JP3360744B2 - Alignment method and scanning exposure apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment method and a scanning exposure apparatus suitable for use in, for example, a projection exposure apparatus of a slit scan exposure system, and more particularly to an alignment method suitable for use in positioning a reticle. is there.

[0002]

2. Description of the Related Art When a semiconductor element, a liquid crystal display element, a thin film magnetic head, or the like is manufactured by a photolithography process, a pattern of a photomask or a reticle (hereinafter collectively referred to as a "reticle") is coated with a photosensitive material. A projection exposure apparatus for transferring onto a (wafer, glass plate, etc.) is used. As a conventional projection exposure apparatus, a step-and-repeat reduction projection type in which each shot area of a wafer is sequentially moved into an exposure field of a projection optical system and a pattern image of a reticle is sequentially exposed on each shot area. An exposure apparatus (stepper) has been frequently used.

FIG. 9 shows a main part of a conventional stepper. In FIG. 9, a wafer W is mounted on a wafer stage WS, and a reference mark plate FM is fixed on the wafer stage WS near the wafer W. Have been. Then, under the exposure light EL from the illumination optical system (not shown), the image of the pattern on the reticle R held on the reticle stage RS is transmitted via the projection optical system PL in a step-and-repeat manner. Each shot area on the wafer W is projected and exposed. At this time, the wafer stage WS includes an XY stage for positioning the wafer W in a plane perpendicular to the optical axis of the projection optical system PL (the orthogonal coordinate system is defined as the X axis and the Y axis), and the wafer stage WS as the projection optical system PL. And a rotary stage (θ stage) for rotating the wafer W, and the like. A moving mirror 73 for reflecting a laser beam for length measurement from an external laser interferometer 74 is mounted on the wafer stage WS.
The coordinate, the Y coordinate, and the rotation angle θ are measured, and the measurement results are supplied to the main control system 75.

Further, two alignment marks (reticle marks) RM1 and RM2 are formed in the vicinity of the pattern area of the reticle R so as to face each other, and are substantially the same as the projected images of the reticle marks RM1 and RM2 projected by the projection optical system PL. At the same interval, reference marks FM1 and FM2 are formed on the reference mark plate FM, respectively. Generally, when exposing the pattern of the reticle R onto the wafer W,
The wafer stage reticle R is previously placed on the reticle stage RS
The alignment devices 76L and 76R are arranged on the reticle marks RM1 and RM2 of the reticle R, respectively.

[0005] Such alignment devices 76L and 7
Using 6R, reticle mark RM1 on reticle R
A method of roughly aligning the RM2 will be described. First, regarding one alignment device 76L,
Exposure light EL from an illumination optical system (not shown) illuminates reticle R via half mirror 77L, and exposure light transmitted through reticle R passes through projection optical system PL to form a reticle mark on reference mark plate FM. An image of RM1 is formed. However, the reference mark plate FM is a glass surface, and the light is not reflected but diffused, so that the reflected light from the reference mark plate FM does not return to the alignment device 76L. On the other hand, of the exposure light transmitted through the half mirror 77L and reaching the reticle R, the exposure light reflected by the reticle mark RM1 is reflected by the half mirror 77L,
The reticle mark R is provided on the slit of the vibration slit plate 81L via the lens 78L, the mirror 79L and the lens 80L.
An image of M1 is formed.

The image of reticle mark RM1 includes a pattern that is long in the direction perpendicular to the plane of FIG.
L vibrates in a direction parallel to the plane of FIG. The exposure light transmitted through the vibration slit plate 81L is
L, mirror 83L and second relay lens 84L,
The photoelectric conversion is performed by the light receiving system 85L, and the photoelectric conversion signal from the light receiving system 85L is supplied to the alignment device 86. The alignment device 86 synchronously detects the photoelectric conversion signal with a signal having the same frequency as the vibration frequency of the vibration slit plate 81L,
The alignment signal obtained as a result is supplied to the main control system 75. The main control system 75 sets the reticle stage R so that the alignment signal becomes a predetermined value (for example, 0).
The position of the reticle R is adjusted via S. This allows
The position of one reticle mark RM1 of reticle R in the X direction is set as a reference position (for example, the center of vibration) of the slit of vibration slit plate 81L.

