In particular, since the density of semiconductor elements and the like has been increasing recently and the device rule has become 0.2 μmL / S (line and space) or less, illumination is required to expose these patterns. A KrF excimer laser is used as a light source. However, as described above, it is inevitable that the degree of integration of semiconductor devices will further increase in the future,
It is desired to develop a device having a light source shorter in wavelength than KrF. Representative examples of a next-generation apparatus having such a shorter wavelength light source include an apparatus using an ArF excimer laser as a light source, an electron beam exposure apparatus, and the like.
In the case of an excimer laser, light hardly transmits in a place where oxygen exists, high output is difficult to be obtained, and a laser lifetime is short, and a technical problem that an apparatus cost is high is piled up. In the case of an exposure apparatus, there is a disadvantage that the throughput is significantly lower than that of an optical exposure apparatus. Therefore, the reality is that the development of a next-generation apparatus whose main purpose is to shorten the wavelength is not as expected.

Another technique for increasing the resolution R is to use a numerical aperture N.P. A. May be increased, but N.I. A.
Has a demerit that the DOF of the projection optical system is reduced. This DOF is UDOF (User D
epth of Forcus: part used on the user side: pattern step, resist thickness, etc.) and the overall focal difference of the apparatus itself. Until now, since the ratio of UDOF was large, the direction to increase the DOF was the main axis of development of the exposure apparatus, and as a technique for increasing the DOF, for example, deformed illumination or the like has been put to practical use.

By the way, in order to manufacture a device,
It is necessary to form a pattern combining L / S (line and space), isolated L (line), isolated S (space), and CH (contact hole) on the wafer. Exposure parameters for performing optimal exposure differ for each pattern shape such as S and isolated lines. For this reason, conventionally, using a method called ED-TREE (excluding CHs with different reticles), the resolution line width is within a predetermined tolerance with respect to a target value, and a predetermined D
A common exposure parameter (a coherence factor σ, NA, exposure control accuracy, reticle drawing accuracy, and the like) for obtaining an OF is obtained, and is used as a specification of an exposure apparatus. However, it is thought that there will be the following technical flows in the future.

Due to the improvement of the process technology (flattening on the wafer), the pattern is lowered and the resist thickness is reduced.
OF may be in the order of 1 μm → 0.4 μm or less.

The exposure wavelength is shortened from g-line (436 nm) to i-line (365 nm) to KrF (248 nm). However, only light sources up to ArF (193) are being studied in the future, and the technical hurdle is high. After that, it shifts to EB exposure.

It is expected that scanning exposure such as step-and-scan will become the mainstream of steppers instead of static exposure such as step-and-repeat.
This technique enables a large field exposure with a projection optical system having a small diameter (especially in the scanning direction), and a higher N.D. A.
Is easy to realize.

Against the background of the technical trends described above, the double exposure method has been reviewed as a method for improving the limit resolution, and this double exposure method is used for a KrF exposure device and a ArF exposure device in the future. Attempts to expose up to 1 μmL / S are being considered. Generally, the double exposure method is roughly classified into the following three methods.

(1) L / S and isolated lines having different exposure parameters are formed on different reticles, and double exposure is performed on the same wafer under optimum exposure conditions.

(2) When the phase shift method or the like is introduced, the limit resolution of the L / S is higher than that of the isolated line in the same DOF.
By utilizing this, all patterns are formed with L / S on the first reticle, and L / S is formed on the second reticle.
An isolated line is formed by thinning S.

(3) In general, an isolated line is smaller than N / S A. High resolution can be obtained with (However,
DOF is smaller). Therefore, all the patterns are formed by isolated lines, and the L / S is formed by combining the isolated lines formed by the first and second reticles, respectively.

The above double exposure method has two effects, that is, an improvement in resolution and an improvement in DOF.

However, in the double exposure method, since the exposure processing needs to be performed a plurality of times using a plurality of reticles, the exposure time (T4) becomes twice or more as compared with the conventional apparatus, and the throughput is largely deteriorated. Because of the inconvenience of doing
In reality, the double exposure method is not considered seriously,
Conventionally, resolution and depth of focus (DOF) have been improved by ultraviolet exposure wavelength, modified illumination, phase shift reticle, and the like.

However, the double exposure method described above
When used in an rF or ArF exposure apparatus, exposure up to 0.1 μmL / S is realized, so that a 256 M, 1 G DRA
There is no doubt that this is a powerful option for the development of the next-generation machine for mass production of M, and the development of new technology has been anticipated to improve the throughput, which is the problem of the double exposure method, which is the bottleneck for this. Was.

The present invention has been made under such circumstances, and an object of the present invention is to provide a projection exposure apparatus capable of further improving the throughput.

Another object of the present invention is to provide a projection exposure method capable of further improving the throughput.

[0032]

If the four operations described above, that is, wafer exchange, search alignment, fine alignment, and exposure can be performed in at least two operations and performed simultaneously in parallel, these four operations are sequentially performed. The throughput can be improved as compared with the case where the above is performed. The present invention has been made in view of this point, and employs the following configuration. That is, the invention according to claim 1 is a projection exposure apparatus for projecting and exposing an image of a pattern formed on a mask (R) onto a sensitive substrate (W1, W2) via a projection optical system (PL). A first substrate stage (WS1) holding a sensitive substrate (W1) and movable in a two-dimensional plane; and a sensitive substrate (W2).
A second substrate stage (WS2) that can move independently of the first substrate stage (WS1) in the same plane as the first substrate stage (WS1), and the projection optical system (PL) Separately provided, the substrate stage (WS
1, WS2) or on the substrate stage (WS1, WS2)
2) At least one alignment system (for example, 24) for detecting a mark on the sensitive substrate (W1, W2) held in
a) the position of the first substrate stage (WS1) in the first axial direction from one side of a first axis passing through the projection center of the projection optical system (PL) and the detection center of the alignment system (24a). A first measurement axis (BI1X) for measuring the
From the other side in the first axial direction, the second substrate stage (W
S2) a second length measurement axis (BI2X) for measuring the position in the first axis direction, and a third length measurement perpendicular to the first axis at the projection center of the projection optical system (PL). Shaft (BI3
Y), and a fourth measurement axis (BI4Y) perpendicular to the first axis at the detection center of the alignment system (24a), and the first substrate is defined by these measurement axes (BI1X to BI4Y). An interferometer system for measuring the two-dimensional positions of the stage and the second substrate stage (WS1 and WS2).

According to this, the first substrate stage and the second substrate stage
Sensitive substrates are respectively held on the substrate stage and can be independently moved in a two-dimensional plane, and are held on or on the substrate stage by at least one alignment system provided separately from the projection optical system. A mark on the sensitive substrate is detected, and the two-dimensional positions of the first substrate stage and the second substrate stage are respectively measured by the first to fourth measurement axes of the interferometer system. As the length measurement axes of the interferometer system, the first substrate stage and the second length measurement axis extend along a first axis direction in which the first length measurement axis and the second length measurement axis pass through the projection center of the projection optical system and the detection center of the alignment system. Two stages are provided on one side and the other side of the substrate stage, and the first
The first axial position of the substrate stage is measured, and the first axial position of the second substrate stage is measured by the second measurement axis. The third measurement axis is the first projection center of the projection optical system.
The fourth measurement axis is provided to intersect perpendicularly with the axis at the detection center of the alignment system.

For this reason, the marks formed on the two substrate stages can be detected by using the alignment system. When the marks are detected, the two-dimensional position of the first substrate stage is mutually detected at the detection center of the alignment system. Is measured by an interferometer of a first measuring axis and a fourth measuring axis perpendicular to
The two-dimensional position of the second substrate stage is measured by the interferometers of the second and fourth measurement axes that intersect perpendicularly at the detection center of the alignment system, and the positions of both stages have no Abbe error Is measured accurately.

On the other hand, when the mask pattern is exposed by the projection optical system, the two-dimensional position of the first substrate stage and the third length measurement axis perpendicular to each other at the projection center of the projection optical system and the third measurement axis.
The two-dimensional position of the second substrate stage is measured by an interferometer of a length measuring axis, and the two-dimensional position of the second substrate stage is measured by an interferometer of a second measuring axis and a third measuring axis that intersect perpendicularly at the projection center. Is accurately measured without Abbe error.
In particular, since the first measurement axis and the second measurement axis are arranged in the above-described positional relationship, the measurement is performed while the first substrate stage and the second substrate stage are moved in the first axis direction. Since the long axis is not cut off, the two substrate stages can be reciprocated between the alignment system and the projection optical system based on the measurement values of these measurement axes by the interferometer. While the stage is under the alignment system, the second substrate stage can be positioned under the projection optical system, and the position detection operation of the mark on the respective substrate stage or the sensitive substrate by the alignment system can be performed. The exposure operation by the optical system can be performed in parallel, and as a result, the throughput can be improved.

