JPH10199804A - Projection aligner, projection aligner method and manufacture of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection aligner device which can improve the controllability of a substrate stage. SOLUTION: The lengths of moving mirrors are decided, so that the relation Lm<Dw+2BL is established among the lengths Lm of the moving mirrors (24X, 24Y), a center distance BL between the projection center of a projection optical system PL and the detection center of a mark detection system AS, and the diameter Dw of a photosensitive substrate. Thus, a substrate stage 18 to which the moving mirrors are fitted can be made small and light, as compared with a conventional exposure device where the length of the moving mirrors is decided, so that the relation for the length Lm<Dw+2BL of the moving mirrors is established, and the position controllability of the substrate stage 18 can be improved.

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, a projection exposure method, and a device manufacturing method. More specifically, the present invention relates to a method for projecting a mask pattern used in manufacturing a semiconductor element, a liquid crystal display element and the like by a lithography process. The present invention relates to a projection exposure apparatus for exposing a sensitive substrate via an optical system, a projection exposure method, and a device manufacturing method using the same.

[0002]

2. Description of the Related Art For example, in a lithography process for manufacturing a micro device such as a semiconductor device, a liquid crystal display device, an imaging device (CCD) or a thin film magnetic head, a photomask or a reticle (hereinafter, referred to as a reticle) having a transfer pattern formed thereon.
A projection exposure apparatus that projects an image of a “reticle” onto a substrate (hereinafter, referred to as a “wafer”) such as a wafer or a glass plate coated with a photosensitive material (photoresist) via a projection optical system. Is used.

In this type of projection exposure apparatus, it is necessary to perform high-precision alignment (alignment) between a reticle and a wafer prior to exposure. In order to perform this alignment, a position detection mark (alignment mark) formed (exposed and transferred) in the previous photolithography process is provided on the wafer. By detecting the position of the alignment mark, the wafer is detected. (Or the circuit pattern on the wafer) can be accurately detected.

The alignment microscope for detecting the alignment mark is roughly classified into an on-axis system for detecting a mark via a projection lens and an off-axis system for detecting a mark without a projection lens. In a projection exposure apparatus using an excimer laser light source, which will become the mainstream in the future, an off-axis type alignment microscope is optimal. This is because the chromatic aberration of the projection lens is corrected for the exposure light,
In the case of on-axis, alignment light cannot be condensed or even if condensed, errors due to chromatic aberration are very large, whereas off-axis alignment microscopes are provided separately from the projection lens This is because free optical design is possible without considering such chromatic aberration, and various alignment systems can be used. For example, a phase contrast microscope, a differential interference microscope, or the like can be used.

FIG. 12 is a schematic plan view showing the vicinity of a wafer table of a projection exposure apparatus having a conventional off-axis type alignment microscope. As shown in FIG. 12, a wafer table as a substrate stage on which a wafer W is mounted has a Y moving mirror 80Y having a reflecting surface orthogonal to the Y axis and a reflecting surface orthogonal to the X axis direction. An X movable mirror 80X is provided. The Y movable mirror 8 is moved relative to the Y movable mirror 80Y by a Y-axis interferometer (not shown) (a measurement axis Y interferometer beam in the Y-axis direction passing through the projection center of the projection optical system PL and the detection center of the alignment microscope 82).
The displacement in the Y-axis direction from the reference position of 0Y is measured, whereby the Y coordinate of the wafer table is measured. On the other hand, the interferometer for measuring the X coordinate of the wafer table is an exposure X interferometer that projects an interferometer beam having a length measurement axis Xe in the X-axis direction passing through the projection center of the projection optical system onto the X movable mirror 80X. And an alignment X interferometer for projecting an interferometer beam on the length measurement axis Xa in the X-axis direction passing through the detection center of the alignment microscope 82.

As described above, at least three interferometers are provided for measuring the position of the wafer table because the alignment interferometers (length measuring axes Xa and Xa) are used at the time of alignment.
Y), the wafer table is positioned, and at the time of exposure, the exposure is positioned by an exposure interferometer (measuring axes Xe, Y), so that Abbe error due to rotation of the wafer table does not occur, and accurate alignment measurement is performed. And exposure can be performed.

[0007]

By the way, a Twyman-Green interferometer is generally used as an interferometer for controlling the position of a wafer table of a projection exposure apparatus. In this Twyman-Green interferometer, the fixed optical path (the optical path of the interferometer beam to a fixed mirror not shown) where the arm length (optical path length) does not change, and the arm length changes according to the position of the movable mirror. There is a moving optical path, and the arm lengths of these optical paths are compared to measure the position (relative displacement between the fixed mirror and the moving mirror).
If the interferometer beam is cut off (does not hit the movable mirror), position measurement becomes impossible, so it was necessary to prevent the interferometer beam from being cut off. For this reason, in the conventional projection exposure apparatus, in order to perform alignment measurement and exposure on the entire surface of the wafer W, a longer movable mirror (X in FIG. 12) on the wafer table is required. The length Lm of the moving mirror 80X) is such that the wafer diameter is Dw, Xe and Xa.
If BL is the distance between the two, it must be Dw + 2BL or more. That is, it is indispensable to set the length of the X movable mirror 80X so that the relationship of Lm> Dw + 2BL is established.

The size of wafers has increased with the times, and the diameter has recently reached 300 mm. For this reason, the length of the movable mirror is increased, and the wafer table to which the movable mirror is attached is inevitably increased in size.

Further, in the alignment system of the off-axis system, the alignment microscope is provided outside the projection optical system. A. As the size of the projection optical system increases, the distance between the projection optical system and the alignment microscope increases, and the length of the moving mirror increases and the size of the wafer table increases. It has become.

The enlargement of the wafer table (substrate stage) due to various factors as described above has now become a major problem. In other words, an increase in the size and weight of the substrate stage causes deterioration in controllability and a decrease in throughput.
This is because the size and weight of the entire apparatus are inevitably increased.

Under such circumstances, development of a technique for downsizing the substrate stage for enabling higher-speed substrate stage movement control and more precise positioning has been desired.

The present invention has been made under such circumstances, and a first object of the present invention is to provide a projection exposure apparatus that can particularly improve the control performance of a substrate stage.

It is a second object of the present invention to accurately manage the two-dimensional coordinate position of a substrate stage both when exposing a mask pattern via a projection optical system and when detecting a mark on a sensitive substrate by a mark detection system. It is an object of the present invention to provide a projection exposure apparatus capable of performing such operations.

A third object of the present invention is to provide a projection optical system having a high N.D. while holding the substrate stage at a fixed size.
A. It is an object of the present invention to provide a projection exposure apparatus capable of achieving a large field and a large field.

A fourth object of the present invention is to provide a moving mirror and a substrate stage which are reduced in size and weight without any inconvenience.
An object of the present invention is to provide a projection exposure apparatus capable of performing mark position measurement and pattern exposure through a projection optical system on the entire surface of a sensitive substrate.

It is a fifth object of the present invention to provide a projection exposure apparatus capable of ensuring the stability of a baseline.

A sixth object of the present invention is to provide a projection exposure apparatus capable of further reducing the size and weight of a movable mirror and a substrate stage on which the movable mirror is mounted.

A seventh object of the present invention is to perform mark position measurement and pattern exposure via a projection optical system on the entire surface of a sensitive substrate without any inconvenience even if the substrate stage is reduced in size and weight. And a projection exposure method.

Still another object of the present invention is to provide a device manufacturing method capable of manufacturing a highly integrated semiconductor device at low cost.

[0020]

According to a first aspect of the present invention, there is provided a projection exposure apparatus for exposing an image of a pattern formed on a mask (R) onto a sensitive substrate (W) via a projection optical system (PL). A substrate stage (18) on which the sensitive substrate (W) is mounted and moves in a two-dimensional plane; and a substrate stage (1) provided separately from the projection optical system (PL).
8) a mark detection system (AS) for detecting a mark on the sensitive substrate (W) or on the sensitive substrate (W);
An interferometer system (26) for managing dimensional coordinate positions; and a movable mirror (24) on the substrate stage (18) for measuring a displacement from a reference position by the interferometer system (26).
X, 24Y), and the movable mirror (24X, 24Y)
Lm, and a center-to-center distance BL between the projection center of the projection optical system (PL) and the detection center of the mark detection system (AS)
And the diameter Dw of the sensitive substrate, Lm <Dw +
The relationship of 2BL is established.

According to this, as shown in FIG. 3, the length Lm of the movable mirror (24X, 24Y) and the projection optical system (P
L) between the center distance BL between the projection center of the mark detection system (AS) and the detection center of the mark detection system (AS), and the diameter Dw of the sensitive substrate.
Since the relationship of Lm <Dw + 2BL is established, the substrate on which the movable mirror is mounted is compared with a conventional exposure apparatus in which the length of the movable mirror is determined so that the relationship of Lm> Dw + 2BL is established. The stage (18) can be reduced in size and weight.
8) Improvement of position control performance (specifically, positioning accuracy,
It is possible to improve the maximum speed and the maximum acceleration.

In this case, the interferometer system (2
6) may have any length measurement axis as long as it manages the two-dimensional coordinate position of the substrate stage (18). A first measurement axis (Y) in a first axis direction which is a direction connecting a projection center of the projection optical system (PL) and a detection center of the mark detection system (AS), and a first measurement axis (Y). ) At the projection center of the projection optical system (PL).
An axial second measuring axis (Xe) and the first measuring axis (Y)
May have at least a third measurement axis (Xa) in a second axis direction perpendicularly intersecting at the detection center of the mark detection system (AS). According to the interferometer system having such a length measuring axis, both when exposing the mask pattern via the projection optical system (PL) and when detecting the mark on the sensitive substrate (W) by the mark detection system (AS). The two-dimensional coordinate position of the substrate stage (18) can be accurately managed without causing a so-called Abbe error.

According to a third aspect of the present invention, in the projection exposure apparatus according to the second aspect, a predetermined reference point on the substrate stage (18) and the projection within the projection area of the projection optical system (PL). With the substrate stage (18) positioned at a position where the positional relationship with a predetermined reference point in the projection area of the optical system (PL) can be detected, the second measurement axis (Xe)
Resetting the interferometer (26Xe), and positioning the substrate stage (18) so that the reference point on the substrate stage (18) is located within the detection area of the mark detection system (AS). Interferometer with three measuring axes (Xa) (2
6Xa) is further provided with a control means (28) for resetting 6Xa).