The other alignment device 76R is
Lens 77L constituting the above-described alignment device 76L
To the light receiving system 85L, and a photoelectric conversion signal from the light receiving system 85R of the alignment device 76R is supplied to the alignment device 86. The alignment device 86 performs alignment detection of the photoelectric conversion signal (the other reticle RM2 of the reticle R and the other vibration slit plate 81).
A signal corresponding to the amount of displacement of the R with respect to the slit) is supplied to the main control system 75. In the main control system 75, the position in the X direction of the other reticle mark RM2 of the reticle R is set to the reference position of the slit of the vibration slit plate 81R.

Reticle marks for measuring the positions of the reticle R in the Y direction and the rotation direction (θ direction) are also formed on the reticle R, and the reticle marks for the Y direction and the θ direction are also aligned. The device is located. Then, for example, the reticle R is scanned obliquely with respect to the X axis and the Y axis via the reticle stage RS.
From the detected marks in the reticle marks in the direction, Y direction or θ direction, the positions of the marks are fixed (locked) by a closed loop servo system using an alignment signal, and the positions of all the reticle marks are sequentially determined. Is fixed, the X direction and the Y direction of the reticle R and θ
A rough alignment of the directions is performed.

In this case, the reference marks FM1, FM2 and other reference marks on the reference mark plate FM are illuminated in advance from the bottom with light having the same wavelength as the exposure light, and their conjugate images are respectively oscillated by the vibrating slit plates 81L, 81R and 81R. By projecting on other vibration slit plates, the vibration slit plates 81L, 8L
The slits of 1R and other vibration slit plates are positioned. Therefore, by positioning the reticle R with respect to the vibration slit plates 81L and 81R and the other vibration slit plates, the reticle R can be aligned with the reference mark plate FM.

Further, in the conventional stepper, if the alignment between the reticle R and the reference mark plate FM is completed, it is not necessary to move the reticle R again. Therefore,
At the time of alignment of the reticle R, it is possible to adopt a structure in which the drive strokes of the reticle R in the X, Y, and θ directions are increased.

[0011]

In recent years, in semiconductor devices and the like, patterns have been miniaturized, so that it is required to increase the resolution of a projection optical system. Methods for increasing the resolution include shortening the wavelength of the exposure light or increasing the numerical aperture of the projection optical system. It is difficult to maintain the imaging performance (distortion, curvature of field, etc.) at a predetermined accuracy over the entire exposure field. Therefore, what is currently being reviewed is a projection exposure apparatus of a so-called slit scan exposure system.

In the projection exposure apparatus of the slit scan exposure type, the reticle and the wafer are relatively synchronously scanned with respect to an illumination area such as a rectangular or arc-shaped illumination area (hereinafter referred to as a "slit illumination area"). Meanwhile, the reticle pattern is exposed on the wafer. Therefore, if a pattern having the same area as that of the stepper method is exposed on a wafer, the exposure field of the projection optical system can be made smaller in the slit scan exposure method than in the stepper method, and the imaging performance in the exposure field can be reduced. Accuracy may be improved. Further, the manufacturing cost of the projection optical system can be reduced, and the slit scan exposure method is advantageous in this respect as well.

In such a projection exposure apparatus of the slit scan exposure type, it is necessary to align the reticle when the reticle is replaced. However, in the slit scan exposure method in which the reticle is driven in a predetermined direction with high accuracy during exposure, it is necessary to mount a reticle interferometer for monitoring the position of the reticle with high accuracy. It is difficult to increase the drive strokes of the reticle in the X direction, the Y direction, and the rotation direction. Therefore, it is difficult to apply the alignment method used in the conventional stepper directly to the projection exposure apparatus of the slit scan exposure system.

In general, a writing error of a reticle mark with respect to an outer shape of a reticle by an electron beam is ± 0.5 mm.
In this case, when the reticle is positioned on the reticle stage based on the outer shape, if the pattern writing area is inclined at the maximum inclination angle with respect to the outer shape of the reticle, the lateral deviation amount of the laser beam of the reticle interferometer Exceeds the allowable value of the amount of lateral displacement at the receiver of the interferometer.
Therefore, without causing a measurement error of the reticle interferometer,
It has been difficult to correct all reticle drawing errors by the conventional alignment method.