In this case, the alignment system may be provided with at least one alignment system separately from the projection optical system. However, as in the second aspect of the present invention, the two alignment systems (24a, 24b) are projected. The optical system (PL) may be arranged on one side and the other side in the first axis direction with the optical system (PL) interposed therebetween. When the alignment system is arranged in such a positional relationship, while the sensitive substrate on one substrate stage is exposed by the projection optical system located at the center (exposure operation), the sensitive substrate on the other substrate stage is exposed. Can be detected using any of the alignment systems (alignment operation). When switching between the exposure operation and the alignment operation, the substrate stage on which the alignment operation has been completed can be moved below the projection optical system by simply shifting the two substrate stages in the first axis direction. The substrate stage can be moved to the position of the alignment system.

In this case, as in the third aspect of the present invention,
First substrate stage and second substrate stage (WS1 and W
In step S2), an interferometer system (for example, a length measuring axis B) is used so that an exposure operation by the projection optical system (PL) and a mark detection operation by the alignment system (for example, 24a) can be performed.
Control means (90) for independently controlling the movement of the first substrate stage and the second substrate stage based on the measurement results of I1X to BI4Y) may be further provided. According to this, the control means controls the interferometer system so that each of the first substrate stage and the second substrate stage can perform the exposure operation by the projection optical system (PL) and the mark detection operation by the alignment system (for example, 24a). (For example, measuring axis BI1
X to BI4Y), the movement of the first substrate stage and the movement of the second substrate stage are independently controlled based on the measurement results. And the mark detection operation can be performed reliably.

In this case, if the distance between the length measurement axes BI3Y and BI4Y is too large, the length measurement axes BI3Y and BI4Y are displaced from the substrate stage when the first and second substrate stages move. If the control means (9) does not cause the interference between the two stages, the control means (9
0) are a first substrate stage and a second substrate stage (WS
1 and WS2) when the mark is detected by the alignment system (for example, 24a) and when the projection optical system (P
L) and at the time of exposure by the interferometer system (for example, the measurement axis B
It is desirable that the third measurement axis (BI3Y) and the fourth measurement axis (BI4Y) of I1X to BI4Y be switched so that the substrate stage may be displaced from the measurement axis.

In this case, the third measurement axis (B
I3Y) and the fourth measurement axis (BI4Y) can be widened to prevent interference between the two stages, and when the first substrate stage and the second substrate stage are moved, the measurement axis BI3Y is used. , BI4Y deviate from the substrate stage, the control means switches the length measurement axes, so that the two-dimensional position of each substrate stage at each processing position can be accurately measured using the interferometer system.

According to a fifth aspect of the present invention, there is provided a projection exposure apparatus for projecting and exposing an image of a pattern formed on a mask (R) onto a sensitive substrate (W1, W2) via a projection optical system (PL). A first substrate stage (WS1) that can move in a two-dimensional plane while holding the sensitive substrate (W1); and a first substrate stage (WS1) that holds the sensitive substrate (W2) and moves in the same plane as the first substrate stage (WS1). A second substrate stage (WS2) movable independently of the first substrate stage (WS1); provided separately from the projection optical system (PL), on the substrate stage (WS1, WS2) or on the substrate stage (WS1,
At least one alignment system (for example, 24a) for detecting a mark on the sensitive substrate (W1, W2) held by the second substrate stage (WS2); the first substrate stage (WS1) and the second
One of the substrate stages (WS2) (WS1)
Or WS2) performs the mark detection operation by the alignment system (24a) while the other stage (WS2 or WS1) performs the exposure operation so that both stages (WS1, WS2) perform the exposure operation.
And a control means (90) for controlling the operation of WS2).

According to this, both the first and second substrate stages are controlled by the control means such that while one of the first and second substrate stages performs the mark detection operation by the alignment system, the other stage performs the exposure operation. (WS1,
Since the operation of WS2) is controlled, the mark detection operation on the sensitive substrate held on one substrate stage and the exposure operation of the sensitive substrate held on the other substrate stage can be performed in parallel. . Therefore, since the operations at the time T2 and the time T3 described above and the operation at the time T4 can be performed in parallel, it is possible to improve the throughput as compared with the conventional sequential processing that required the time (T1 + T2 + T3 + T4). become.

In this case, the first substrate stage and the second substrate stage (WS)
1 and WS2) and the transfer system (180 to 200) for transferring the sensitive substrate (W1, W2), the control means (90) determines that the one substrate stage (WS1 or WS2) is Transport system (180
To 200) and the transfer of the sensitive substrate and the mark detection operation by the alignment system (24a), so that the other substrate stage (WS2 or WS1) performs the exposure operation by the projection optical system (PL). Stage (W
It is more desirable to control the operation of S1, WS2). In this case, the operations at time T1, time T2, and time T3 described above can be performed on one substrate stage, and the operation at time T4 can be performed on the other substrate stage. The throughput can be further improved as compared with the case of the invention described in (5).

According to the fifth aspect of the present invention, at least one alignment system may be provided separately from the projection optical system. As in the invention described in Item 7, two alignment systems (24a, 24b) are disposed on both sides of the projection optical system (PL) along a predetermined direction, respectively.
The control means (90) includes a first substrate stage (WS1)
The mark on the sensitive substrate (W1) held on the first substrate stage (WS1) or on the first substrate stage (WS1) is aligned with one of the alignment systems (24).
a) on the second substrate stage (WS2) or on the second
Sensitive substrate (W2) held on substrate stage (WS2)
The upper mark may be detected by the other alignment system (24b).

In this case, while the sensitive substrate on one substrate stage is being exposed by the projection optical system located at the center (exposure operation), the sensitive substrate on the other substrate stage is exposed to the other substrate stage. In the case where mark detection is performed using an alignment system (alignment operation) and switching between the exposure operation and the alignment operation is performed, the projection optical system is simply moved by moving the two substrate stages along the predetermined direction toward the other alignment system. It is possible to easily move one substrate stage under the system to the other alignment system position and move the other substrate stage at one alignment system position to under the projection optical system, In this way, two alignment systems can be used alternately.

An eighth aspect of the present invention is a projection exposure apparatus for projecting and exposing an image of a pattern formed on a mask (R) onto a sensitive substrate (W1, W2) via a projection optical system (PL). And a first substrate stage (WS1) holding a sensitive substrate (W1) and movable in a two-dimensional plane; and a first substrate stage (WS1) holding a sensitive substrate (WS2).
A second substrate stage (WS2) movable independently of the first substrate stage (WS1) in the same plane as the first substrate stage and the second substrate stage (WS1, WS1).
2) and a transfer system for transferring the sensitive substrate (180)
To 200); and while one of the first substrate stage (WS1) and the second substrate stage (WS2) transfers the sensitive substrate to and from the transport system (180 to 200), the other stage is Control means (90) for controlling the operation of both stages so as to perform an exposure operation.

According to this, while one of the first substrate stage and the second substrate stage transfers the sensitive substrate to and from the transfer system by the control means, the other stage performs the exposure operation. Thus, the operations of both stages are controlled. Therefore, the operation at the time T1 and the operation at the time T4 described above can be processed in parallel.
(1 + T2 + T3 + T4), it is possible to improve the throughput as compared with the conventional sequential processing that required (1 + T2 + T3 + T4).

In the projection exposure apparatus according to each of the above aspects, it is sufficient if the exposure can be performed using one mask, but as in the ninth aspect of the present invention, a mask stage capable of mounting a plurality of masks (R) simultaneously. (RST); and a drive system (30) for driving the mask stage (RST) such that one of the plurality of masks (R) is selectively set at the exposure position. According to this, for example, in order to improve resolution, even if the two masks are switched by the so-called double exposure method and the overprinting is performed under the appropriate exposure conditions for each exposure area, the mask stage is set in advance. A single mask is mounted, and this is switched to the exposure position by the drive system. During continuous double exposure using two masks on one of the substrate stages, this is performed in parallel. Other operations, such as alignment, can be performed on the other substrate stage side, thereby significantly improving low throughput by the double exposure method.

The projection exposure apparatus of each of the above-mentioned inventions is better than a stationary projection exposure apparatus such as a stepper that projects and exposes a pattern of a mask onto a sensitive substrate via a projection optical system while the mask and the sensitive substrate are stationary. The mask (R) is mounted on a mask stage (RST) movable in a predetermined direction, and the mask stage (R)
ST) and one of the first substrate stage and the second substrate stage (WS1 and WS2) are synchronously moved, and the mask pattern is moved to the sensitive substrate (WS).
Stage control means (3, 1) for projecting and exposing on WS2)
The scanning projection exposure apparatus further having 8) is more effective. That is, high-precision exposure can be realized by the averaging effect of the image in the projection area of the mask pattern by the projection optical system, and a smaller projection optical system is used as compared with a stationary projection exposure apparatus. This is because a larger area can be exposed.