According to this, in the control means (28), when the interferometer (26Xe) of the second measuring axis (Xe) becomes incapable of measuring, the interferometer (Xa) of the third measuring axis (Xa) becomes inoperative. 26X
While the a) is effective, the substrate stage (18) is temporarily moved based on the measured value so that the reference point on the substrate stage (18) is positioned on the first measurement axis. The movement of the substrate stage is resumed based on the measurement value of the interferometer (26Y) on the measurement axis (Y), and the projection optical system (PL)
Where the positional relationship between the predetermined reference point on the substrate stage (18) and the predetermined reference point in the projection area of the projection optical system can be detected in the projection area (the second measurement axis interferometer). With the substrate stage (18) positioned at the (reset position), the interferometer (26X
e) Reset. On the other hand, in the control means (28), when the interferometer (26Xa) of the third measurement axis (Xa) is in a measurement impossible state, the interferometer (2) of the second measurement axis (Xe)
6Xe) is valid, the substrate stage (18) is temporarily moved based on this measurement value so that the reference point on the substrate stage is positioned on the first measurement axis, and the first measurement axis is moved from this position. The movement of the substrate stage (18) is restarted based on the measurement value of the interferometer (26Y) in (Y) so that the reference point on the substrate stage is located within the detection area of the mark detection system (AS). The interferometer (26Xa) of the third measuring axis (Xa) is reset while the substrate stage (18) is positioned at a predetermined position (the reset position of the interferometer of the third measuring axis).

For this reason, even if both the interferometer on the second measuring axis and the interferometer on the third measuring axis become incapable of measurement during the movement of the substrate stage to the reset position of the interferometer, the first Since the substrate stage (18) can be positioned at the reset position based on the measured value of the length measurement axis (Y) by the interferometer, the size of the substrate stage (18) can be changed regardless of the size of the baseline amount BL. It can be set to about the diameter of the wafer (W). Therefore, while keeping the size of the substrate table constant, the projection optical system PL for improving the resolution is improved.
High N. A. And a large field can be easily achieved.

If the other interferometer can measure all the time while moving the substrate stage to the reset position of one of the interferometers of the second and third measuring axes, the other interferometer can be used. Based on the measured values of the interferometer and the interferometer on the first measurement axis,
Of course, the substrate stage may be directly positioned at the reset position of one interferometer.

In this case, the reference point in the projection area of the projection optical system (PL) is the projection center of the pattern image of the mask, and Projection center and substrate stage (18)
Position detecting means (52) for detecting the positional relationship with the upper reference point via the mask (R) and the projection optical system (PL).
A, 52B). In such a case, the position (the second measurement axis) at which the positional relationship between the predetermined reference point on the substrate stage (18) and the projection center of the mask pattern image can be detected in the projection area of the projection optical system (PL) When the substrate stage (18) is positioned at the reset position of the interferometer, the mask of the mask is reset by the position detecting means (52A, 52B) prior to the reset of the interferometer (26Xe) on the second measurement axis (Xe). The positional relationship between the projection center of the pattern image and the reference point on the substrate stage (18) can be detected via the mask (R) and the projection optical system (PL).

According to a fifth aspect of the present invention, in the projection exposure apparatus according to the second aspect, the first reference mark (30-1) and the second reference mark (32) are mounted on the substrate stage (18). -1, 32-2) and a first reference mark (30-1) of the reference plate (FP1) detected by the mark detection system (AS). The second reference marks (32-1, 32-2) of the reference plate (FP1) are located in the region at the same time as the projection optical system (PL).
The substrate stage (18) is positioned at a predetermined position (reset position of the second length measuring axis and the third length measuring axis of the interferometer) so as to be able to detect a positional relationship with a predetermined reference point in the projection area of FIG. And a control means (28) for resetting at least one of the interferometer on the second measurement axis and the interferometer on the third measurement axis in a state where the positioning is performed.

According to this, in the control means (28), the first reference mark (30-1) of the reference plate (FP1) is positioned within the detection area of the mark detection system (AS), and at the same time, the reference plate (FP1) The substrate stage (18) is moved to a predetermined position such that the second reference mark (32-1, 32-2) can be detected so as to detect the positional relationship with a predetermined reference point in the projection area of the projection optical system (PL). Position (the reset position of the interferometer of the second measuring axis and the third measuring axis), and in this state, at least one of the interferometer of the second measuring axis and the interferometer of the third measuring axis is set. Reset.

That is, when one of the interferometer on the second measuring axis and the interferometer on the third measuring axis cannot be measured by the control means, the other interferometer and the interferometer on the first measuring axis become inoperative. Based on the measured values, the substrate stage is positioned at the reset position, and the one interferometer (or both interferometers) is reset. Therefore, the interferometers on the second and third measurement axes are used. The moving range of the substrate stage is simply set in advance so that both are not in an unmeasurable state. Even if the movable mirror and the substrate stage are reduced in size and weight as described in claim 1, there is no inconvenience, and The entire surface can be subjected to mark position measurement and pattern exposure through a projection optical system.

In this case, the first reference mark (30-1) is previously placed on the reference plate (FP1) in the same positional relationship as the projection optical system (PL) and the mark detection system (AS).
And the second fiducial marks (32-1, 32-2).

In this case, the reference point in the projection area of the projection optical system (PL) is the projection center of the pattern image of the mask (R), and Center of projection of the pattern image and the reference plate (FP
Position detecting means (52A, 52B) for detecting the positional relationship with the second reference mark (32-1, 32-2) of 1) via the mask (R) and the projection optical system (PL). It is desirable to have. In such a case, when the substrate stage (18) is positioned at the above-described reset position, the second length measurement axis (X) is detected by the position detection means (52A, 52B).
Prior to resetting of the interferometer e) (or the interferometers of the second and third measurement axes), the projection center of the pattern image of the mask and the second reference mark (32-1) of the reference plate (FP1) are set. , 3
2-2) can be detected via the mask (R) and the projection optical system (PL).

[0033] In the projection exposure apparatus according to the sixth aspect, the control means (28) may be arranged such that the substrate stage (18) is positioned at the predetermined position as in the invention according to the seventh aspect. More preferably, the detection by the mark detection system (AS) and the detection by the position detection means are performed simultaneously. Here, “simultaneously” does not necessarily mean simultaneous with time, but means that the substrate stage is positioned at a predetermined position (reset position) and is stationary.

In this case, the so-called baseline measurement can be performed while the substrate stage is stationary, so that there is no influence of an interferometer measurement error due to air fluctuation or the like.
The stability of the baseline amount, which is the most important for the off-axis mark detection system, can be ensured.

The invention described in claim 8 is the invention according to claim 3 or 5.
3. The projection exposure apparatus according to claim 1, wherein the control unit resets the interferometer on the second measurement axis after the measurement of the mark on the sensitive substrate (W) by the mark detection system (AS). After the exposure on the sensitive substrate through the optical system is completed, the interferometer of the third measurement axis is reset.

According to this, when the interferometer of the third length measuring axis becomes unmeasurable during the exposure of the pattern on the sensitive substrate (W) via the projection optical system (PL), it is set to While the interferometer on the third measuring axis can be reset after the exposure, if the interferometer on the second measuring axis becomes incapable of measurement while the mark detection system finishes measuring the mark on the sensitive substrate. Can reset the interferometer on the second measurement axis after the measurement is completed. Therefore, there is no inconvenience in the measurement and exposure of the mark on the sensitive substrate, so that the interferometer on the third measurement axis cannot be measured during the exposure, or the second measurement cannot be performed during the measurement of the position detection mark. It is possible to allow the interferometer with the long axis to become unmeasurable, and accordingly, it is possible to shorten the length of the movable mirror, and more specifically, to reduce the length to about the diameter of the sensitive substrate (W). Become.

According to a ninth aspect of the present invention, there is provided a projection exposure method for exposing an image of a pattern formed on a mask (R) onto a sensitive substrate (W) via a projection optical system (PL). Detecting a positional relationship between a predetermined reference point on a substrate stage (18) on which the sensitive substrate (W) is mounted and an alignment mark on the sensitive substrate (W) mounted on the substrate stage (18); After that, a predetermined reference point on the substrate stage (18) is positioned in a projection area of the projection optical system (PL), and the substrate stage ( 18) detecting a positional shift of a predetermined reference point above and a coordinate position of the substrate stage; and detecting the positional relationship based on the detected positional relationship, the detected positional shift, and the detected coordinate position of the substrate stage. Substrate stage And movement control, and performing the alignment between the sensitive substrate mounted on the substrate stage and the pattern image of the mask.

According to this, after detecting the positional relationship between the predetermined reference point on the substrate stage (18) and the alignment mark on the sensitive substrate (W), the predetermined reference point on the substrate stage (18) is set. Positioning within the projection area of the projection optical system (PL), detection of a positional shift of a predetermined reference point on the substrate stage (18) with respect to a predetermined reference point in the projection area of the projection optical system, and detection of the positional shift In this case, the coordinate position of the substrate stage is detected, the movement of the substrate stage is controlled based on the results of the above-mentioned steps, and the pattern image of the mask is aligned with the sensitive substrate mounted on the substrate stage. Therefore, the substrate stage (18)
An interferometer (or coordinate system) that manages the position of the substrate stage when detecting the positional relationship between the predetermined reference point and the alignment mark on the sensitive substrate (W); Even if the interferometer (or coordinate system) that controls the position of the stage at the time of detection is the same or different, there is no inconvenience, and the alignment between the pattern image of the mask and the sensitive substrate mounted on the substrate stage can be improved. Can be performed with precision.

Therefore, for example, when an off-axis alignment system is used as a mark detection system for detecting an alignment mark, a predetermined reference point (the projection center of the pattern image of the mask) in the projection area of the projection optical system is detected. It is not necessary to measure the positional relationship with the center, that is, the baseline amount. As a result, there is no inconvenience even if the projection optical system and the alignment system are far apart, so the size of the substrate stage is independent of the baseline amount. It is possible to perform mark position measurement and pattern exposure via the projection optical system on the entire surface of the sensitive substrate without any disadvantage even if the substrate stage is reduced in size and weight. In this case, there is no influence of the fluctuation of the baseline amount.

According to a tenth aspect of the present invention, the projection of exposing an image of a pattern formed on a mask (R) to each of a plurality of shot areas on a sensitive substrate (W) via a projection optical system (PL). An exposure method, comprising the steps of: detecting position detection marks of some sample shot areas selected from a plurality of shot areas on the sensitive substrate;
Detecting a position with respect to a predetermined reference point on a substrate stage on which is mounted; based on the detection result, a positional relationship between all shot areas on the sensitive substrate and a predetermined reference point on the substrate stage. After the calculation, a predetermined reference point on the substrate stage is positioned within a projection area of the projection optical system, and the substrate is positioned with respect to the projection center of the pattern image of the mask by the projection optical system. Detecting a positional deviation from a predetermined reference point on the stage and a coordinate position of the substrate stage; and calculating the positional relationship based on the calculated positional relationship, the detected positional deviation, and the detected coordinate position of the substrate stage. Controlling the movement of the substrate stage, and aligning each of the shot areas on the sensitive substrate mounted on the substrate stage with the pattern image of the mask. To.