Further, an apparatus equipped with such a reticle interferometer can position a reticle at an arbitrary position with high accuracy by open loop control. Therefore, there is a need to develop an alignment method for detecting a reticle mark position at high speed by open-loop control, in contrast to conventional closed-loop control by synchronous detection.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an alignment method capable of aligning a reticle (mask) with high speed and high accuracy in a projection exposure apparatus of a slit scan exposure system. Furthermore, the present invention
Providing a scanning exposure system that can use the alignment method
The purpose is also to provide.

[0017]

According to a first alignment method of the present invention, an illumination area having a predetermined shape with illumination light is provided.
Is illuminated, and a mask (12) on which a transfer pattern is formed is scanned relative to an illumination area (32) of a predetermined shape via a mask stage (10, 11), and the mask (1)
The pattern on the mask (12) is sequentially exposed on the substrate (5) by scanning the substrate (5) relative to the illumination area (32) of a predetermined shape in synchronization with the scanning of (2). Is a method of positioning the mask (12) with respect to the coordinate system (x, y) on the side of the mask stage (10, 11) as a pre-process. First and second having a pattern
A first step of placing the mask (12) on which the positioning marks (28, 27) are formed on the mask stage (10, 11).

Further, according to the present invention, the observation area (20R _ef ) of the image pickup means (20) intersects the two linear patterns on the first positioning mark (28) on the mask (12). Direction, and processing the obtained image data to obtain a coordinate system (x, y) on the mask stage side of the intersection (28a) of the two linear patterns.
A second step of obtaining the coordinates at the step (b), and using the observation area of the imaging means (19) with the second positioning mark (2) on the mask (12).
7) By relatively moving the two linear patterns in a direction intersecting the two linear patterns above and processing the obtained image data, the coordinates of the intersection of the two linear patterns on the mask stage side A third step of obtaining the coordinates in the system (x, y); and the coordinates of the intersection (28a) of the two linear patterns of the first positioning mark (28) and the second positioning mark (27). The mask stage (10, 1) is based on the coordinates of the intersection (27a) of the two linear patterns.
And a fourth step of aligning the mask (12) with respect to the coordinate system on the 1) side.

The second alignment method according to the present invention illuminates an illumination area (32) having a predetermined shape with illumination light,
A mask (12) on which a pattern for transfer is formed is scanned relative to an illumination area (32) of a predetermined shape via a mask stage (10, 11), and synchronized with the scanning of the mask (12). By scanning the substrate (5) relatively to the illumination area (12) having a predetermined shape, a mask stage (5) is used as a pretreatment for exposing the pattern on the mask (12) onto the substrate (5) sequentially. This is a method of positioning the mask (12) with respect to the coordinate system (x, y) on the (10, 11) side, wherein the positioning mark (2) is used as the mask (12).
The mask (12) on which 8) is formed is moved to a mask stage (1).
The coordinates of the first step (FIG. 8A) to be placed on the mask stage (10, 11) and the coordinate system (x, y) on the mask stage (10, 11) side are obtained. the second step of calculating the rotation angle phi ₁ of the mask (12) (FIG. 8
(B)).

When the rotation angle φ ₁ obtained in the second step exceeds a predetermined allowable value, the mask (1) is further added.
3) Take out 2) from the mask stage (10, 11)
Step (FIG. 8B) and mask stage (10, 11)
The a fourth step of rotating a predetermined rotation angle phi ₂ in the direction of the rotation angle obtained in the second step (FIG. 8 (c)), a mask (12) again on the mask stage (10, 11) placed Then, a fifth step of rotating the mask stage (10, 11) in a direction opposite to the rotation direction in the fourth step (FIG. 8E)
And to execute.