The eleventh aspect of the present invention provides a mask (R)
Is a projection exposure method for projecting and exposing an image of a pattern formed on a sensitive substrate (W1, W2) via a projection optical system (PL), the two-dimensional plane holding the sensitive substrate (W1, W2). Two substrate stages (WS1, WS2) that can move independently of each other are prepared, and one of the two substrate stages (WS1, WS2) (WS1 or WS2) exchanges a sensitive substrate. During at least one of the operation of detecting a mark on the substrate stage or the mark on the sensitive substrate held by the substrate stage, the other stage (WS2 or W2) of the two substrate stages is performed.
In S1), the exposure operation for the sensitive substrate is performed.

According to this, while at least one of the operation at the time T1 and the operation at the time (T2 + T3) described above is performed on one substrate stage, the operation at the time T4 is concurrently performed with the other operation. Is performed on the substrate stage, it is possible to improve the throughput as compared with the conventional sequential processing that requires time (T1 + T2 + T3 + T4). In particular, when the operation of the time (T1 + T2 + T3) is performed on one stage while the operation of the time T4 is performed on the other stage in parallel with the operation, the throughput can be further improved. .

In this case, the respective operations performed on the two substrate stages are not always completed at the same time, but at the time when the respective operations of the two substrate stages are completed as in the invention according to the eleventh aspect. The operation of the two substrate stages may be switched. This allows
If the operation is completed earlier, the operation enters a standby state, and the operation is switched when the operation in both stages is completed. Since the standby time causes a reduction in throughput, it is desirable to divide the operation contents for performing the parallel processing on the two substrate stages so as to minimize the standby time.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

FIG. 1 shows a schematic configuration of a projection exposure apparatus 10 according to one embodiment. This projection exposure apparatus 10
Is a step-and-scan type scanning exposure type projection exposure apparatus.

The projection exposure apparatus 10 holds wafers W1 and W2 as sensitive substrates on the base board 12 and independently moves in two-dimensional directions on a wafer stage WS1 as first and second substrate stages. , WS2, a projection optical system PL disposed above the stage device, and a reticle R as a mask above the projection optical system PL mainly in a predetermined scanning direction, here a Y-axis direction (in FIG. 1). A reticle driving mechanism for driving the reticle R from above is provided, and a control system for controlling these components is provided.

The stage device is levitated and supported on a base plate 12 via an air bearing (not shown), and is independent in the X-axis direction (the horizontal direction in FIG. 1) and the Y-axis direction (the direction perpendicular to the paper plane in FIG. 1). It is provided with two wafer stages WS1 and WS2 that can be moved two-dimensionally, a stage drive system that drives these wafer stages WS1 and WS2, and an interferometer system that measures the positions of wafer stages WS1 and WS2.

More specifically, air pads (not shown) (for example, a vacuum preload type air bearing) are provided at a plurality of locations on the bottom surface of the wafer stages WS1 and WS2, and the air ejection force of the air pads and the vacuum preload are provided. It is floated and supported on the base plate 12 while maintaining a spacing of, for example, several microns by balance with pressure.

As shown in the plan view of FIG. 3, two X-axis linear guides extending in the X-axis direction (such as a stationary magnet of a so-called moving coil type linear motor) are provided on the base board 12. ) 122 and 124 are provided in parallel, and these X-axis linear guides 12
2 and 124 respectively include two moving members 114, 118 and 116, 1 that can move along the respective X-axis linear guides.
20 are attached respectively. On the bottom surface of these four moving members 114, 118, 116, 120, X
Driving coils (not shown) are attached so as to surround the axis linear guide 122 or 124 from above and from the side, respectively, and these moving coils and the X-axis linear guide 122 or 124 respectively move the moving members 114, 116, 11.
Moving coil type linear motors for driving the motors 8 and 120 in the X-axis direction are configured respectively. However, in the following description, for convenience, the moving members 114, 116, 1
18 and 120 are called X-axis linear motors.

Of these, two X-axis linear motors 114, 1
16 is a Y-axis linear guide extending in the Y-axis direction (for example,
Each of the two X-axis linear motors 118 and 120 is provided at both ends of a moving magnet type linear motor (such as a fixed side coil of a linear motor) 110, and Y
It is fixed to both ends of a similar Y-axis linear guide 112 extending in the axial direction. Therefore, the Y-axis linear guide 110
X-axis linear motors 114 and 116 are driven along X-axis linear guides 122 and 124, and Y-axis linear guides 112 are driven by X-axis linear motors 118 and 120 along X-axis linear guides 122 and 124. It has become.

On the other hand, on the bottom of wafer stage WS1,
A magnet (not shown) surrounding one of the Y-axis linear guides 110 from above and from the side is provided.
A moving magnet type linear motor that drives S1 in the Y-axis direction is configured. Also, the wafer stage W
A magnet (not shown) surrounding the other Y-axis linear guide 112 from above and from the side is provided at the bottom of S2, and the magnet and the Y-axis linear guide 112 drive the wafer stage WS2 in the Y-axis direction. A moving magnet type linear motor is configured.

That is, in the present embodiment, the X-axis linear guides 122 and 124 and the X-axis linear motor 11
4, 116, 118, 120, Y-axis linear guide 11
0, 112 and the wafer stages WS1, WS2 by magnets (not shown) at the bottom of the wafer stages WS1, WS2.
A stage drive system for independently driving XY two-dimensionally for S2 is configured. This stage drive system is controlled by the stage control device 38 of FIG.

By slightly changing the torque of the pair of X-axis linear motors 114 and 116 provided at both ends of the Y-axis linear guide 110, it is possible to generate or remove minute yawing on the wafer stage WS1. It is. Similarly, by slightly changing the torque of the pair of X-axis linear motors 118 and 120 provided at both ends of the Y-axis linear guide 112, it is possible to generate or remove minute yawing on the wafer stage WS2. .

The wafers W1 and W2 are fixed on the wafer stages WS1 and WS2 via a wafer holder (not shown) by vacuum suction or the like. The wafer holder is driven by a Z · θ drive mechanism (not shown) to
The actuator is minutely driven in the axial direction and the θ direction (rotational direction around the Z axis). Further, the wafer stage WS1,
On the upper surface of WS2, fiducial mark plates FM1 and FM2 on which various fiducial marks are formed are installed so as to be approximately the same height as wafers W1 and W2. These reference mark plates FM1 and FM2 are used, for example, when detecting the reference position of each wafer stage.

Further, a surface 20 on one side in the X-axis direction (left side surface in FIG. 1) 20 of wafer stage WS1 and a surface 21 on one side in the Y-axis direction (surface on the back side in FIG. 1) are mirror-finished. Similarly, a surface on the other side in the X-axis direction of wafer stage WS2 (right side surface in FIG. 1) 22
And the surface 23 on one side in the Y-axis direction are mirror-finished reflection surfaces. Each of these length measuring axes (BI1X, BI2X) constituting an interferometer system described later
), And the reflected light is received by each interferometer, so that a fixed mirror is arranged at the reference position of each reflecting surface (generally, the side of the projection optical system or the side of the alignment optical system, (This is used as a reference plane) to measure the two-dimensional positions of the wafer stages WS1 and WS2. In addition,
The configuration of the measurement axis of the interferometer system will be described later in detail.

As the projection optical system PL, here,
Consisting of a plurality of lens elements having a common optical axis in the Z-axis direction, a predetermined reduction magnification by telecentric on both sides,
For example, a refractive optical system having 1/5 is used. Therefore, the moving speed of the wafer stage in the scanning direction during the step-and-scan scanning exposure is 1/5 of the moving speed of the reticle stage.

As shown in FIG. 1, an off-axis type alignment system 24a, 24b having the same function is provided on both sides of the projection optical system PL in the X-axis direction.
Are located at the same distance from the optical axis center of the projection optical system PL (coincident with the projection center of the reticle pattern image). These alignment systems 24a,
4b is an LSA (Laser Step Alignment) system, FIA
(Filed Image Alignment) system, LIA (Laser Interf
It has three types of alignment sensors of the type (Erometric Alignment) system, and can measure the position of the reference mark on the reference mark plate and the alignment mark on the wafer in the X and Y two-dimensional directions.

Here, the LSA system is the most versatile sensor that irradiates a laser beam to a mark and measures the position of the mark by using diffracted and scattered light. Is done. The FIA system is a sensor that illuminates a mark with broadband (broadband) light such as a halogen lamp and measures the mark position by processing the mark image, and is used effectively for an asymmetric mark on an aluminum layer or a wafer surface. You. In addition, LIA system
A sensor that irradiates a diffraction grating mark with laser light whose frequency is slightly changed from two directions, interferes the two generated diffraction lights, and detects mark position information from its phase. Used effectively for rough wafers.

In the present embodiment, these three types of alignment sensors are properly used depending on the purpose, so-called search alignment for detecting the positions of three one-dimensional marks on the wafer and measuring the approximate position of the wafer, Fine alignment and the like for performing accurate position measurement of each shot area on the wafer are performed.

In this case, the alignment system 24a is used for position measurement of the alignment marks on the wafer W1 held on the wafer stage WS1 and the reference marks formed on the reference mark plate FM1. Further, the alignment system 24b includes an alignment mark and a reference mark plate FM on the wafer W2 held on the wafer stage WS2.
2 is used for measuring the position of a reference mark formed on the surface 2.