According to this, the positions of the predetermined reference point on the substrate stage (18) and the alignment mark for measuring the position of the sample shot area on the sensitive substrate (W) are respectively detected, and based on the detection results. After calculating the positional relationship between all shot areas on the sensitive substrate and a predetermined reference point on the substrate stage by calculation, the predetermined reference point on the substrate stage (18) is set to a projection optical system (PL). ) Is detected within the projection area, and the displacement of a predetermined reference point on the substrate stage (18) with respect to the projection center of the mask pattern image by the projection optical system is detected, and the coordinate position of the substrate stage at the time of detecting the displacement And the movement of the substrate stage is controlled based on the detection results of the above to
The pattern image of the mask is aligned with each of the shot areas on the sensitive substrate mounted on the substrate stage. In this case as well, the position of the substrate stage is detected when the positional relationship between the predetermined reference point on the substrate stage (18) and the alignment mark on the sensitive substrate (W) is detected. Even if the interferometer (or coordinate system) that manages and the interferometer (or coordinate system) that manages the position of the stage when detecting the positional deviation and detecting the coordinate position of the substrate stage are the same or different, The position of the mask pattern image and each of the predetermined shot areas on the sensitive substrate mounted on the substrate stage can be accurately adjusted without any inconvenience.

Therefore, as in the case of the ninth aspect, the size of the substrate stage can be set irrespective of the baseline amount, and even if the substrate stage is reduced in size and weight, there is no disadvantage. Mark position measurement and pattern exposure via the projection optical system can be performed on the entire surface of the sensitive substrate.

According to the eleventh aspect of the present invention, the mask (R)
A projection optical system (PL) for projecting an image of the pattern on a substrate (W); a substrate stage (18) mounted on the substrate and movable in a two-dimensional plane; the substrate stage or the substrate A mark detection system (AS) for detecting a mark formed on a substrate mounted on a stage; and measuring a position of the substrate stage with respect to a direction connecting a projection center of the projection optical system and a detection center of the mark detection system. A first measuring axis (Y), a second measuring axis (Xe) for measuring the position of the substrate stage in a direction perpendicular to the first measuring axis, and a second measuring axis. A third measurement axis (Xa) arranged at a predetermined distance in the direction of the first measurement axis to measure the position of the substrate stage in a direction perpendicular to the first measurement axis. An interferometer system (26) having: The pattern of the mask controls the movement of the substrate stage using the first length-measuring axis and the second length-measuring axis when transferred onto the substrate using an optical system,
A control system (28) for controlling the movement of the substrate stage using the first and third measurement axes when detecting the mark by the mark detection system.

According to this, the control system controls the movement of the substrate stage using the first measurement axis and the second measurement axis when transferring the mask pattern onto the substrate using the projection optical system. Since the movement of the substrate stage is controlled using the first and third measurement axes when a mark is detected by the mark detection system, for example, the projection optical system and the mark detection system are considerably separated. Even in this case, the two-dimensional coordinate position of the substrate stage can be managed without any trouble at the time of transferring the mask pattern via the projection optical system and at the time of detecting the mark on the substrate by the mark detection system.

In this case, the third measuring axis cannot be used when the first measuring axis and the second measuring axis are used, as in the twelfth aspect of the present invention. First
When using the length measuring axis and the third length measuring axis, the second
May be unusable. That is, when using the first measurement axis and the second measurement axis, the measurement beam of the third measurement axis deviates from the reflection surface (moving mirror) of the substrate stage,
The measurement beam of the second measurement axis may deviate from the reflection surface (moving mirror) of the substrate stage when using the first measurement axis and the third measurement axis. Therefore, the size of the substrate stage can be reduced.

In the projection exposure apparatus according to the twelfth aspect, as in the thirteenth aspect, after the detection of the mark by the mark detection system (AS) is completed, the control system (28) It is preferable that the interferometer on the second measurement axis be reset and the interferometer on the third measurement axis be reset after the transfer of the pattern using the projection optical system.

According to a fourteenth aspect of the present invention, the mask (R)
A projection optical system (PL) for projecting an image of the pattern on a substrate (W); a substrate stage (18) mounted on the substrate and movable in a two-dimensional plane; the substrate stage or the substrate A mark detection system (AS) for detecting a mark formed on a substrate mounted on a stage; and a projection center of the projection optical system and a detection center of the mark detection system for measuring a position of the substrate stage. , A second measurement axis (Xe) perpendicular to the first measurement axis at the optical axis center of the projection optical system, and a mark detection system (AS). An interferometer system (2) having a third measurement axis (Xa) perpendicularly intersecting the first measurement axis at the detection center;
6) and a control system (28) for resetting the interferometer on the third measurement axis when the mark is detected by the mark detection system.

According to this, when the pattern of the mask is transferred onto the substrate using the projection optical system, the position of the substrate stage is managed using the first and second length measurement axes of the interferometer system. By controlling the position of the substrate stage using the first and third measurement axes of the interferometer system when detecting the mark by the mark detection system, the mask pattern through the projection optical system is controlled. It is possible to accurately manage the two-dimensional coordinate position of the substrate stage without transferring so-called Abbe errors even when the mark is transferred onto the substrate by the mark detection system. In this case, the control system can reset the interferometer on the third length measurement axis when the mark is detected by the mark detection system, so that, for example, when the projection optical system and the mark detection system are far apart. However, after the transfer of the mask pattern, the substrate stage is moved to a position where the mark is detected by the mark detection system based on the measurement value of the interferometer on the first measurement axis, and the interference of the third measurement axis is performed at that position. By resetting the meter, accurate position management of the substrate stage at the time of mark detection becomes possible without any trouble.

According to a fifteenth aspect of the present invention, a mask (R)
A projection optical system (PL) for projecting an image of the pattern on a substrate (W); a substrate stage (18) mounted on the substrate and movable in a two-dimensional plane; the substrate stage or the substrate A mark detection system (AS) for detecting a mark formed on a substrate mounted on a stage; and a projection center of the projection optical system and a detection center of the mark detection system for measuring a position of the substrate stage. , A second measurement axis (Xe) perpendicular to the first measurement axis at the optical axis center of the projection optical system, and a detection center of the mark detection system. A third perpendicularly intersecting the first measurement axis
An interferometer system (26) having a measuring axis (Xa);
A control system (28) for resetting the interferometer on the second measurement axis when the mark is present in the projection area of the projection optical system.

According to this, when the pattern of the mask is transferred onto the substrate using the projection optical system, the position of the substrate stage is managed using the first and second length measurement axes of the interferometer system. By controlling the position of the substrate stage using the first and third measurement axes of the interferometer system when detecting the mark by the mark detection system, the mask pattern through the projection optical system is controlled. It is possible to accurately manage the two-dimensional coordinate position of the substrate stage without transferring so-called Abbe errors even when the mark is transferred onto the substrate by the mark detection system. In this case, the control system can reset the interferometer on the second measurement axis when the mark is in the projection area of the projection optical system. Even if the interferometer on the second measurement axis becomes unmeasurable during mark detection by the detection system, the interferometer on the second measurement axis can be reset before the exposure (transfer of the mask pattern) is performed. Will be possible. Therefore, accurate position management of the substrate stage at the time of exposure can be performed without any trouble.

In this case, when the detection system further includes a detection system (52A, 52B) for detecting the mark via the projection optical system (PL), the control is performed. The system (28) may reset the interferometer on the second measurement axis when the mark is detected by the detection system via the projection optical system.

According to a seventeenth aspect of the present invention, the mask (R)
Is transferred onto a substrate (W) via a projection optical system (PL), wherein a mark on a substrate stage (18) on which the substrate is mounted and moved is defined by the mask and the mask. By detecting with a detector for positioning the substrate, position information of the substrate stage with respect to the detector is obtained, and when the position information of the substrate stage with respect to the detector is obtained, the position of the substrate stage is obtained. The method is characterized in that an interferometer for measurement is reset.

According to this, the mark on the substrate stage is detected by the detector for aligning the mask and the substrate, so that when the position information of the substrate stage with respect to the detector is obtained, the position of the substrate stage is obtained. Resets the interferometer for measuring the position of the substrate stage, for example, even if the detector is provided at a position away from the projection optical system, while controlling the position of the substrate stage by the interferometer. Can be detected. Therefore, it is not necessary to manage the relative positional relationship between the pattern projection position and the detector.

In this case, the mark on the substrate stage may be, of course, a reference mark on a reference plate provided on the stage.
The mark on the substrate stage may include a mark on a substrate mounted on the substrate stage. Further, the detector is not limited to the detector provided at a position distant from the projection optical system as described above, and as in the invention according to claim 19, the detector is mounted on the substrate stage (18). The mark may be detected via the mask (R) and the projection optical system (PL).

According to a twentieth aspect of the present invention, a mask (R)
Is transferred onto a substrate (W) via a projection optical system (PL), and a mark on a substrate stage (18) on which the substrate is mounted and moved is transferred to the projection optical system. By detecting the position information of the substrate stage with respect to the projection optical system by detecting through the interferometer for measuring the position of the substrate stage when the position information of the substrate stage with respect to the projection optical system is determined It is characterized by resetting.

According to this, by detecting the mark on the substrate stage through the projection optical system, the interference for measuring the position of the substrate stage when the position information of the substrate stage with respect to the projection optical system is obtained. Since the scale is reset, the position of the substrate stage can be accurately managed by the interferometer when transferring the mask pattern using the projection optical system.

According to a twenty-first aspect of the present invention, a mask (R)
A projection exposure method for transferring the pattern onto a substrate (W), wherein the substrate is placed and moved by using a detector for aligning the mask and the substrate. The position information of the substrate stage is obtained, and when the position information of the substrate stage is obtained, an interferometer for measuring the position of the substrate stage is reset.

According to this, the interferometer for measuring the position of the substrate stage is reset when the position information of the substrate stage is obtained using the detector for aligning the mask and the substrate. Even when the detector is provided at a position distant from the projection optical system, for example, it is possible to detect the mark position by the detector while managing the position of the substrate stage by the interferometer. Therefore, it is not necessary to manage the relative positional relationship between the pattern projection position and the detector.

According to a twenty-second aspect of the present invention, a mask (R)
A projection exposure method for transferring the pattern on a substrate (W), wherein the substrate stage (1)
8) The position information of the substrate stage is obtained by detecting an upper mark, and when the position information of the substrate stage is obtained, an interferometer for measuring the position of the substrate stage is reset. And

According to this, when the position information of the substrate stage is obtained by detecting the mark on the substrate stage, the interferometer for measuring the position of the substrate stage is reset. The mark position can be detected while controlling the position of the stage.