In the second alignment method, after the mask (12) is taken out from the mask stage (10, 11), the mask stage (10, 11) is obtained in a fourth step.
Is rotated, but after rotating the mask stage (10, 11), the mask (12) is moved to the mask stage (1).
The alignment can be performed in the same manner in the operation of taking out from (0, 11). This is the third alignment method of the present invention. However, the mask stage (10,
When the mask (12) is taken out of the mask stage (10, 11) after the rotation of the mask stage (10), the rotation direction of the mask stage (10, 11) in the third step and the fifth step is set to the second alignment. The rotation direction is opposite to the rotation direction in the fourth step and the fifth step in the method. Further, also in the fifth step, in the third alignment method, after rotating the mask stage (10, 11), the mask (12) is mounted on the mask stage (10, 11). Further, in the fourth alignment method according to the present invention, a mask stage (10, 11) that can move while holding a mask (12) on which a predetermined pattern is formed, and a mask stage (10, 11) that can move while holding a substrate (5) Prior to exposing the substrate using an exposure apparatus having a substrate stage (2, 3, 4) and a projection optical system (8) for projecting an image of the pattern of the mask onto the substrate, the mask is aligned. A first step of placing the mask on a mask stage, a second step of determining rotation error information of the mask, and a step of determining whether the rotation error information of the mask exceeds a predetermined allowable range. A third step of removing the mask from the stage, a fourth step of rotating the mask stage by a predetermined rotation angle based on the rotation error information obtained in the second step, On the mask stage in which again and a fifth step of placing. Further, in the fifth alignment method of the present invention, the mask stage (10, 10) capable of holding and moving the mask (12) on which the predetermined pattern is formed is provided.
11) an exposure apparatus comprising: a substrate stage (2, 3, 4) movable while holding a substrate (5); and a projection optical system (8) for projecting an image of a mask pattern onto the substrate. Prior to exposing the substrate (5) using the method, a first step of placing the mask on the mask stage and a second step of obtaining rotation error information of the mask in the method of aligning the mask (12) A third step of rotating the mask stage by a predetermined rotation angle based on the rotation error information obtained in the second step when the rotation error information of the mask exceeds a predetermined allowable range; A fourth step of removing the mask from the mask stage after the third step, and a fifth step of rotating the mask stage in a direction opposite to the rotation direction in the third step after the fourth step And this After the fifth step, it is intended to include a sixth step of re-placing the mask on the mask stage. According to a sixth alignment method of the present invention, in the method of aligning a mask, a first step of mounting the mask (12) on the stage (10, 11) and an alignment error of the mask mounted on the stage. A second step of measuring information, a third step of separating the mask from the stage when the alignment error information exceeds a predetermined allowable range, and, after the third step, based on the alignment error information. The method includes a fourth step of relatively moving the mask and the stage, and a fifth step of placing the mask on the stage again after the fourth step. In a seventh alignment method according to the present invention, the mask (12) held on the first stage (10, 11) is moved in a predetermined scanning direction, and the second stage (10) is moved in a direction corresponding to the scanning direction. In a method for aligning the mask prior to scanning and exposing the substrate by moving the substrate (5) held on (2,3,4), the rotation error of the mask is reduced to the first position.
An interferometer (14) for measuring the position of the first stage in a direction orthogonal to the scanning direction by irradiating a measuring beam on a reflecting surface provided on the stage and extending substantially parallel to the scanning direction. The mask is placed on the first stage so as to be kept within a predetermined allowable range where no error occurs. Next, the scanning exposure apparatus of the present invention moves the mask (12) in the first direction,
In a scanning exposure apparatus for scanning and exposing a substrate by moving the substrate in a second direction corresponding to the first direction, a mask stage for holding the mask; Using the reflecting surface (21) provided on the stage, the first stage of the mask stage is used.
First interferometer system (14) for measuring direction information
And a second step of measuring position information of the mask stage in a direction orthogonal to the first direction using a reflecting surface provided on the mask stage and extending substantially parallel to the first direction.
An interferometer system, a transport member (23A, 23B) for mounting the mask on the mask stage, and a second interference before the mask is mounted on the mask stage from the transport member. A control means (22A) for relatively rotating the mask and the mask stage held on the transport member so that a length measurement error does not occur in the measuring system.

[0022]

In the first alignment method of the present invention, when the mask (12) is placed on the mask stage (10, 11), for example, based on the outer shape, the imaging means (20,
The observation region of 19) is set near the intersection of each of the first and second positioning marks (28, 27).
Then, the mask stage (10, 11) is driven to drive the first stage.
When the mask is stepwise scanned in a direction intersecting the linear pattern of the second positioning mark (28, 27), the observation area of the imaging means (20, 19) is moved to the second position, as shown in FIG. Since the linear pattern of the first and second positioning marks (28, 27) intersects, the image data in the observation area is processed to obtain the first and second positioning marks (28, 27), respectively. The coordinates of the intersection of the linear patterns are detected. The positional relationship between the pattern drawn in the mask (12) and the coordinate system (x, y) on the mask stage (10, 11) side is determined from the coordinates of these intersections, and the mask (12) is determined based on the positional relationship.
Of alignment.