Information from each alignment sensor constituting these alignment systems 24a and 24b is A / D-converted by an alignment control device 80, and a digitized waveform signal is processed to detect a mark position.
The result is sent to the main controller 90, and the main controller 90 instructs the stage controller 38 to correct the synchronous position at the time of exposure according to the result.

Further, in the exposure apparatus 10 of the present embodiment,
Although not shown in FIG. 1, FIG.
A reticle R via a projection optical system PL as shown in FIG.
Upper reticle mark (not shown) and reference mark plate FM
1. A pair of reticle alignment microscopes 1 comprising a TTR (Through The Reticle) alignment optical system using an exposure wavelength for simultaneously observing marks on the FM 2
42 and 144 are provided. The detection signals of the reticle alignment microscopes 142 and 144 are supplied to the main controller 90. In this case, deflecting mirrors 146 and 148 for guiding the detection light from reticle R to reticle alignment microscopes 142 and 144 are movably arranged, and when the exposure sequence is started, a command from main controller 90 is also issued. Then, the deflection mirrors 146 and 148 are retracted by the mirror driving device (not shown). The reticle alignment microscope 14
2 and 144 are disclosed in, for example, Japanese Patent Application Laid-Open No. 7-1764.
Since it is disclosed in Japanese Patent Publication No. 68, the detailed description is omitted here.

Although not shown in FIG. 1, each of the projection optical system PL and the alignment systems 24a and 24b has an autofocus / autoleveling measurement for checking the in-focus position as shown in FIG. Mechanism (hereinafter,
130, 132, and 134 are provided. Among them, the AF / AL system 132 projects the pattern formation surface on the reticle R and the exposure surface of the wafer W to accurately transfer the pattern on the reticle R onto the wafer (W1 or W2) by scan exposure. Since it is necessary to be conjugate with respect to the optical system PL, it is detected whether or not the exposure surface of the wafer W matches the image plane of the projection optical system PL within the range of the depth of focus (whether or not in focus). It is provided in order to In the present embodiment, a so-called multipoint AF system is used as the AF / AL system 132.

Here, a detailed configuration of the multipoint AF system constituting the AF / AL system 132 will be described with reference to FIGS.

This AF / AL system (multipoint AF system) 132
As shown in FIG. 5, the optical fiber bundle 150, the condenser lens 152, the pattern forming plate 154, the lens 156,
It comprises an irradiation optical system 151 including a mirror 158 and an irradiation objective lens 160, and a condensing optical system 161 including a converging objective lens 162, a rotational direction diaphragm 164, an imaging lens 166, and a light receiver 168.

Here, the AF / AL system (multipoint AF system)
The components of the above-described configuration 132 will be described together with their operations.

The wafer W1 (or W) different from the exposure light EL
2) Illumination light having a wavelength that does not expose the upper photoresist is guided from an unillustrated illumination light source via an optical fiber bundle 150, and the illumination light emitted from the optical fiber bundle 150 passes through a condenser lens 152 to form a pattern. The forming plate 154 is illuminated. The illumination light transmitted through the pattern forming plate 154 is transmitted to the lens 156, the mirror 158, and the illumination objective lens 1
The wafer W1 is projected onto the exposure surface of the wafer W through
An image of the pattern on the pattern forming plate 154 is projected and formed obliquely to the optical axis AX on the exposure surface (or W2). The illumination light reflected by the wafer W1 is projected on the light receiving surface of the light receiver 168 via the condensing objective lens 162, the rotation direction vibration plate 164, and the imaging lens 166, and is projected onto the pattern forming plate 154 on the light receiving surface of the light receiver 168. Is re-imaged. Here, the main control device 90 includes a vibration device 172.
A predetermined vibration is applied to the rotation direction vibration plate 164 via the optical disk, and detection signals from a large number (specifically, the same number as the number of slit patterns of the pattern forming plate 154) of the light receiver 168 are sent to the signal processing device 170. Supply. In addition, the signal processing device 170 supplies a large number of focus signals obtained by synchronously detecting each detection signal with the drive signal of the vibration device 172 to the main control device 90 via the stage control device 38.

In this case, as shown in FIG. 6, for example, 5 × 9 = 45 vertical slit-shaped opening patterns 93-11 to 93-59 are formed on the pattern forming plate 154. Images of these slit-shaped opening patterns are projected on the exposure surface of the wafer W obliquely (45 °) with respect to the X axis and the Y axis. As a result, a slit image having a matrix arrangement inclined at 45 ° with respect to the X axis and the Y axis as shown in FIG. 4 is formed. The symbol IF in FIG. 4 indicates an illumination field on the wafer conjugate with an illumination area on the reticle illuminated by the illumination system. This figure 4
As is clear from FIG. 7, the detection beam is applied to an area two-dimensionally larger than the illumination field IF below the projection optical system PL.

Other AF / AL systems 130 and 134 also
It is configured similarly to the AF / AL system 132. That is, in the present embodiment, AF / AL mechanisms 130 and 13 used when measuring alignment marks cover substantially the same area as the AF / AL system 132 used for focus detection during exposure.
4 also allows the detection beam to be irradiated. Therefore, when measuring the alignment sensor by the alignment systems 24a and 24b, the same AF / A
By performing the position measurement of the alignment mark while performing the auto-focus / auto-leveling by the measurement and control of the L system, highly accurate alignment measurement can be performed. In other words, an offset (error) due to the posture of the stage does not occur between the time of exposure and the time of alignment.

Next, the reticle driving mechanism will be described with reference to FIGS.

The reticle driving mechanism includes a reticle stage RST that holds a reticle R on a reticle base board 32 and is movable in a two-dimensional XY direction, a linear motor (not shown) that drives the reticle stage RST, A reticle interferometer system for managing the position of the reticle stage RST.

More specifically, as shown in FIG. 2, reticle stage RST includes two reticle Rs.
1, reticle stage RST can be installed in series in the scanning direction (Y-axis direction).
2, a fine drive in the X-axis direction by a drive mechanism 30 (see FIG. 1),
Micro rotation in the θ direction and scanning driving in the Y axis direction are performed. The drive mechanism 30 is a mechanism using a linear motor as a drive source similar to the stage device described above, but is shown as a simple block in FIG. 1 for convenience of illustration and description. For this reason, the reticles R1 and R2 on the reticle stage RST are selectively used, for example, in the case of double exposure, and any of the reticles can be synchronously scanned with the wafer side.

On the reticle stage RST, a parallel plate moving mirror 34 made of the same material (for example, ceramic) as the reticle stage RST is provided at the other end in the X-axis direction.
Are extended in the Y-axis direction, and a reflection surface is formed on the other surface of the movable mirror 34 in the X-axis direction by mirror finishing. The interferometer beam from the interferometer 36 indicated by the measurement axis BI6X is irradiated toward the reflecting surface of the movable mirror 34, and the interferometer receives the reflected light and receives the reflected light with respect to the reference surface in the same manner as the wafer stage. By measuring the relative displacement, the position of reticle stage RST is measured. Here, the interferometer having the measurement axis BI6X actually has two interferometer optical axes that can be measured independently, and measures the position of the reticle stage in the X-axis direction and the measurement of the yawing amount. Is possible. The measurement value of the interferometer having the length measurement axis BI6X is measured by the length measurement axis BI1 on the wafer stage side.
The reticle stage RST is controlled to rotate in a direction to cancel the relative rotation (rotation error) between the reticle and the wafer based on the yawing information and the X position information of the wafer stages WS1 and WS2 from the interferometers 16 and 18 having X and BI2X. , X-direction synchronization control.

On the other hand, on the other side in the Y-axis direction (scanning direction) of reticle stage RST (on the front side in FIG. 1), a pair of corner cube mirrors 3 are provided.
5, 37 are installed. Then, a pair of double-pass interferometers (not shown) irradiate these corner cube mirrors 35 and 37 with interferometer beams indicated by measurement length axes BI7Y and BI8Y in FIG.
The reflected light is returned from the corner cube mirrors 35 and 37 to the reflection surface on the second 2, and each reflected light reflected there returns along the same optical path and is received by each double-pass interferometer, and the reference position of each corner cube mirror 35 and 37 ( At the reference position, the relative displacement from the reflection surface on the reticle base plate 32) is measured. Then, the measured values of these double-pass interferometers are converted to the stage controller 38 of FIG.
And a reticle stage R based on the average value.
The position of ST in the Y-axis direction is measured. This information on the Y-axis direction position is calculated by calculating the relative position between the reticle stage RST and the wafer stage WS1 or WS2 based on the measurement value of the interferometer having the wafer-side measurement axis BI3Y, and performing scanning at the time of scanning exposure based on this. It is used for synchronous control of the reticle in the direction (Y-axis direction) and the wafer.

That is, in the present embodiment, a reticle interferometer system is constituted by the interferometer 36 and a pair of double-pass interferometers indicated by the measurement axes BI7Y and BI8Y.