According to a twenty-third aspect of the present invention, the mask (R)
A projection exposure method for transferring a pattern formed on a substrate (W) via a projection optical system (PL), comprising: a predetermined reference point on a substrate stage (18) for mounting the substrate; A first step of detecting a relative positional relationship with each of a plurality of shot areas on the substrate mounted on the substrate stage; after the first step, the projection optical system (P
L) detecting a reference point on the substrate via L); and, based on the detection results of the first step and the second step, transferring each shot area on the substrate to the projection optical system. And a third step of positioning.

According to this, the relative positional relationship between a predetermined reference point on the substrate stage and a plurality of shot areas on the substrate is detected, and thereafter, the reference point on the substrate is detected via the projection optical system. Each shot area on the substrate is aligned with the projection optical system based on these detection results. Also in this case, similarly to the invention according to the ninth aspect, coordinates for managing the position of the substrate stage when detecting the relative positional relationship between a predetermined reference point on the substrate stage and a plurality of shot areas on the substrate. The system and the coordinate system for managing the position of the stage when detecting the reference point on the substrate via the projection optical system are the same or different without any inconvenience.
Positioning of the pattern image of the mask with each of the predetermined shot areas on the substrate mounted on the substrate stage can be performed with high accuracy.

Therefore, as in the case of the ninth aspect, the size of the substrate stage can be set irrespective of the baseline amount, and there is no disadvantage even if the substrate stage is reduced in size and weight. Mark position measurement and pattern exposure via the projection optical system can be performed on the entire surface of the substrate.

In this case, the reference point on the substrate stage (18) may include a mark formed on a substrate mounted on the substrate stage.

According to a twenty-fifth aspect of the present invention, a semiconductor device is manufactured by using the projection exposure method according to the seventeenth or twenty-third aspect.

According to the projection exposure method of claim 17 or 23, the relative position relationship between the pattern projection position and the detector, that is, the size of the substrate stage regardless of the baseline amount. This makes it possible to perform mark position measurement and pattern exposure via the projection optical system on the entire surface of the substrate without any inconvenience even if the substrate stage is reduced in size and weight, and to improve the resolution. Of projection optics for A. And a large field can be easily achieved. Therefore, it becomes possible to manufacture a highly integrated semiconductor device, which was conventionally difficult to manufacture, at low cost.

[0067]

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 the configuration of a projection exposure apparatus 100 according to one embodiment. This projection exposure apparatus 100
Is a step-and-repeat type reduction projection exposure apparatus (so-called stepper).

The projection exposure apparatus 100 has an illumination system IOP
A reticle stage RST for holding a reticle R as a mask, a projection optical system PL for projecting an image of a pattern formed on the reticle R onto a wafer W as a substrate (or a sensitive substrate), and a wafer W for holding the wafer W. XY stage 20 that moves on a two-dimensional plane (within the XY plane), a driving system 22 that drives the XY stage 20, a CPU, a ROM,
A main controller 28 is provided as control means (and a control system) which is composed of a minicomputer (or microcomputer) including a RAM, an I / O interface, and the like, and controls the entire apparatus.

The illumination system IOP includes a light source (a mercury lamp or an excimer laser, etc.) and an illumination optical system including a fly-eye lens, a relay lens, a condenser lens, and the like. The illumination system IOP illuminates a pattern on the lower surface (pattern forming surface) of the reticle R with a uniform illuminance distribution by exposure illumination light IL from a light source. here,
As the illumination light for exposure IL, a bright line such as an i-line of a mercury lamp, or an excimer laser beam such as KrF or ArF is used.

A reticle R is fixed on the reticle stage RST via fixing means (not shown). The reticle stage RST is driven by a driving system (not shown) in the X-axis direction (perpendicular to the plane of FIG. 1) and in the Y direction. Axial direction (left-right direction in FIG. 1) and θ direction (rotation direction in XY plane)
Can be finely driven. Thus, reticle stage RST can position reticle R (reticle alignment) in a state where the center of the pattern of reticle R (reticle center) substantially matches optical axis Ae of projection optical system PL. FIG. 1 shows a state in which this reticle alignment has been performed.

The projection optical system PL has its optical axis Ae in the Z-axis direction orthogonal to the moving surface of the reticle stage RST.
Here, both sides are telecentric and a predetermined reduction magnification β
(Β is, for example, １ ／) is used.
For this reason, if the reticle R is illuminated with uniform illuminance by the illumination light IL in a state where the pattern of the reticle R and the shot area on the wafer W are aligned (aligned), the pattern on the pattern forming surface is changed. The image is reduced by the projection optical system PL at the reduction magnification β, projected onto the wafer W coated with the photoresist, and a reduced image of the pattern is formed in each shot area on the wafer W.

The XY stage 20 is actually a Y stage that moves on a base (not shown) in the Y axis direction.
An X stage is configured to move on the stage in the X axis direction. In FIG.
Shown as zero. A wafer table 18 as a substrate stage is mounted on the XY stage 20, and a wafer W is held on the wafer table 18 by vacuum suction or the like via a wafer holder (not shown).

The wafer table 18 can be minutely driven in the Z-axis direction integrally with the wafer holder holding the wafer W, and is also called a Z stage. The XY two-dimensional coordinate position of the wafer table 18 is managed by the interferometer system 26 via the movable mirror 24.

Here, on the wafer table 18, FIG.
As shown in FIG. 2, an X moving mirror 24X having a reflecting surface orthogonal to the X axis and a Y moving mirror 24Y having a reflecting surface orthogonal to the Y axis are provided.
The two laser interferometers 26Xe for measuring the position in the X-axis direction for measuring the relative displacement of each movable mirror from the reference position in the length-measuring axis direction by projecting a laser beam on the 4Y and receiving the reflected light. , 26Xa and a laser interferometer 26Y for position measurement in the Y-axis direction, which are representatively shown as a movable mirror 24 and an interferometer system 26 in FIG. That is, in the present embodiment, the laser interferometers 26Xe, 26Xa, and 26Y constitute the interferometer system 26.

Here, the length measuring axis Y of the laser interferometer 26Y and the length measuring axis Xe of the one X-axis laser interferometer 26Xe are
It intersects vertically at the optical axis Ae center (projection center) of the projection optical system PL, and the length measurement axis Y of the laser interferometer 26Y and the other X
The length measuring axis Xa of the axis laser interferometer 26Xa vertically intersects with the center of the optical axis Aa of the alignment sensor AS described later (coincident with the detection center). Thus, as described later, the Abbe error caused by yawing of the wafer table 18 does not affect the measurement of the position detection mark (alignment mark) on the wafer W and the exposure of the pattern on the wafer W. The position of the wafer table 18 can be accurately measured in each measurement axis direction.

In the present embodiment, as the three interferometers, a reference beam (not shown) is projected on a fixed mirror (not shown), and a measurement beam is projected on a movable mirror. 2. Description of the Related Art An interferometer that measures displacement of a movable mirror with respect to a fixed mirror based on an interference state in which reflected beams of beams are overlapped and interfered with each other is used. It is more desirable to use a two-frequency heterodyne interferometer as these interferometers in order to improve measurement accuracy.

Returning to FIG. 1, the measured value of the interferometer system 26 is supplied to the main controller 28, and the main controller 28 monitors the measured value of the interferometer system 26,
The wafer table 18 is positioned by driving the XY stage 20 via 2. In addition, the output of a focus sensor (not shown) is also supplied to the main controller 28, and the main controller 28 moves the wafer table 18 in the Z-axis direction (focus direction) via the drive system 22 based on the output of the focus sensor. Drive). That is, in this way, the wafer W becomes X,
Positioning is performed in three directions of Y and Z.

On the wafer table 18, a reference plate FP whose surface is the same as the surface of the wafer W is set.
Has been fixed. Various reference marks are formed on the surface of the reference plate FP (for this specific example,
See below).

Further, in this embodiment, an off-axis type alignment sensor AS as a mark detection system (and a detector) for detecting a position detection mark formed on the wafer W is provided on a side surface of the projection optical system PL. Have been. Here, steps are formed on the wafer W by exposure and processing up to the previous layer, and a position detecting mark (alignment mark) for measuring the position of each shot area on the wafer is included therein. This alignment mark is measured by the alignment sensor AS.

Here, as the alignment sensor AS, a so-called FIA (field image alignment) of an image processing method is used.
nment) -based alignment sensors are used. According to this, after the illumination light emitted from a light source (not shown) that emits broadband illumination light such as a halogen lamp passes through an objective lens (not shown), the wafer W (or the reference plate FP)
The reflected light from a wafer mark area (not shown) on the surface of the wafer W is sequentially transmitted through the objective lens and an index plate (not shown), and an image of the wafer mark is formed on an imaging surface such as a CCD (not shown), and An image of the index on the index plate is formed. The photoelectric conversion signals of these images are processed by a signal processing circuit (not shown) in the signal processing unit 16, and a calculation circuit (not shown) calculates a relative position between the wafer mark and the index. Conveyed to. Main controller 28
Then, the position of the alignment mark on the wafer W is calculated based on the relative position and the measurement value of the interferometer system 26.

Note that an FIA is used as the alignment sensor.
LIA (Laser Interferometric Alignmen)
t) Other optical alignment systems such as LSA (Laser Step Alignment) system and LSA (Laser Step Alignment) system, other optical devices such as phase contrast microscope and differential interference microscope, and atomic level unevenness on the sample surface using the tunnel effect. STM (Scanning Tunne)
l Non-optical devices such as a microscope (scanning tunnel microscope) and AFM (atomic force microscope) that detects atomic and molecular level irregularities on the sample surface using atomic force (attractive and repulsive forces). It is also possible to use.

Further, in the projection exposure apparatus of this embodiment, the reference plate FP is provided above the reticle R via the projection optical system PL.
Reticle alignment microscopes 52A and 52B are provided as position detecting means (and a detector) for simultaneously observing the image of the upper reference mark and the mark on the reticle R. The detection signals S1 and S2 of the reticle alignment microscopes 52A and 52B are supplied to the main controller 28. In this case, the deflection mirrors 54A and 54B for guiding the detection light from the reticle R to the reticle alignment microscopes 52A and 52B, respectively, are unitized with the respective reticle alignment microscopes 52A and 52B, and a pair of microscope units 56A, 56B are configured. These microscope units 56A, 56B
When the exposure sequence is started, a mirror driving device (not shown) retracts to a position not covering the reticle pattern surface in response to a command from the main control device 28.

In this embodiment, as shown in FIG. 3, movable mirrors 24X and 24Y having a length Lm slightly longer than the diameter Dw of the wafer W are used.