According to the second alignment method,
If the mask stage determined from the coordinates of the positioning marks (28) (10, 11) of the coordinate system (x, y) the rotation angle phi ₁ of the mask (12) for exceeds a predetermined allowable value, once The mask (12) is moved to the mask stage (10, 1).
Remove from 1). Then, for example, the mask stage (1
After rotating (0, 11) in the direction of the rotation angle φ ₁ by a rotation angle φ ₂ such as a rotation limit angle, the mask (12) is mounted on the mask stage (10, 11) again. Then, rotate the mask stage (10, 11) in the reverse direction by the rotation angle φ.
After rotating by _{two, the} rotation angle of the mask (12) with respect to the mask stage (10, 11) is measured again.

If the rotation angle still exceeds the allowable value, the mask (12) is removed and the mask stage (1) is removed.
0, 11) is repeated, and when the rotation angle is within the allowable value, the mask stage (10, 11)
, The direction of the drawing area of the mask (12) is adjusted to the coordinate system (x, y) on the mask stage side. Thereby, the mask stage (10, 1
Even when the amount of movement or the rotation angle in the direction orthogonal to the scanning direction in 1) cannot be increased, alignment of the mask (12) can be performed with high accuracy. Note that, after removing the mask (12) from the mask stage (10, 11), the same applies if the mask loader holding the mask (12) is rotated instead of rotating the mask stage (10, 11). .

According to the third alignment method,
First, in a third step, the mask (12) is placed on the mask stage (1).
0, 11) and the mask stage (10, 1)
After rotating 1) in the reverse direction, the mask (12) is taken out. As a result, the rotation angle of the mask (12) becomes substantially an allowable rotation angle. Then, after returning the rotation angle of the mask stage (10, 11) to substantially the original rotation angle, the mask (12) is placed on the mask stage (10, 11).

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the alignment method according to the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a case where a reticle is positioned on a reticle stage by a projection exposure apparatus of a slit scan exposure system. FIG. 1 shows a projection exposure apparatus of the present embodiment,
In FIG. 1, a pattern on the reticle 12 is illuminated by a rectangular illumination area (hereinafter, referred to as a “slit illumination area”) by exposure light EL from an illumination optical system (not shown), and an image of the pattern is projected. The light is projected and exposed on the wafer 5 via the optical system 8. At this time, with respect to the slit-shaped illumination area of the exposure light EL, the wafer 5 is synchronized with the reticle 12 being scanned forward (or backward) at a constant speed V with respect to the plane of FIG. Is scanned at a constant speed V / β (1 / β is a reduction magnification of the projection optical system 8) in a backward direction (or a forward direction) with respect to the paper surface of FIG.

The drive system for the reticle 12 and the wafer 5 will be described. A reticle Y drive stage 10 which can be driven in the Y-axis direction (perpendicular to the plane of FIG. 1) is mounted on the reticle support 9. A reticle minute drive stage 11 is mounted on the reticle Y drive stage 10, and a reticle 12 is held on the reticle minute drive stage 11 by a vacuum chuck or the like. Reticle micro drive stage 1
1 controls the position of the reticle 12 with a very small amount and high precision in the X direction, the Y direction, and the rotation direction (θ direction) parallel to the paper surface of FIG. 1 in a plane perpendicular to the optical axis of the projection optical system 8. Do. A movable mirror 21 is disposed on the reticle minute drive stage 11, and an interferometer 14 disposed on the reticle support 9 is provided.
Thus, the positions of the reticle minute drive stage 11 in the X direction, the Y direction, and the θ direction are constantly monitored. The position information S1 obtained by the interferometer 14 is stored in the main control system 22A.
Is supplied to

On the other hand, a wafer Y-axis drive stage 2 that can be driven in the Y-axis direction is mounted on the wafer support table 1, and a wafer X-axis drive stage 3 that can be driven in the X-axis direction is mounted thereon. And a Zθ-axis driving stage 4 is provided thereon.
The wafer 5 is held on the Zθ axis drive stage 4 by vacuum suction. The movable mirror 7 is also fixed on the Zθ axis driving stage 4 and is provided by an interferometer 13 arranged outside.
The positions of the Zθ axis drive stage 4 in the X, Y, and θ directions are monitored, and the position information obtained by the interferometer 13 is also supplied to the main control system 22A. Main control system 22A
Controls the positioning operation of the wafer Y-axis driving stage 2 to the Zθ-axis driving stage 4 via the wafer driving device 22B and the like, and also controls the operation of the entire apparatus.