Next, wafer stages WST1, WST2
An interferometer system that manages the position of the image will be described with reference to FIGS.

As shown in these figures, the X-axis direction of wafer stage WS1 along the first axis (X-axis) passing through the projection center of projection optical system PL and the detection centers of alignment systems 24a and 24b. One surface is irradiated with an interferometer beam indicated by a first measurement axis BI1X from the interferometer 16 in FIG. 1, and the wafer stage W is similarly moved along the first axis.
The other surface in the X-axis direction of S2 is irradiated with an interferometer beam indicated by a second measurement axis BI2X from the interferometer 18 in FIG. Then, the interferometers 16 and 18 measure the relative displacement of each reflecting surface from the reference position by receiving these reflected lights, and measure the positions of the wafer stages WS1 and WS2 in the X-axis direction. . Here, as shown in FIG. 2, the interferometers 16 and 18 are three-axis interferometers each having three optical axes, and the wafer stages WS1 and WS
In addition to the measurement in the X-axis direction of 2, the tilt measurement and the θ measurement can be performed. The output value of each optical axis can be measured independently. Here, wafer stages WS1, WS2
Stage (not shown) for performing the θ rotation and Z-leveling stage (not shown) for performing the minute drive and the tilt drive in the Z-axis direction are actually located below the reflecting surface. The amount of drive is all
6 and 18 can be monitored.

The first measuring axis BI1X and the second measuring axis B
Each of the I2X interferometer beams is connected to a wafer stage WS1, W2
Wafer stages WS1 and W are always in the entire movement range of S2.
Therefore, in the X-axis direction, the positions of the wafer stages WS1 and WS2 are set to the first position at any time such as at the time of exposure using the projection optical system PL and at the time of using the alignment systems 24a and 24b. 1 measurement axis BI1X,
It is managed based on the measurement value of the second length measurement axis BI2X.

As shown in FIGS. 2 and 3, an interferometer having a third measurement axis BI3Y perpendicular to the first axis (X axis) at the projection center of the projection optical system PL, and an alignment system At the detection center of each of 24a and 24b, the first axis (X
), And interferometers each having a length measurement axis BI4Y, BI5Y as a fourth length measurement axis, which intersects each other vertically (however, only the length measurement axis is shown in the drawing).

In the case of the present embodiment, the position measurement in the Y direction of the wafer stages WS1 and WS2 at the time of exposure using the projection optical system PL requires the projection center of the projection optical system, that is, the length measurement axis BI3Y passing through the optical axis AX. Of the interferometer of
Wafer stage WS1 when using alignment system 24a
In the Y direction position measurement, the measurement value of the detection center of the alignment system 24a, that is, the interferometer measurement of the length measurement axis BI4Y passing through the optical axis SX is used, and the Y direction position measurement of the wafer stage WS2 when the alignment system 24b is used. The measurement value of the detection center of the alignment system 24b, that is, the measurement value of the interferometer of the length measurement axis BI5Y passing through the optical axis SX is used.

Therefore, depending on each use condition, the long axis of the interference measurement in the Y-axis direction deviates from the reflection surface of the wafer stage WS1, WS2, but at least one of the long measurement axes, ie, the long measurement axes BI1X, BI2X, Of the wafer stages WS1 and WS2,
At an appropriate position where the optical axis of the interferometer to be used is on the reflecting surface,
The reset of the interferometer on the side can be performed. The method of resetting the interferometer will be described later in detail.

Note that the length measurement axes BI3Y and B
Each of the interferometers I4Y and BI5Y is a two-axis interferometer having two optical axes, and the Y-interferometers of the wafer stages WS1 and WS2.
In addition to the axial measurement, tilt measurement is possible.
The output value of each optical axis can be measured independently

In this embodiment, the wafer stage WS is controlled by a total of five interferometers including interferometers 16 and 18 and three interferometers having length measuring axes BI3Y, BI4Y and BI5Y.
1. An interferometer system that manages the two-dimensional coordinate position of WS2 is configured.

In this embodiment, as described later,
While one of the wafer stages WS1 and WS2 is performing the exposure sequence, the other is performing the wafer exchange and the wafer alignment sequence. At this time, the output value of each interferometer is set so that there is no interference between the two stages. The movement of the wafer stages WS1 and WS2 is managed by the stage controller 38 in response to a command from the main controller 90 based on the above.

Next, the illumination system will be described with reference to FIG. As shown in FIG. 1, the illumination system includes a light source unit 40, a shutter 42, a mirror 44, beam expanders 46 and 48, a first fly-eye lens 50, a lens 52,
Vibrating mirror 54, lens 56, second fly-eye lens 5
8, a lens 60, a fixed blind 62, a movable blind 64, relay lenses 66 and 68, and the like.

Here, the components of the illumination system will be described together with their operations.

A laser beam emitted from a light source section 40 comprising a KrF excimer laser as a light source and a dimming system (a dimming plate, an aperture stop, etc.) passes through a shutter 42, is deflected by a mirror 44, and is beam extracted Panda 46,
The beam is shaped into an appropriate beam diameter by 48 and is incident on the first fly-eye lens 50. This first fly-eye lens 5
The luminous flux incident on the first fly-eye lens is divided into a plurality of luminous fluxes by two-dimensionally arranged fly-eye lens elements. The light enters the lens 58. The light beam emitted from the second fly-eye lens 58 reaches the fixed blind 62 installed at a position conjugate with the reticle R by the lens 60, where the cross-sectional shape is defined to a predetermined shape. A predetermined shape defined by the fixed blind 62 on the reticle R as uniform illumination light passing through the movable blind 64 disposed at a position slightly defocused from the conjugate plane of the reticle R, through the relay lenses 66 and 68, Here, a rectangular slit-shaped illumination area IA (see FIG. 2) is illuminated.

Next, the control system will be described with reference to FIG. This control system mainly includes a main controller 90 that controls the entire apparatus as a whole, and includes an exposure controller 70, a stage controller 38, and the like under the main controller 90.

Here, the operation of the projection exposure apparatus 10 according to the present embodiment at the time of exposure will be described focusing on the operation of each component of the control system.

Prior to the start of the synchronous scanning of the reticle R and the wafer (W1 or W2), the exposure controller 70 instructs the shutter driver 72 to drive the shutter driver 74 to drive the shutter 42. To open.

Thereafter, the reticle R and the wafer (W1) are controlled by the stage controller 38 according to the instruction of the main controller 90.
Or W2), that is, synchronous scanning (scan control) of the reticle stage RST and the wafer stage (WS1 or WS2) is started. This synchronous scanning is performed by measuring the measurement axis BI3Y and the measurement axis BI1X or BI2X of the interferometer system described above.
Measuring axis BI7Y, BI8 of reticle interferometer system
The monitoring is performed by controlling the reticle driving unit 30 and each linear motor constituting the drive system of the wafer stage by the stage controller 38 while monitoring the measured values of Y and the measurement axis BI6X.

Then, when both stages are controlled at a constant speed within a predetermined allowable error, the exposure control device 70
Instruct the laser control unit 76 to start pulse emission. As a result, the illumination light from the illumination system illuminates the rectangular illumination area IA of the reticle R on which the pattern is chromium-deposited on the lower surface, and the image of the pattern in the illumination area is reduced by the projection optical system PL to 1/5 Wafer (W1 or W1)
2) Projection exposure on top. Here, as is clear from FIG. 2, the illumination area IA is compared with the pattern area on the reticle.
The width of the slit in the scanning direction is narrow, and by synchronously scanning the reticle R and the wafer (W1 or W2) as described above,
An image of the entire surface of the pattern is sequentially formed in a shot area on the wafer.

At the same time as the start of the above-described pulse emission, the exposure control unit 70 instructs the mirror driving unit 78 to drive the vibration mirror 54 so that the pattern area on the reticle R is completely illuminated by the illumination area IA ( 2), that is, until an image of the entire surface of the pattern is formed in the shot area on the wafer, the interference fringes generated by the two fly-eye lenses 50 and 58 are continuously performed. Reduce unevenness.

The movable blind 64 is controlled in synchronization with the scanning of the reticle R and the wafer W so that the illumination light does not leak outside the light-shielding area on the reticle at the shot edge during the scanning exposure. The drive is controlled by a device 39, and a series of these synchronous operations are managed by a stage control device 38.

In the pulse emission by the laser controller 76, it is necessary to emit light n times (n is a positive integer) while an arbitrary point on the wafers W1 and W2 passes through the illumination field width (w). Therefore, if the oscillation frequency is f and the wafer scan speed is V, the following equation (2) must be satisfied.

F / n = V / w (2) When the irradiation energy of one pulse irradiated on the wafer is P and the resist sensitivity is E, the following equation (3) is satisfied. There is a need.

NP = E (3) As described above, the exposure control device 70 sets the irradiation energy P
And the variable amount of the oscillation frequency f, and issues a command to the laser control device 76 to control the dimming system provided in the light source unit 40 to change the irradiation energy P and the oscillation frequency f. And the shutter driving device 72 and the mirror driving device 78 are controlled.