For this reason, in the state shown in FIG. 4A where the measured value of the interferometer 26Y is maximum (the measurement beam of the measurement axis Y is maximum) within the movement range of the wafer table 18, the measurement of the measurement axis Xe is not possible. In the state of FIG. 4B in which the measurement beam is prevented from hitting the movable mirror 24X and the measurement value of the interferometer 26Y is minimum (the measurement beam of the measurement axis Y is minimum), the measurement axis Xa The measurement beam does not hit the movable mirror 24X. Here, the state in FIG. 4A is when the upper contour line of the wafer W in FIG. 4A is at the detection center of the alignment sensor AS, and the state in FIG. 4B when the lower contour line of the wafer W in FIG. 4B overlaps the projection center of the projection optical system PL.

In these cases, if the position of the wafer table 18 is controlled by an interferometer similar to the conventional one,
The former makes it difficult to control the position of the wafer table 18 during exposure, while the latter makes it difficult to control the position of the wafer table 18 during alignment.
Position control becomes difficult. In order to avoid such inconvenience, in the present embodiment, main controller 28 has a function of resetting the interferometer. This reset function will be described later in detail.

On the other hand, for the position control of the wafer table in the Y direction, a measuring beam of the measuring axis Y is used, and the movable mirror 24Y
Is longer than the diameter of the wafer W, the position of the wafer table 18 can be managed (or monitored) in the entire range of the exposure range by the projection optical system PL and the alignment measurement range by the alignment sensor AS. No problem.

<< First Reset Function of Interferometer >> Next, the control operation of main controller 28 in the present embodiment will be described focusing on the first reset function of the interferometer.

The first reset function of main controller 28 is such that when wafer table 18 moves within the XY plane, one of the measurement beams of measurement axes Xe and Xa is cut off, and interference having the measurement axis is performed. When the measurement becomes impossible, the wafer table 18 is measured based on the interferometer 26Y of the measuring axis Y (the measuring beam of the interferometer does not break) and the interferometer of the other measuring axis. To the predetermined reset position,
This is a function of resetting the interferometer on the one measurement axis at the reset position.

As described above, the upper surface of the wafer table 18 is provided with a reference plate FP whose surface is set to be substantially the same height as the surface of the wafer W. As disclosed in Japanese Unexamined Patent Publication No. 4-324923, here, a reference plate FP1 called a large FM as shown in FIGS. 5A and 5B is used. On the reference plate FP1, FIG.
As shown in the figure, a predetermined interval in the longitudinal direction is set at the center in the short direction (this interval matches the design value of the center distance BL between the projection center of the projection optical system PL and the detection center of the alignment sensor AS). The marks 30-1 and 30-2 for the alignment sensor are formed as the first fiducial marks, and the marks 32-1 and 32 for the reticle microscope as the pair of second fiducial marks are formed on both sides of the mark 30-2. -2 is formed symmetrically. That is, the reference marks 30-1, 30-2 and the reference marks 32-1, 32-2 on the reference plate FP1.
Are formed in a predetermined positional relationship with each other.

Assuming that the wafer table 18 is at the position shown in FIG. 5A, for example, in a state where the wafer exchange has been completed, in this state, the measurement beam of the measurement axis Xe is cut off. Since the measurement beam on the measurement axis Y is not broken and the measurement beam on the measurement axis Xa is not broken, the measured values of the interferometers 26Y and 26Xa are not
8 has been entered. Therefore, main controller 28 can recognize the XY two-dimensional coordinate position of wafer table 18 at this time based on the measured values of interferometers 26Y and 26Xa, and measures the length of length measuring axis Xe based on the Y coordinate. He accurately recognizes that the beam is cut off. However, at this time, the interferometer 26Xa has been reset as described later, and the wafer table 18
(a, Y) coordinate system.

In this state, alignment measurement (hereinafter referred to as “EGA” measurement as appropriate) is performed. That is, the main controller 28 monitors the position of the position detection mark (alignment mark) of a predetermined specific sample shot among the plurality of shot areas on the wafer W, and monitors the measurement values of the interferometers 26Y and 26Xa. Then, the wafer table 18 is sequentially moved integrally with the XY stage 20 via the drive system 22, and is performed on the (Xa, Y) coordinate system based on the output of the alignment sensor AS. Then, by using the measured wafer mark position of each sample shot and the array data of the shot area in design, for example,
By performing a statistical operation by the least square method as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-44429, the entire array data of the plurality of shot areas on the wafer is obtained. However, the position of the first fiducial mark 30-1 is determined by the interferometer 2 prior to the alignment measurement.
By detecting the reference mark 30-1 by the alignment sensor AS when resetting 6Xa, (Xa, Y)
Is measured on the coordinate system of the reference plate FP.
1 is converted to data based on the first reference mark 30-1.

After the completion of the above alignment measurement (in this state, the interferometer beam of the interferometer 26Xe is assumed to be cut off), the process proceeds to the exposure processing sequence.

That is, main controller 28 controls interferometer 2
While monitoring the measured values of 6Y and 26Xa, the wafer table 18 is positioned at a position (reset position) where the reference mark 30-1 on the reference plate FP1 which is known in advance is located within the detection area of the alignment sensor AS. In a state where the wafer table 18 is positioned at the reset position, as shown in FIG. 5B, the measurement beam of the measurement axis Xe hits the X movable mirror 24X, and the reference plate F
The second reference marks 32-1 and 32-2 and the first reference mark 30-2 on P1 are located in the projection area of the projection optical system PL. This is because, as described above, the distance BL between the measurement axes Xe and Xa and the distance between the first fiducial marks 30-1 and 30-2 are determined to be equal on the design value.

In this state, main controller 28 uses reticle alignment microscopes 52A and 52B to control reference plate F
The images of the marks 32-1 and 32-2 on P1 via the projection optical system PL and the reticle marks on the reticle R respectively corresponding to the marks are simultaneously observed, and the detection signals of the reticle alignment microscopes 52A and 52B are detected. , The positional deviation between the marks 32-1 and 32-2 and the reticle mark corresponding to each mark is detected. This detection, that is, the positional relationship between the second reference marks 32-1 and 32-2 of the reference plate FP1 and the projection center of the projection optical system PL (which substantially matches the projection center of the pattern image of the reticle R). The moment the detection is completed, the interferometer 26Xe of the length measuring axis Xe is reset. As described above, the interferometer 26Xe is reset when the position of the wafer table 18 is detected using the alignment microscopes 52A and 52B and the second reference marks 32-1 and 32-2 of the reference plate FP1. That is, the projection optical system PL
The interferometer 26Xe is reset when the position of the wafer table 18 with respect to the projection center is detected. here,
The resetting is usually performed by setting the count value of a counter that counts the measurement value of the interferometer 26Xe to zero. However, the reset value is not limited to zero, and another easy-to-use value may be input.

As a result, the position of the wafer table 20 is managed on the coordinate system (Xe, Y).

In the main controller 28, the reference plate FP by the reticle alignment microscopes 52A and 52B is used.
In parallel with the detection of the positional relationship between the first second reference marks 32-1 and 32-2 and the projection center of the projection optical system PL, the position of the first reference mark 30-1 is detected by the alignment sensor AS, that is, the alignment sensor AS detection center (index center)
The relative positional relationship between the first reference mark 30-1 and the first reference mark 30-1 is also detected. Thereby, the distance between the center of projection of the reticle pattern image by the projection optical system PL (the projection center of the projection optical system PL) and the center of detection of the alignment sensor AS, that is, the baseline amount can be accurately and immediately measured. As a result, the most important baseline can be stabilized by the off-axis alignment method. Further, since the baseline measurement is performed while the wafer table 18 is at rest, the influence of air fluctuation of the interferometer can be eliminated. Further, based on the result of simultaneous detection of the reference mark on the reference plate FP1 by the reticle alignment microscopes 52A and 52B and the alignment sensor AS,
The rotation of the reticle R is also known.

Here, the first fiducial mark 30-2 on the fiducial plate FP1 is attributable to the mounting error of the fiducial plate FP-1 on the wafer table 18 and the manufacturing error, so that the fiducial plate F
It is provided for correcting an error when P-1 is rotating. That is, after the baseline measurement as described above, the main controller 28 moves the wafer table 18 in the + Y direction to position the mark 30-2 in the detection area of the alignment sensor AS, and detects the detection signal of the alignment sensor AS. Is used to measure the position of the mark 30-2. When measuring this mark, the measurement axis Xe
Must not come off the mirror. When the wafer table 18 is moved for this measurement, Xa or Xe
Is not changed, the alignment sensor A
If the X coordinates of 30-1 and 30-2 detected in S are different, a rotation error of the reference plate FP is obtained based on the difference between the two.
The measurement value such as the baseline is corrected by this error.

The reticle rotation may be corrected by the reticle rotation amount obtained as a result of the simultaneous detection of the reference marks on the reference plate FP1. So-called multi-point EGA measurement within a shot (for example, Japanese Patent Application Laid-Open No. 6-27549).
6), the rotation, magnification, and orthogonality error of each shot are known, and the reticle R is rotated integrally with the reticle stage RST in accordance with the result, and correction or projection optics is performed. The magnification of the system PL may be adjusted by a magnification correction mechanism (not shown). As a magnification correction mechanism in such a case, for example, a mechanism for driving a specific lens element constituting the projection optical system PL in the vertical direction or a mechanism for adjusting the internal pressure of a sealed chamber formed between the specific lens elements is used. You can do it.

Then, main controller 28 measures the positional deviation error and the first reference mark 30-1 calculated earlier.
Array data and the baseline amount (first reference mark 30-1 and second reference marks 32-1 and 32-1, 32
-2 relative positional relationship) and the interferometer 26
The reticle pattern is sequentially exposed on the wafer in a step-and-repeat manner while controlling the opening and closing of the shutter in the illumination optical system while positioning each shot area on the wafer W at the exposure position while monitoring the measurement values of Y and 26Xe. I do.

When exposure of the reticle pattern to all shot areas on wafer W is completed in this manner,
The wafer table 18 is returned to the wafer replacement position shown in FIG. 5A. Prior to this, the interferometer 26Xa is reset as follows.

In this case, during the exposure on the wafer W, the measurement beam on the measurement axis Xa may be deviated from the movable mirror 24X. However, the wafer table 18 during the exposure uses the coordinate system (Xe, Y ), The main controller 28 sets the second reference marks 32-1 and 32-2 on the reference plate FP1 which are known in advance in the projection area of the projection optical system PL in the projection center (this is The wafer table 18 is moved to a predetermined reset position while monitoring the measured values of the interferometers 26Y and 26Xe so as to be located at a position where a positional relationship with the projection center of the pattern image of the reticle R can be detected. Position. The wafer table 18 is located at the reset position.
In the state where is positioned, as shown in FIG. 5 (B), the measurement beam of the measurement axis Xa has hit the X movable mirror 24X, and the first reference mark 30-1 on the reference plate FP1.
Is located in the detection area of the alignment sensor AS. This is because, as described above, the distance BL between the measurement axes Xe and Xa and the distance between the first fiducial marks 30-1 and 30-2 are determined to be equal on the design value.