Further, when correcting the movement start position (synchronous position) of the reticle stage and the wafer stage for performing synchronous scanning during scan exposure, for example, the main controller 90 controls the stage controller 38 for controlling the movement of each stage. To instruct the correction of the stage position according to the correction amount.

Further, in the projection exposure apparatus of this embodiment, a first transfer system for exchanging wafers with wafer stage WS1 and a second transfer system for exchanging wafers with wafer stage WS2 are provided. Is provided.

As shown in FIG. 7, the first transfer system exchanges wafers with the wafer stage WS1 at the wafer loading position on the left side, as will be described later. The first transport system includes a first transport system extending in the Y-axis direction.
Loading guide 182, a first slider 186 moving along the loading guide 182, and a second slider 182.
Slider 190, the first unload arm 184 attached to the first slider 186, the second slider 1
90, a first wafer loader including a first load arm 188 and the like, and a first center-up 180 including three vertically moving members provided on the wafer stage WS1. You.

Here, the operation of wafer exchange by the first transfer system will be briefly described.

Here, as shown in FIG. 7, a case where wafer W1 'on wafer stage WS1 at the wafer loading position on the left and wafer W1 carried by the first wafer loader are exchanged will be described. I do.

First, main controller 90 turns off the vacuum of the wafer holder (not shown) on wafer stage WS1 via a switch (not shown), and releases the suction of wafer W1 '.

Next, main controller 90 drives center-up 180 up by a predetermined amount via a center-up drive system (not shown). Thereby, the wafer W1 'is lifted to a predetermined position. In this state, main controller 90 instructs a wafer loader controller (not shown) to move first unload arm 184. As a result, the first slider 186 is driven and controlled by the wafer loader control device, and the first unload arm 184 moves along the loading guide 182 to a position above the wafer stage WS1 and is located immediately below the wafer W1 ′.

In this state, main controller 90 drives center-up 180 downward to a predetermined position. Since the wafer W1 'is transferred to the first unload arm 184 during the lowering of the center-up 180, the main controller 90 instructs the wafer loader controller to start vacuuming the first unload arm 184. As a result, the wafer W1 'is suction-held by the first unload arm 184.

Next, main controller 90 causes wafer unloader controller to retract first unload arm 184, and
Of the load arm 188 is started. Accordingly, the first unload arm 184 starts moving in the -Y direction in FIG. 7 integrally with the first slider 186, and at the same time, the second slider 190 and the first load arm 188 holding the wafer W1 Movement is integrally started in the + Y direction. When the first load arm 188 comes above the wafer stage WS1, the wafer loader control unit stops the second slider 190 and releases the vacuum of the first load arm 188.

In this state, main controller 90 drives center-up 180 upward to cause wafer W1 to be lifted from below by center-up 180. Next, the main controller 90 instructs the wafer loader controller to retract the load arm. Thus, the second slider 190 starts moving in the −Y direction integrally with the first load arm 188, and the first load arm 188 is retracted.
At the same time that the first load arm 188 starts retreating, main controller 90 starts lowering drive of center-up 180 to place wafer W1 on a wafer holder (not shown) on wafer stage WS1, and reduces the vacuum of the wafer holder. turn on. Thus, a series of wafer exchange sequences is completed.

Similarly, as shown in FIG. 8, the second transfer system exchanges wafers with wafer stage WS2 at the right wafer loading position in the same manner as described above. The second transport system includes a second loading guide 192 extending in the Y-axis direction, and a third slider 1 moving along the second loading guide 192.
96, the fourth slider 200, and the third slider 196
Second unload arm 194 attached to the fourth, fourth
A second wafer loader including a second load arm 198 and the like attached to the slider 200, and a second center-up (not shown) provided on the wafer stage WS2.

Next, the parallel processing by two wafer stages, which is a feature of this embodiment, will be described with reference to FIGS.

In FIG. 7, while the wafer W2 on the wafer stage WS2 is being exposed via the projection optical system PL, the wafer stage WS1 and the first transfer are carried out as described above at the left loading position. FIG. 3 is a plan view showing a state where a wafer is exchanged with the system. In this case, on wafer stage WS1, an alignment operation is performed following the wafer exchange as described later. In FIG. 7, the position of the wafer stage WS2 during the exposure operation is controlled by the length measurement axis BI2 of the interferometer system.
The position control of the wafer stage WS1, which is performed based on the measured values of X and BI3Y and in which the wafer exchange and the alignment operation are performed, is performed by measuring the length measurement axes BI1X and BI4Y of the interferometer system.
This is performed based on the measured value of.

At the left loading position shown in FIG. 7, the wafer stage W is positioned immediately below the alignment system 24a.
The arrangement is such that the reference mark on the reference mark plate FM1 of S1 comes. Therefore, in main controller 90, before measuring the reference mark on reference mark plate FM1 by alignment system 24a, length measurement axis BI of the interferometer system is measured.
The 4Y interferometer is reset.

Subsequent to the above-described wafer exchange and resetting of the interferometer, search alignment is performed. The search alignment performed after the wafer exchange is the wafer alignment
Since the positional error is large only by the pre-alignment performed during the transfer of No. 1, the pre-alignment is performed again on the wafer stage WS1. Specifically, the positions of three search alignment marks (not shown) formed on wafer W1 mounted on stage WS1 are measured using an LSA-based sensor or the like of alignment system 24a, and the measurement is performed. Based on the result, the wafer W1 is aligned in the X, Y, and θ directions. The operation of each unit during the search alignment is controlled by main controller 90.

After the completion of the search alignment, fine alignment for obtaining the arrangement of each shot area on the wafer W1 using EGA is performed here. Specifically, while controlling the position of the wafer stage WS1 by the interferometer system (length measuring axes BI1X, BI4Y), the wafer stage WS1 is sequentially moved based on the designed shot array data (alignment mark position data). While moving, the alignment mark position of a predetermined sample shot on the wafer W1 is measured by an FIA sensor or the like of the alignment system 24a, and a statistical calculation by the least square method is performed based on the measurement result and the design coordinate data of the shot array. ,
Compute all shot array data. This EG
The operation of each part at the time of A is controlled by the main controller 90,
The above calculation is performed by main controller 90. It is desirable that the result of this operation be converted into a coordinate system based on the reference mark position of the reference mark plate FM1.

In the case of the present embodiment, as described above, the same AF / AF as during exposure is performed during measurement by the alignment system 24a.
The position of the alignment mark is measured while performing autofocus / autoleveling by the measurement and control of the AL system 132 (see FIG. 4), and an offset (error) due to the posture of the stage occurs between the alignment and the exposure. Can be prevented.

While the above-mentioned wafer exchange and alignment operations are being performed on the wafer stage WS1 side, the exposure conditions are adjusted on the wafer stage WS2 side using two reticles R1 and R2 as shown in FIG. Double exposure is performed continuously by the step-and-scan method while changing.

More specifically, fine alignment by EGA is performed in advance in the same manner as the wafer W1 described above, and the shot arrangement data on the wafer W2 obtained as a result (the reference alignment on the reference mark plate FM2) is obtained. After the shot areas on the wafer W2 are sequentially moved below the optical axis of the projection optical system PL on the basis of the mark, the reticle stage RST and the wafer stage WS2 are scanned each time each shot area is exposed. Scanning exposure is performed by synchronously scanning in the directions. Exposure to all shot areas on the wafer W2 is performed continuously even after reticle replacement. As a specific exposure sequence of the double exposure, as shown in FIG. 10A, each shot area of the wafer W1 is set to A1 using a reticle R2 (A pattern).
To A12, the drive system 30
After the reticle stage RST is moved by a predetermined amount in the scanning direction by using to set the reticle R1 (pattern B) to the exposure position, scan exposure is performed in the order of B1 to B12 shown in FIG. At this time, reticle R2 and reticle R
In Example 1, since the exposure conditions (AF / AL, exposure amount) and transmittance are different, it is necessary to measure each condition at the time of reticle alignment and change the condition according to the result.

The operation of each part of the wafer W2 during the double exposure is also controlled by the main controller 90.

In the exposure sequence and the wafer exchange / alignment sequence performed in parallel on the two wafer stages WS1 and WS2 shown in FIG. 7, the previously completed wafer stage is in a waiting state, and both operations are performed. Is completed, the wafer stage WS is moved to the position shown in FIG.
1. The movement of WS2 is controlled. The wafer W2 on the wafer stage WS2 for which the exposure sequence has been completed is replaced at the right loading position, and the wafer W1 on the wafer stage WS1 for which the alignment sequence has been completed is subjected to the exposure sequence under the projection optical system PL. Will be

In the right loading position shown in FIG. 8, the reference mark on the reference mark plate FM2 is arranged below the alignment system 24b, similarly to the left loading position. Will be executed. Of course, the reset operation of the interferometer of the length measuring axis BI5Y of the interferometer system is performed by the reference mark plate F by the alignment system 24b.
This is executed prior to the detection of the mark on M2.

Next, the reset operation of the interferometer by main controller 90 when shifting from the state of FIG. 7 to the state of FIG. 8 will be described.

After performing alignment at the left loading position, wafer stage WS1 is moved to a position where a reference mark on reference plate FM1 comes just below the center of optical axis AX (projection center) of projection optical system PL shown in FIG. Although the wafer stage is moved, the interferometer beam of the length measurement axis BI4Y is not incident on the reflection surface 21 of the wafer stage WS1 during the movement. Therefore, it is difficult to move the wafer stage to the position shown in FIG. It is. Therefore, in the present embodiment, the following measures are taken.

That is, as described above, in the present embodiment, when the wafer stage WS1 is located at the left loading position, the fiducial mark plate FM1 is set immediately below the alignment system 24a. Is reset, the wafer stage WS1 is once returned to this position, and the detection center of the alignment system 24a and the optical axis center (projection center) of the projection optical system PL are known from that position. ), The wafer stage WS1 is moved by the distance BL to the right in the X-axis direction while monitoring the measured value of the interferometer 16 on the length measuring axis BI1X where the interferometer beam does not break based on the distance (referred to as BL for convenience). Move. Thus, wafer stage WS1 is moved to the position shown in FIG. Main controller 90 uses at least one of reticle alignment microscopes 142 and 144 to measure the interferometer of measurement axis BI3Y prior to measuring the relative positional relationship between the mark on reference mark plate FM1 and the reticle mark. Reset. This reset operation can be executed when the next measurement axis can be irradiated on the side surface of the wafer stage.

As described above, the reason why high-precision alignment is possible even when the interferometer reset operation is performed is that after measuring the reference mark on the reference mark plate FM1 by the alignment system 24a, each shot area on the wafer W1 is measured. This is because the distance between the reference mark and the virtual position calculated by measuring the wafer mark is calculated by the same sensor by measuring the alignment mark. At this point, since the relative distance between the reference mark and the position to be exposed has been determined, the reticle alignment microscope 14 is required before exposure.
If the correspondence between the exposure position and the reference mark position is established by 2, 144, the interferometer beam of the interferometer in the Y-axis direction is cut off during the movement of the wafer stage by adding the relative distance to the value. Even if the reset is performed, a highly accurate exposure operation can be performed.

While the wafer stage WS1 moves from the alignment end position to the position shown in FIG.
If 4Y cannot be cut, the measurement axes BI1X, BI1X
It goes without saying that the wafer stage may be linearly moved to the position shown in FIG. 8 immediately after the completion of the alignment while monitoring the measured value of 4Y. In this case, the projection optical system PL is placed on the reflecting surface 21 orthogonal to the Y axis of the wafer stage WS1.
The interferometer may be reset when the length measurement axis BI3Y passing through the optical axis AX is applied.

In the same manner as above, the wafer stage WS2 may be moved from the exposure end position to the right loading position shown in FIG. 8, and the interferometer of the length measurement axis BI5Y may be reset.

FIG. 11 shows wafer stage WS1.
An example of the timing of an exposure sequence for sequentially exposing each shot area on the wafer W1 held thereon is shown in FIG. 12. FIG. 12 shows the wafer W2 held on the wafer stage WS2 performed in parallel with this. The timing of the alignment sequence above is shown. In the present embodiment, the two wafer stages WS1 and WS2 are independently
By performing the exposure sequence and the wafer exchange / alignment sequence on the wafers W1 and W2 on each wafer stage in parallel while moving in the dimensional direction, the throughput is improved.

However, when two operations are simultaneously performed in parallel using two wafer stages, the operation performed on one wafer stage may affect the operation performed on the other wafer stage as a disturbance factor. There is.
Conversely, there is also an operation in which an operation performed on one wafer stage does not affect an operation performed on the other wafer stage. Accordingly, in the present embodiment, of the operations to be performed in parallel, the operations that are not the causes of the disturbance are divided into the operations that are not the causes of the disturbance. Is adjusted.

For example, during scan exposure, since the wafer W1 and the reticle R are synchronously scanned at a constant speed, they do not become a disturbance factor, and it is necessary to eliminate other disturbance factors as much as possible. Therefore, during scan exposure on one wafer stage WS1, the timing is adjusted so that the alignment sequence performed on wafer W2 on the other wafer stage WS2 becomes stationary. That is, since the mark measurement in the alignment sequence is performed in a state where the wafer stage WS2 is stationary at the mark position, the mark measurement does not become a disturbance factor for scan exposure.
Mark measurement can be performed in parallel during scan exposure. 11 and 12, the operation numbers "1, 3, 5, 7, 9, 1, 1" are assigned to the wafer W1 in FIG.
12, 13, 15, 17, 19, 21, 23 "and the operation numbers" 1, 3, 5, 7, 9, 11, 13, 15, 17,.
19, 21, and 23, the mark measurement operations at the respective alignment mark positions are performed in synchronization with each other. On the other hand, also in the alignment sequence, high-precision measurement can be performed during scan exposure because the movement is constant speed and no disturbance occurs.

The same can be considered at the time of wafer exchange. In particular, vibration or the like generated when the wafer is transferred from the load arm to the center up position can be a disturbance factor. Therefore, acceleration or deceleration before or after scan exposure or before or after synchronous scanning is performed at a constant speed (disturbance factor) The transfer of the wafer may be performed according to the following.

The above-described timing adjustment is performed by the main controller 9.
Performed by 0.

As described above, according to the projection exposure apparatus 10 of the present embodiment, there are provided two wafer stages for independently holding two wafers, and these two wafer stages are independently moved in the XYZ directions. Then, while performing the wafer exchange and alignment operation on one wafer stage, the exposure operation was performed on the other wafer stage, and the operation was switched between each other when both operations were completed. Thus, the throughput can be greatly improved.

Further, according to the above-described embodiment, since at least two alignment systems for performing mark detection with the projection optical system PL interposed are provided, the two wafer stages are alternately shifted to alternately align each alignment system. It is possible to perform an alignment operation and an exposure operation, which are performed in the same manner, in parallel.

In addition, according to the above embodiment, the wafer loader for exchanging wafers is located near the alignment system,
Since the arrangement is such that the alignment can be performed at each alignment position, the transition from the wafer exchange to the alignment sequence is performed smoothly, and higher throughput can be obtained.

Further, according to the above-described embodiment, since the above-described high throughput can be obtained, even if the off-axis alignment system is set far away from the projection optical system PL, the influence of the deterioration of the throughput is almost eliminated. For this reason, high N.I. A. It is possible to design and install a straight-tube optical system having a small numerical aperture and a small aberration.

According to the above embodiment, each optical system has an interferometer beam from an interferometer that measures approximately the center of each optical axis of the two alignment systems and the projection optical system PL. In both cases of alignment and pattern exposure via the projection optical system, the two wafer stage positions can be measured accurately without any Abbe error, and the two wafer stages can be moved independently. It becomes possible to do.

Further, two wafer stages WS1, W
A length measurement axis B provided from both sides toward the projection center of the projection optical system PL along the direction in which S2 is arranged (here, the X-axis direction).
I1X, BI2X are always wafer stages WS1, WS
Irradiation is performed on the wafer stage 2 and the position of each wafer stage in the X-axis direction is measured.

In addition, the length measuring axis BI3Y perpendicularly intersects the length measuring axes BI1X and BI2X toward the detection center of the alignment system and the projection center position of the projection optical system PL (here, the Y axis direction). , BI4Y, and BI5Y are illuminated, and even when the wafer stage is moved and the length measurement axis is deviated from the reflecting surface, the position of the wafer stage can be accurately controlled by resetting the interferometer. Becomes possible.

Then, two wafer stages WS1, W
On S2, reference mark plates FM1 and FM2 are provided, respectively. The distance between the mark position on the reference mark plate and the mark position on the wafer by a correction coordinate system obtained by measuring the mark position on the wafer in advance using an alignment system is defined as By adding each to the reference plate measurement position before exposure, the wafer can be aligned without performing the baseline measurement for measuring the distance between the projection optical system and the alignment system as in the related art. It is not necessary to mount a large reference mark plate as described in JP-A-176468.