In this state, the main controller 28 uses the alignment sensor AS to operate the mark 30-1 on the reference plate FP1.
And the interferometer 26Xa is reset at the same time. As described above, the wafer table 1 is used by using the alignment sensor AS and the reference mark 30-1 of the reference plate FP1.
When the position 8 is detected, the interferometer 26Xa is reset. That is, when the position of wafer table 18 with respect to the detection center of alignment sensor AS is detected, interferometer 26Xa is reset. Also, the reference plate FP1
Of the reference mark 30-1 is measured on the coordinate system (Xa, Y).

As a result, the wafer table 18 becomes (X
a, Y) It is managed by a coordinate system. Then, wafer exchange and alignment measurement are performed on the coordinate system (Xa, Y) of the interferometer 26Xa.

<< Second Reset Function of Interferometer >> Next, the control operation of main controller 28 in the present embodiment will be described focusing on the second reset function of the interferometer.

The second reset function of main controller 28 is such that when wafer table 18 is moved in the XY plane, one or both of the length measuring beams Xe and Xa are cut off, When the interferometer having the above-mentioned condition becomes impossible to measure, the predetermined reference point of the wafer table 18 is set based on the measurement value of the interferometer 26Y of the measuring axis Y (the measuring beam of the interferometer does not break). This is a function of positioning the wafer table 18 so as to be located at each reset position, and resetting the interferometer of the corresponding measurement axis at the reset position.

As described above, the upper surface of the wafer table 18 is provided with the reference plate FP whose surface is set to be substantially the same height as the surface of the wafer W. It is assumed that a reference plate FP2 called a small FM as shown in FIGS. 7A and 7B is used. As shown in FIG. 6B, a reference mark 30-3 for an alignment sensor is formed at the center of the reference plate FP2, and a pair of reticle microscopes is provided on both sides in the longitudinal direction of the mark 30-3. Reference marks 32-3, 32-4
Are formed symmetrically. Reference plate FP2
The reference mark 30-3 and the reference marks 32-3, 32-4 are formed in a predetermined positional relationship with each other.

When the wafer replacement is completed, the measurement beam on the measurement axis Xe is cut off, but the measurement beam on the measurement axis Y is not cut off, and the measurement beam on the measurement axis Xa is cut off. Are not cut off, and the measurement values of the interferometers 26Y and 26Xa are input to the main controller 28. Therefore, main controller 28 can recognize the XY two-dimensional coordinate position of wafer table 18 at this time based on the measured values of interferometers 26Y and 26Xa, and measures the length of length measuring axis Xe based on the Y coordinate. He accurately recognizes that the beam is cut off. However, at this time, the interferometer 26
Xa is reset as described later, and the wafer table 18 is managed in the (Xa, Y) coordinate system.

In this state, alignment measurement is performed. That is, the main controller 28 monitors the position of the position detection mark (alignment mark) of a predetermined specific sample shot among the plurality of shot areas on the wafer W, and monitors the measurement values of the interferometers 26Y and 26Xa. The wafer table 18 is sequentially moved integrally with the XY stage 20 via the drive system 22 while
This is performed on the (Xa, Y) coordinate system based on the output of S. Then, using the measured wafer mark position of each sample shot and the array data of the shot area in design,
For example, a statistical operation by the least squares method as disclosed in Japanese Patent Application Laid-Open No. 61-44429 or the like is performed to obtain the entire array data of the plurality of shot areas on the wafer. However,
It is desirable that the calculation result be converted into data based on the reference mark 30-3 on the reference plate FP2. Thereby, the reference mark 30-3 as shown by each arrow in FIG.
Is obtained as a reference. The position of the reference mark 30-3 is determined on the (Xa, Y) coordinate system by detecting the reference mark 30-3 with the alignment sensor AS when the interferometer 26Xa is reset, which is performed prior to the alignment measurement. It has been measured (this will be described in detail later).

After the above alignment measurement is completed (in this state, the interferometer beam of the interferometer 26Xe is cut off), the process proceeds to the exposure processing sequence.

That is, main controller 28 controls interferometer 26
While monitoring the measured value of Xa, the wafer table 18 is moved in the −X direction or + X direction in FIG. 2 until the Xa coordinate becomes 0.
It is driven in a direction (this direction is determined according to the setting of the end position of the alignment measurement). Thereby, the reference plate FP
The reference mark 30-3 at the center of No. 2 substantially coincides with the measurement axis Y. Then, main controller 28 monitors wafer table 1 while monitoring the measurement value of interferometer 26Y according to the Y coordinate value (for example, zero) of projection optical system PL known in advance.
8 in the + Y direction to move the reference plate FP2 to the projection optical system PL.
(A position at which the relative position between the reference marks 32-3 and 32-4 on the reference plate and the projection center of the projection optical system PL can be detected) is set at a predetermined position (interferometer). 26Xe reset position).
The state at this time is shown in FIG.

In this state, main controller 28 uses reticle alignment microscopes 52A and 52B to control reference plate F
The images of the marks 32-3 and 32-4 on P2 via the projection optical system PL and the reticle marks on the reticle R corresponding to the marks are observed simultaneously, and the detection signals of the reticle alignment microscopes 52A and 52B are detected. , The positional deviation between the marks 32-3 and 32-4 and the reticle mark corresponding to each mark is detected. This detection, that is, the detection of the positional relationship between the reference marks 32-3 and 32-4 of the reference plate FP2 and the projection center of the projection optical system PL (which substantially coincides with the projection center of the pattern image of the reticle R) is performed. At the moment of the completion, the interferometer 26Xe of the measuring axis Xe is reset.
As described above, when the position of the wafer table 18 is detected using the alignment microscopes 52A and 52B and the second reference marks 32-3 and 32-4 of the reference plate FP2, the interferometer 26 is used.
Xe is reset. That is, the interferometer 26Xe is reset while the position of the wafer table 18 with respect to the projection center of the projection optical system PL is detected. Here, the reset is usually performed by setting the count value of a counter that counts the measurement value of the interferometer 26Xe to zero, but the value is not limited to zero and may be another easy-to-use value.

As a result, the position of the wafer table 20 is managed on the coordinate system (Xe, Y).

Here, in the case of FIG. 7B, the interferometer 2
Since the interferometer beam of the interferometer 26Xa cannot be cut at the reset position of 6Xe, the movement of the wafer table 18 from the alignment measurement end position to the reset position of the interferometer 26Xe is based on the measurement values of the interferometers 26Xa and 26Y. It may be performed along a straight path.

However, for example, if the distance between the length measurement axes Xe and Xa is farther away, the wafer table 1
During the movement of 8, the interferometer beam on the measurement axis Xa is cut off (the interferometer beam on the measurement axis Xe is also cut off at this time), and the position control of the wafer table 18 becomes impossible. On the other hand, as described above, the wafer table 18
Is temporarily moved in the -X direction or + X direction, and then moved in the + Y direction, the interferometer 26Xe is moved to the predetermined reset position (when the reference plate (A position immediately below the optical system PL).

Therefore, according to the reset function of the second interferometer, no matter how long the distance between the measurement axes Xe and Xa (that is, the base line amount BL) is long, the movable mirror 24 is required.
The length of X can be made substantially equal to the diameter of the wafer W.

The wafer table 18 when the length measuring beams of the length measuring axes Xa and Xe are both cut off.
During the movement of the XY stage 20 in the Y-axis direction,
It is desirable that the position of the stage does not change. Therefore, while the use of the X interferometer is disabled, the servo control of the position in the X-axis direction is performed based on another sensor, or the X stage itself is controlled. Just lock it.

In the main controller 28, the measurement result of the above-mentioned displacement error, the shot arrangement data based on the previously calculated reference mark 30-3, the reference mark 30-3 and the reference marks 32-3, 32-3 4 and based on the positional relationship
While monitoring the measurement values of the interferometers 26Y and 26Xe, while positioning each shot area on the wafer W at the exposure position, while controlling the opening and closing of the shutter in the illumination optical system, a reticle pattern is formed on the wafer by a step-and-repeat method. Expose sequentially.

When exposure of the reticle pattern to all shot areas on wafer W is completed in this manner,
The wafer table 18 is returned to the wafer exchange position. Prior to this, the interferometer 26Xa is reset as follows.

In this case, during the exposure on the wafer W, the measurement beam of the measurement axis Xa may be deviated from the movable mirror 24X. However, the wafer table 18 during the exposure uses the coordinate system (Xe, Y ), The main controller 28 moves the wafer table 18 after the exposure, while monitoring the measurement value of the interferometer 26Xe to a position where the Xe coordinate becomes zero. That is, the wafer table 18 is moved in the X direction until the measured value of the interferometer 26Xe becomes the Xe coordinate value when the interferometer 26Xe is reset. Thus, the reference mark 30-3 of the reference plate FP2 substantially coincides with the measurement axis Y. Next, the main controller 28
Then, the wafer table 18 is moved in the −Y direction while monitoring the measurement value of the interferometer 26Y according to the Y coordinate value of the detection center of the alignment sensor AS which is known in advance, and the reference plate F
The wafer table 18 is positioned at a predetermined position (the reset position of the interferometer 26Xa) where the reference mark 32-3 of P2 is located within the detection area of the alignment sensor AS. This state is shown in FIG.

In the state where the wafer table 18 is positioned at the reset position, as shown in FIG. 7A, the length measuring beam of the length measuring axis Xa impinges on the X movable mirror 24X, and the reference beam FP2 First fiducial mark 30-3
Is located in the detection area of the alignment sensor AS.

In this state, main controller 28 uses alignment sensor AS to mark 30-3 on reference plate FP2.
And the interferometer 26Xa is reset at the same time. As described above, the wafer table 1 is used by using the alignment sensor AS and the reference mark 30-3 of the reference plate FP2.
When the position 8 is detected, the interferometer 26Xa is reset. That is, when the position of wafer table 18 with respect to the detection center of alignment sensor AS is detected, interferometer 26Xa is reset. Also, the reference plate FP2
Is measured on the coordinate system (Xa, Y).

As a result, the wafer table 18 becomes (X
a, Y) It is managed by a coordinate system. Then, wafer exchange and alignment measurement are performed on the coordinate system (Xa, Y) of the interferometer 26Xa.

As described above, according to the projection exposure apparatus of the present embodiment, as shown in FIG.
Since a length Lm smaller than (Dw + 2BL) and slightly longer than the wafer diameter Dw is used as X and 24Y, a conventional exposure apparatus using a moving mirror longer than (Dw + 2BL) is used. In comparison, the size and weight of the wafer table 18 on which the movable mirror is mounted and the XY stage 20 on which the movable mirror is mounted can be reduced, thereby improving the position control performance of the wafer table 18 (and the XY stage 20). it can. Also, as a matter of course, the size of the entire apparatus can be reduced.