According to the above embodiment, since double exposure is performed using a plurality of reticles R, high resolution and DOF (depth of focus) can be obtained. However, in this double exposure method, since the exposure step has to be repeated at least twice, the exposure time is long and the throughput is greatly reduced. However, the throughput is greatly reduced by using the projection exposure apparatus of the present embodiment. High resolution and DO without lowering the throughput.
The effect of improving F is obtained. For example, in T1 (wafer replacement time), T2 (search alignment time), T3 (fine alignment time), and T4 (one exposure time), each processing time for an 8-inch wafer is set to T1: 9.
In the case of seconds, T2: 9 seconds, T3: 12 seconds, and T4: 28 seconds, the throughput THOR = 3600 if double exposure is performed by a conventional technique in which a series of exposure processing is performed using one wafer stage. / (T1 + T2 + T3 + T4 *
2) = 3600 / (30 + 28 * 2) = 41 [sheets / hour]
And the throughput (THOR = 3600 /) of the conventional apparatus for performing the single exposure method using one wafer stage.
(T1 + T2 + T3 + T4) = 3600/58 = 62
[Sheet / hour]), the throughput is reduced to 66%. However, using the projection exposure apparatus of this embodiment, T
When performing double exposure while processing 1, T2, T3, and T4 in parallel, the exposure time is longer, so that the throughput THOR = 3600 / (28 + 28) = 64 [sheets / hour].
Therefore, it is possible to improve the throughput while maintaining the high resolution and the DOF improvement effect. Also,
As the exposure time is longer, the number of EGA points can be increased, and the alignment accuracy is improved.

In the above embodiment, the case where the present invention is applied to an apparatus for exposing a wafer using a double exposure method has been described, but the present invention can also be applied to stitching which is a similar technique. Furthermore, as described above, the apparatus of the present invention performs two exposures with two reticles on one wafer stage side (double exposure, stitching), and on the other wafer stage side that can move independently. This is because, when the wafer exchange and the wafer alignment are performed in parallel, there is a particularly great effect that a higher throughput can be obtained than in the conventional single exposure, and the resolving power can be greatly improved. However, the scope of application of the present invention is not limited to this, and the present invention can be suitably applied even when exposure is performed by a single exposure method. For example, 8
Assuming that the respective processing times (T1 to T4) of the inch wafer are the same as described above, when the exposure processing is performed by the single exposure method using two wafer stages as in the present invention, T1, T2,
When T3 is set as one group (total 30 seconds) and parallel processing is performed with T4 (28 seconds), THOR = 3600
/ 30 = 120 [sheets / hour], which is the conventional throughput T for performing the single exposure method using one wafer stage.
It is possible to obtain almost twice as high throughput as HOR = 62 [sheets / hour].

In the above embodiment, the case where the scanning exposure is performed by the step-and-scan method has been described. However, the present invention is not limited to this, and the static exposure is performed by the step-and-repeat method. Of course, the present invention can be similarly applied to the EB exposure apparatus, the X-ray exposure apparatus, and even the stitching exposure for synthesizing the chips.

[0150]

As described above, claims 1 to 1
According to the invention described in Item 0, a projection exposure apparatus capable of further improving the throughput is provided.

Further, according to the inventions set forth in claims 11 and 12, it is possible to provide an unprecedented superior projection exposure method capable of further improving the throughput.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to an embodiment.

FIG. 2 is a perspective view showing a positional relationship among two wafer stages, a reticle stage, a projection optical system, and an alignment system.

FIG. 3 is a plan view showing a configuration of a drive mechanism of the wafer stage.

FIG. 4 is a diagram showing an AF / AL system provided in each of a projection optical system and an alignment system.

FIG. 5 is a diagram showing a schematic configuration of a projection exposure apparatus showing a configuration of an AF / AL system and a TTR alignment system.

FIG. 6 is a view showing the shape of the pattern forming plate of FIG. 5;

FIG. 7 is a plan view showing a state where a wafer exchange / alignment sequence and an exposure sequence are performed using two wafer stages.

8 is a diagram showing a state in which switching between a wafer exchange / alignment sequence and an exposure sequence in FIG. 7 has been performed.

FIG. 9 is a diagram showing a reticle stage for double exposure that holds two reticles.

10A is a diagram showing a state where the wafer is exposed using the reticle of pattern A in FIG. 9; and FIG. 10B is a diagram showing the state where the wafer is exposed using the reticle of pattern B in FIG. FIG.

FIG. 11 is a diagram showing an exposure order for each shot area on a wafer held on one of two wafer stages.

FIG. 12 is a diagram showing a mark detection order for each shot area on a wafer held on the other of the two wafer stages.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Projection exposure apparatus 24a, 24b Alignment system 38 Stage control means 90 Main controller 180 Center up 182 First loading guide 184 First unload arm 186 First slider 188 First load arm 190 Second slider 192 Second loading guide 194 Second unload arm 196 Third slider 198 Second load arm 200 Fourth slider W1, W2 Wafer WS1, WS2 Wafer stage PL Projection optical system BI1X to BI4Y Measurement axis RST Reticle stage R reticle

Claims (12)

[Claims] 1. A projection exposure apparatus for projecting and exposing an image of a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein the first exposure device holds the sensitive substrate and is movable in a two-dimensional plane. A substrate stage; a second substrate stage holding a sensitive substrate and movable in the same plane as the first substrate stage independently of the first substrate stage; and a substrate substrate provided separately from the projection optical system, At least one alignment system for detecting a mark on a stage or on a sensitive substrate held on the substrate stage; and a first axis passing through a projection center of the projection optical system and a detection center of the alignment system. A first length measurement axis for measuring the position of the first substrate stage in the first axis direction, and a position measurement of the second substrate stage in the first axis direction from the other side in the first axis direction. No. A length measurement axis, a third length measurement axis perpendicular to the first axis at the projection center of the projection optical system, and a fourth length axis perpendicular to the first axis at the detection center of the alignment system. And an interferometer system for respectively measuring the two-dimensional positions of the first substrate stage and the second substrate stage using these length measurement axes. 2. The projection exposure apparatus according to claim 1, wherein the alignment system is disposed on one side and the other side in the first axial direction with the projection optical system interposed therebetween. . 3. The method according to claim 1, wherein the first substrate stage and the second substrate stage perform an exposure operation by the projection optical system and a mark detection operation by the alignment system based on a measurement result of the interferometer system. First
The projection exposure apparatus according to claim 1, further comprising control means for controlling movement of the substrate stage and the second substrate stage. 4. The interferometer system according to claim 1, wherein the control unit controls the first substrate stage and the second substrate stage respectively when a mark is detected by the alignment system and when the projection optical system is exposed. 4. The projection exposure apparatus according to claim 3, wherein a length measurement axis and a fourth length measurement axis are switched. 5. A projection exposure apparatus for projecting and exposing an image of a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein the first exposure apparatus holds the sensitive substrate and is movable in a two-dimensional plane. A substrate stage; a second substrate stage holding a sensitive substrate and movable in the same plane as the first substrate stage independently of the first substrate stage; and a substrate substrate provided separately from the projection optical system, At least one alignment system for detecting a mark on a stage or a sensitive substrate held on the substrate stage; and one of the first substrate stage and the second substrate stage performs a mark detection operation by the alignment system. Control means for controlling the operation of both stages so that the other stage performs the exposure operation while performing the operation. 6. A transfer system for transferring a sensitive substrate between the first substrate stage and the second substrate stage, wherein the control means controls whether the one substrate stage is connected to the transfer system. 6. The operation of both stages is controlled so that the other substrate stage performs an exposure operation by the projection optical system while delivering a sensitive substrate and performing a mark detection operation by the alignment system.
3. The projection exposure apparatus according to claim 1. 7. The alignment system is disposed on each side of the projection optical system along a predetermined direction; and the control unit is provided on the first substrate stage or on a sensitive substrate held on the first substrate stage. Mark is detected by one of the alignment systems, and is detected on the second substrate stage or the second
The projection exposure apparatus according to claim 5, wherein a mark on the sensitive substrate held on the substrate stage is detected by another alignment system. 8. A projection exposure apparatus for projecting and exposing an image of a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein the first exposure device holds the sensitive substrate and is movable in a two-dimensional plane. A substrate stage; a second substrate stage that holds a sensitive substrate and is movable independently of the first substrate stage in the same plane as the first substrate stage; and a sensitive substrate that is sensitive to the first substrate stage and the second substrate stage. A transfer system for transferring the substrate; and a transfer system for transferring the sensitive substrate to the transfer system while one of the first substrate stage and the second substrate stage transfers the sensitive substrate. Control means for controlling the operation of the stage; 9. A mask stage on which a plurality of masks can be simultaneously mounted; and a drive system for driving a mask stage such that any one of the plurality of masks is selectively set to an exposure position. Claims 1 and 5,
Or the projection exposure apparatus according to 8. 10. The mask is mounted on a mask stage movable in a predetermined direction, and while the mask stage and one of the first substrate stage and the second substrate stage are synchronously moved,
The projection exposure apparatus according to claim 1, further comprising a stage control unit configured to project and expose the mask pattern on the sensitive substrate. 11. A projection exposure method for projecting and exposing an image of a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein said method is capable of independently moving within a two-dimensional plane while holding said sensitive substrate. Two substrate stages are prepared; one of the two substrate stages performs the operation of exchanging the sensitive substrate and the operation of detecting the mark on the substrate stage or the mark on the sensitive substrate held by the substrate stage. A projection exposure method, wherein an exposure operation for a sensitive substrate is performed on the other of the two substrate stages during at least one of the two stages. 12. The projection exposure method according to claim 11, wherein the operation of the two substrate stages is switched when the operation of each of the two substrate stages is completed.