In order to perform the alignment measurement by the alignment sensor AS and the exposure by the projection optical system PL, it is theoretically sufficient if the length Lm of the movable mirror is the same as the wafer diameter Dw. However, it is necessary to make the length of the movable mirror slightly larger than the wafer diameter Dw because it is necessary to consider a margin for improving the flatness of both ends of the movable mirror reflection surface and the beam diameter.

Further, according to the above embodiment, since the main controller 28 has the first and second reset functions of the interferometer for resetting the interferometer at the timing between the alignment and the exposure, the wafer is provided with the first and second reset functions. Even though the table 18 has a substantially square shape slightly larger than the diameter of the wafer, any operation of alignment mark measurement and exposure can be performed without any trouble.

In particular, main controller 18 using reference plate FP1 called large FM as the reference plate described above.
According to the interferometer reset operation, the baseline immediately after the alignment measurement can be measured, so that the stability of the most important baseline amount can be ensured by the off-axis alignment sensor. Since the measurement can be performed in the stationary state, the measurement error of the interferometer due to air fluctuation or the like is irrelevant.

On the other hand, according to the interferometer reset operation of the main controller 18 using a reference plate FP2 called a small FM as a reference plate, the size of the wafer table 18 is changed to the wafer W diameter regardless of the size of the baseline amount BL. It is possible to set to about.

Therefore, while maintaining the size of the wafer table 18 constant, the high N.P. of the projection optical system PL for improving the resolving power is improved. A. And a large field can be easily achieved.

Note that, instead of the Y-axis interferometer 26Y in FIG.
A yawing interferometer having measurement axes Y1 and Y2 as shown in FIG. 9 may be provided. According to this yawing interferometer, the yaw amount of the wafer table 18 can be easily obtained by dividing the difference between the measured values of the Y1 axis and the Y2 axis by the inter-axis distance Yy, and the measurement of the Y1 axis and the Y2 axis can be performed. By averaging the values, it is possible to perform the Y coordinate measurement of the wafer table 18 equivalent to the interferometer of the measurement axis Ya corresponding to the Y axis interferometer 26Y of FIG. Similarly, it is conceivable to attach a yawing interferometer also on the X side, but on the X side, both length measuring axes Xa and Xe must be set to two, which is complicated. Therefore, in the case of FIG. 9, a yaw interferometer is provided only on the Y-axis side assuming that the orthogonality of the movable mirrors 24X and 24Y does not change. However, the moving mirrors 24X and 24Y
When the orthogonality changes, the yaw interferometer is used for both X and Y, or the relationship when the measuring beams of the three measuring axes Xa, Xe, and Y are not cut off is stored and the change is stored. You may measure it.

<< Device Manufacturing Method >> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus and exposure method in a lithography step will be described.

FIG. 10 shows devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads,
The flowchart of the example of manufacture of a micromachine etc. is shown. As shown in FIG.
In 1 (design step), a function / performance design of a device (for example, a circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step)
A mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step)
A wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), actual circuits and the like are formed on the wafer by lithography using the mask and the wafer prepared in steps 201 to 203, as described later. Next, step 205 (device assembling step)
, Device assembly is performed using the wafer processed in step 204. Step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.

Finally, step 206 (inspection step)
, Inspections such as an operation confirmation test and a durability test of the device manufactured in step Y5 are performed. After these steps, the device is completed and shipped.

FIG. 11 shows a detailed flow example of step 204 in the case of a semiconductor device. In FIG. 11, step 211 (oxidation step)
In, the surface of the wafer is oxidized. Step 212
In the (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), electrodes are formed on the wafer by vapor deposition. Step 2
At 14 (ion implantation step), ions are implanted into the wafer. Steps 211 to 214 described above
Each of them constitutes a pre-processing step in each stage of wafer processing, and is selected and executed according to a necessary process in each stage.

At each stage of the wafer process, when the above pre-processing step is completed, a post-processing step is executed as follows. In this post-processing step, first, in step 2
In 15 (resist forming step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred onto the wafer by the above-described exposure apparatus and exposure method. next,
In step 217 (development step), the exposed wafer is developed, and in step 218 (etching step), the exposed members other than the portion where the resist remains are removed by etching. Then, in step 219 (resist removing step), unnecessary resist after etching is removed.

By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.

If the above-described device manufacturing method of the present embodiment is used, the above-described exposure apparatus 100 is used in the exposure step (step 216), so that the position control performance of the wafer table 18 (and the XY stage 20) is improved.
Alternatively, if the projection optical system PL has a high N.D.
A. As a result, it is possible to easily manufacture a highly integrated device which has been conventionally difficult to manufacture at low cost.

In the above embodiment, the case where the interferometer is reset at the timing of shifting from the alignment measurement to the exposure operation using the reference plate FP1 or FP2 has been described, but the wafer table 18 as a substrate stage is described. It is sufficient to determine some reference point above, position the wafer table 18 so that this reference point is located at a predetermined reset position, and reset the interferometer. Therefore, one point on the wafer W, for example, an alignment mark attached to one of the shots may be defined as the reference point.

In the above embodiment, the case where the movable mirrors 24X and 24Y are fixed on the wafer table 18 has been described. Alternatively, the side surfaces of the wafer table may be mirror-finished and used as movable mirrors. Is possible,
In this case, the rigidity of the wafer table 18 can be enhanced. When the size of the wafer table can be reduced as in the above-described embodiment, the side surface of the wafer table can be mirror-finished and used as a movable mirror.

In the above embodiment, the so-called EGA
The arrangement coordinates of the shot areas on the wafer W are obtained in advance by measurement, and the method of stepping the wafer table according to the arrangement coordinates at the time of exposure has been described. However, the measurement and exposure of the alignment mark for each shot area have been described. If the small FM (FP2) is used alternately, the interferometer may be reset at the reset position shown in FIGS. 7A and 7B alternately. In this case, the positional relationship between the reference mark 30-3 and each alignment mark, which is indicated by each arrow in FIG. 8, is measured at the time of alignment, and the pattern image of the reticle is exposed at the time of exposure using the result. And the wafer may be superimposed.

In the above embodiment, the case where the main controller has the interferometer reset function has been described. However, the projection exposure method according to the present invention is not limited to such an apparatus.
The present invention can be applied to both a device that constantly controls the position of the substrate stage with the same interferometer, and a device that controls the position of the substrate stage during exposure and alignment measurement with a completely different interferometer.

In the above embodiment, the case where the present invention is applied to a step-and-repeat type projection exposure apparatus has been described. However, the scope of the present invention is not limited to this. The present invention can be suitably applied to a step-and-scan type projection exposure apparatus. In the case of this step-and-scan type projection exposure apparatus, the multipoint EGA in a shot described above
When the orthogonality error or the like is found, for example,
As disclosed in No. 91 or the like, the orthogonality error may be corrected by changing the relative scanning angle between the reticle stage and the wafer stage.

Furthermore, the present invention can be suitably applied not only to a light exposure apparatus such as a stepper, but also to an electron beam exposure apparatus and an X-ray exposure apparatus. For example, the controllability of the stage can be improved, and the cost of a clean room can be reduced by reducing the installation area (so-called footprint).

[0145]

As described above, according to the projection exposure apparatus of the present invention, there is an effect that the control performance of the substrate stage can be improved.

In particular, claims 2, 11, 14, 15, 16
According to the projection exposure apparatus of the invention described in the above, the two-dimensional coordinate position of the substrate stage can be determined both when exposing the mask pattern via the projection optical system and when detecting the mark on the substrate (sensitive substrate) by the mark detection system There is also an effect that it can be managed accurately.

Further, according to the projection exposure apparatus of the third or fourth aspect of the present invention, the high N.P. of the projection optical system is maintained while the substrate stage is kept at a fixed size. There is also an excellent effect that A and large field can be achieved.

According to the projection exposure apparatus according to the fifth and sixth aspects of the present invention, even if the moving mirror and the substrate stage are reduced in size and weight, there is no inconvenience and the mark position can be measured on the entire surface of the sensitive substrate. There is also an effect that the pattern can be exposed through the projection optical system.

Further, according to the projection exposure apparatus of the present invention, there is also an excellent effect that the stabilization of the baseline can be ensured.

Further, according to the projection exposure apparatus of the present invention, there is an effect that the moving mirror and the substrate stage on which the moving mirror is mounted can be further reduced in size and weight.

Further, according to the projection exposure method of the present invention, even if the substrate stage is reduced in size and weight, the mark position measurement and the pattern exposure via the projection optical system can be performed on the entire surface of the substrate without any disadvantage. A projection exposure method is provided that can be performed.

Further, according to the device manufacturing method of the present invention, there is an effect that a highly integrated semiconductor device can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of a projection exposure apparatus according to one embodiment.

FIG. 2 is a schematic perspective view showing components of the apparatus shown in FIG. 1 in the vicinity of a wafer table.

FIG. 3 is a schematic plan view of components of the apparatus shown in FIG. 1 in the vicinity of a wafer table.

FIG. 4A is a diagram showing a state in which a length measurement beam on a length measurement axis Y is maximized within a movement range of a wafer table, and FIG. It is a figure showing the state where a beam becomes the minimum.

5A and 5B are diagrams for explaining a first interferometer reset function using a large FM of a main controller, wherein FIG. 5A shows a state in which a wafer table is at a wafer exchange position, and FIG.
FIG. 4 is a diagram showing a state where the wafer table is at a reset position of the interferometer.

FIG. 6 is an enlarged view of the reference plate of FIG. 1;
(A) is a diagram showing a large FM, and (B) is a diagram showing a small FM.

7A and 7B are diagrams for explaining a second interferometer reset function using the small FM of the main controller, and FIG. 7A illustrates a state where the wafer table is at the reset position of the interferometer on the measurement axis Xa. (B) is a diagram showing a state where the wafer table is at a reset position of the length measurement axis Xe interferometer.

FIG. 8 is a view visually showing a relative positional relationship between a reference mark on a reference plate obtained as a result of alignment measurement and each shot position on a wafer.

FIG. 9 is a view showing a modification of the above embodiment, showing a case where a yawing interferometer is provided as a Y-axis interferometer.

FIG. 10 is a flowchart illustrating an embodiment of a device manufacturing method according to the present invention.

FIG. 11 is a flowchart of a process in step 204 of FIG. 10;

FIG. 12 is a schematic plan view of components of a conventional apparatus near a wafer table.

[Explanation of symbols]

18 Wafer table (substrate stage) 24X, 24Y Moving mirror 26 Interferometer system 28 Main controller (control means, control system) 30-1, 30-2 First fiducial mark 32-1, 32-2 Second fiducial mark 52A , 52B Reticle microscope (Position detecting means, detector) 100 Projection exposure apparatus R Reticle (mask) PL Projection optical system W Wafer (substrate, sensitive substrate) AS Alignment sensor (mark detection system, detector) Y First measuring axis Xe Second measuring axis Xa Third measuring axis FP1 Reference plate FP2 Reference plate

Claims (25)

[Claims] 1. A projection exposure apparatus for exposing an image of a pattern formed on a mask onto a sensitive substrate via a projection optical system, comprising: a substrate stage on which the sensitive substrate is mounted and moves in a two-dimensional plane; A mark detection system provided separately from the projection optical system to detect a mark on the substrate stage or on the sensitive substrate; an interferometer system for managing a two-dimensional coordinate position of the substrate stage; A movable mirror on the substrate stage whose displacement from a reference position is measured by the following formula: a length Lm of the movable mirror, and a center-to-center distance between a projection center of the projection optical system and a detection center of the mark detection system. A projection exposure apparatus, wherein a relationship of Lm <Dw + 2BL is established between BL and a diameter Dw of the sensitive substrate. 2. The method according to claim 1, wherein the interferometer system includes a first measurement axis in a first axis direction which is a direction connecting a projection center of the projection optical system and a detection center of the mark detection system, and a first measurement axis. A second measurement axis in a second axis direction perpendicularly intersecting at a projection center of the projection optical system, and a third measurement axis in a second axis direction perpendicularly intersecting the first measurement axis at a detection center of the mark detection system. The projection exposure apparatus according to claim 1, further comprising at least a length measurement axis. 3. The substrate at a position where a positional relationship between a predetermined reference point on the substrate stage in the projection area of the projection optical system and a predetermined reference point in the projection area of the projection optical system can be detected. The interferometer of the second length measuring axis is reset with the stage positioned, and the second stage is positioned with the substrate stage positioned such that a reference point on the substrate stage is located within a detection area of the mark detection system. 3. The projection exposure apparatus according to claim 2, further comprising control means for resetting an interferometer of three measurement axes. 4. A reference point in a projection area of the projection optical system is a projection center of a pattern image of the mask, and indicates a positional relationship between the projection center of the mask pattern image and a reference point on the substrate stage. 4. The projection exposure apparatus according to claim 3, further comprising a position detection unit that detects the position via the mask and the projection optical system. 5. A reference plate mounted on the substrate stage, wherein a first reference mark and a second reference mark are formed in a predetermined positional relationship; and a first reference mark of the reference plate is used for the mark detection system. The substrate stage is positioned at a predetermined position such that the second reference mark of the reference plate is located in the detection area and the positional relationship between the second reference mark and the predetermined reference point in the projection area of the projection optical system can be detected at the same time. 3. The projection exposure apparatus according to claim 2, further comprising control means for resetting at least one of the interferometer on the second length measuring axis and the interferometer on the third length measuring axis in the state. 6. A reference point in a projection area of the projection optical system is a projection center of a pattern image of the mask, and a positional relationship between the projection center of the mask pattern image and a second reference mark of the reference plate. 6. The projection exposure apparatus according to claim 5, further comprising: a position detecting unit that detects the position of the light beam through the mask and the projection optical system. 7. The control unit according to claim 6, wherein the detection by the mark detection system and the detection by the position detection unit are performed simultaneously with the substrate stage positioned at the predetermined position. 3. The projection exposure apparatus according to claim 1. 8. The control means resets the interferometer on the second measuring axis after the mark detection system finishes measuring the mark on the sensitive substrate, and resets the interferometer on the sensitive substrate via the projection optical system. 6. The projection exposure apparatus according to claim 3, wherein the interferometer of the third measurement axis is reset after the exposure to the light beam is completed. 9. A projection exposure method for exposing an image of a pattern formed on a mask onto a sensitive substrate via a projection optical system, comprising: a predetermined reference point on a substrate stage on which the sensitive substrate is mounted; Detecting a positional relationship with an alignment mark on a sensitive substrate mounted on a stage, after the detection, positioning a predetermined reference point on the substrate stage within a projection area of the projection optical system, Detecting a positional shift of a predetermined reference point on the substrate stage with respect to a predetermined reference point in a projection area of the optical system and a coordinate position of the substrate stage, wherein the detected positional relationship, the detected positional shift and The movement of the substrate stage is controlled based on the detected coordinate position of the substrate stage, and the pattern image of the mask is aligned with the sensitive substrate mounted on the substrate stage. A projection exposure method. 10. A projection exposure method for exposing, via a projection optical system, an image of a pattern formed on a mask to each of a plurality of shot areas on a sensitive substrate, the method comprising: Detecting the positions of the position detection marks of some sample shot areas selected from among them and a predetermined reference point on the substrate stage on which the substrate is mounted, based on the detection result, Calculating the positional relationship between all the shot areas and a predetermined reference point on the substrate stage, and after the calculation, positioning the predetermined reference point on the substrate stage within the projection area of the projection optical system. Detecting a positional shift between a projection center of the pattern image of the mask by the projection optical system and a predetermined reference point on the substrate stage and a coordinate position of the substrate stage. Controlling the movement of the substrate stage based on the calculated positional relationship, the detected positional shift and the detected coordinate position of the substrate stage, and each of the shot areas on the sensitive substrate mounted on the substrate stage. A projection exposure method, wherein the alignment with the pattern image of the mask is performed. 11. A projection optical system for projecting an image of a pattern on a mask onto a substrate; a substrate stage mounted on the substrate and movable in a two-dimensional plane; A mark detection system for detecting a mark formed on a mounted substrate; and a first measurement for measuring a position of the substrate stage in a direction connecting a projection center of the projection optical system and a detection center of the mark detection system. A second major axis for measuring a position of the substrate stage in a direction perpendicular to the first major axis;
A third measuring axis disposed at a predetermined distance in the direction of the first measuring axis with respect to the measuring axis, and measuring a position of the substrate stage in a direction perpendicular to the first measuring axis; An interferometer system comprising: a first image forming apparatus for transferring an image of a pattern of the mask onto a substrate using the projection optical system;
The movement of the substrate stage is controlled using a length measurement axis and the second length measurement axis, and the first length measurement axis and the third length measurement axis are used when the mark is detected by the mark detection system. And a control system for controlling the movement of the substrate stage using the projection exposure apparatus. 12. The third measurement axis cannot be used when the first measurement axis and the second measurement axis are used, and the first measurement axis and the third measurement axis are used. 12. The projection exposure apparatus according to claim 11, wherein the second measurement axis cannot be used when (1) and (2) are used. 13. The control system resets the interferometer on the second measurement axis after the detection of the mark by the mark detection system is completed, and ends the transfer of the pattern using the projection optical system. 13. The projection exposure apparatus according to claim 12, wherein the interferometer of the third measurement axis is reset after the operation. 14. A projection optical system for projecting an image of a pattern of a mask onto a substrate; a substrate stage on which the substrate is mounted and movable in a two-dimensional plane; A mark detection system for detecting a mark formed on a mounted substrate; and a first length measurement connecting a projection center of the projection optical system and a detection center of the mark detection system to measure a position of the substrate stage. An axis, a second length measurement axis perpendicular to the first length measurement axis at the optical axis center of the projection optical system, and a second length measurement axis perpendicular to the first length measurement axis at the detection center of the mark detection system. A projection exposure apparatus comprising: an interferometer system having three measurement axes; and a control system that resets the interferometer on the third measurement axis when the mark is detected by the mark detection system. 15. A projection optical system for projecting an image of a pattern on a mask onto a substrate; a substrate stage on which the substrate is mounted and movable in a two-dimensional plane; A mark detection system for detecting a mark formed on a mounted substrate; and a first length measurement connecting a projection center of the projection optical system and a detection center of the mark detection system to measure a position of the substrate stage. An axis, a second length measurement axis perpendicular to the first length measurement axis at the optical axis center of the projection optical system, and a second length measurement axis perpendicular to the first length measurement axis at the detection center of the mark detection system. A projection exposure apparatus comprising: an interferometer system having three measurement axes; and a control system for resetting the interferometer on the second measurement axis when the mark is present in a projection area of the projection optical system. 16. The apparatus further comprising a detection system for detecting the mark via the projection optical system, wherein the control system is configured to detect the second mark when the detection system detects the mark via the projection optical system. 16. The projection exposure apparatus according to claim 15, wherein an interferometer on a measurement axis is reset. 17. A projection exposure method for transferring a pattern of a mask onto a substrate via a projection optical system, wherein a mark on a substrate stage on which the substrate is mounted and moved is moved between the mask and the substrate. By detecting position information of the substrate stage with respect to the detector by detecting with a detector for positioning, measuring the position of the substrate stage when position information of the substrate stage with respect to the detector is obtained. A projection exposure method, wherein the interferometer is reset. 18. The projection exposure method according to claim 17, wherein the mark on the substrate stage includes a mark on a substrate mounted on the substrate stage. 19. The projection exposure method according to claim 17, wherein the detector detects a mark on the substrate stage via the mask and the projection optical system. 20. A projection exposure method for transferring a mask pattern onto a substrate via a projection optical system, wherein a mark on a substrate stage on which the substrate is mounted and moved is detected via the projection optical system. Calculating position information of the substrate stage with respect to the projection optical system, and resetting an interferometer for measuring the position of the substrate stage when position information of the substrate stage with respect to the projection optical system is obtained. A projection exposure method. 21. A projection exposure method for transferring a pattern of a mask onto a substrate, wherein the substrate stage mounts and moves the substrate using a detector for aligning the mask and the substrate. A position information of the substrate stage is obtained, and an interferometer for measuring the position of the substrate stage is reset when the position information of the substrate stage is obtained. 22. A projection exposure method for transferring a pattern of a mask onto a substrate, comprising: detecting a mark on a substrate stage on which the substrate is mounted and moving to obtain position information of the substrate stage; A projection exposure method for resetting an interferometer for measuring the position of the substrate stage when position information of the substrate stage is obtained. 23. A projection exposure method for transferring a pattern formed on a mask onto a substrate via a projection optical system, comprising: a predetermined reference point on a substrate stage for mounting the substrate; A first step of detecting a relative positional relationship with each of a plurality of shot areas on the substrate mounted on the substrate; and after the first step, detecting a reference point on the substrate via the projection optical system And a third step of aligning each shot area on the substrate with respect to the projection optical system based on the detection results of the first step and the second step. 24. The projection exposure method according to claim 23, wherein the reference point on the substrate stage includes a mark formed on a substrate mounted on the substrate stage. 25. A device manufacturing method, wherein a semiconductor device is manufactured by using the projection exposure method according to claim 17.