In order to establish a correspondence between a wafer coordinate system defined by coordinates measured by the interferometer 13 on the wafer side and a reticle coordinate system defined by coordinates measured by the interferometer 14 on the reticle side, A reference mark plate 6 is fixed near the wafer 5 on the Zθ axis drive stage 4. Various reference marks for alignment are formed on the reference mark plate 6. Among these reference marks, there are reference marks that are illuminated from behind by illumination light guided to the Zθ-axis drive stage 4 side, that is, luminescent reference marks.

Reticle alignment microscopes 19 and 20 for simultaneously observing the reference mark on the reference mark plate 6 and the mark on the reticle 12 are provided above the reticle 12 in this embodiment. In this case, deflecting mirrors 15 and 16 for guiding the detection light from the reticle 12 to the reticle alignment microscopes 19 and 20 are movably arranged, and when the exposure sequence is started, a command from the main control system 22A is also issued. And the mirror driving devices 17 and 1
8, the deflection mirrors 15 and 16 are retracted, respectively. Further, the wafer 5 is provided on the side surface of the projection optical system 8 in the Y direction.
An off-axis alignment device 34 for observing the upper alignment mark (wafer mark) is provided.

Next, a sequence from loading the wafer 5 and the reticle 12 to ending the alignment in the projection exposure apparatus of this embodiment will be described. First, pre-alignment of the reticle 12 is performed on a reticle loader (described later) based on the outer shape. FIG. 2 shows a reticle loader system for transferring the reticle 12 onto the reticle micro-drive stage 11 shown in FIG. 1. The reticle loader shown in FIG.
Reticle arms 23A and 23B and arm rotation shaft 25 connected to these reticle arms 23A and 23B.
And a rotation mechanism 26 for rotating the arm rotation shaft 25. Reticle arms 23A and 23B
The grooves 24A and 24B for vacuum suction are formed on the reticle mounting surface, respectively, and the reticle arms 23A and 23B are supported via an arm rotation shaft 25 so as to be independently rotatable.

When the reticle 12 is loaded, the reticle 12 is transferred to the reticle arm 23A at a position A3 from another reticle transport mechanism (not shown). At this time, the other reticle arm 23B is used, for example, to carry out the reticle used in the previous process. Next, the reticle 12 is placed on the reticle arm 23A by a reticle outline pre-alignment mechanism (not shown) installed near the position A3.
Are aligned with a certain accuracy on the basis of the outer shape, the reticle 12 is vacuum-sucked onto the reticle arm 23A.
Next, the rotation mechanism 26 rotates the reticle arm 23A via the arm rotation shaft 25, and conveys the reticle 12 to a position B3 in the Y direction (the direction of the reticle minute drive stage 11 in FIG. 1).

At this time, the groove 24A for vacuum suction is located in a direction orthogonal to the suction position on the reticle minute drive stage 11 and outside the pattern area of the reticle 12, so that the reticle minute drive stage 11 is moved in the scanning direction. Y
The reticle arm 23A can freely move the reticle 12 in and out of the reticle minute drive stage 11 in a state where the reticle 12 is moved to the front in the direction. When the reticle 12 reaches the reticle minute drive stage 11 (see FIG. 1), the arm rotation shaft 25 moves down in the −Z direction, and the reticle 12 is placed on the vacuum suction surface on the reticle minute drive stage 11. After the delivery is completed, reticle arm 23A retracts. Thereafter, the reticle minute drive stage 11 conveys the reticle 12 in the direction of the position C3. At this time, the reticle arms 23A and 23B are driven independently. For example, by performing reticle loading and reticle unloading simultaneously, the reticle exchange speed is improved.

Next, alignment of the reticle 12 will be performed. The mechanism and operation for that will be described. FIG.
3A shows an arrangement of alignment marks (reticle marks) on the reticle 12, and FIG. 3B shows a slit-shaped illumination area in a region 33R conjugate with the effective exposure field of the projection optical system on the reticle. 32 and the like. Let the scanning direction be the y direction and let the direction perpendicular to the y direction be the x direction. In FIG. 3A, a light-shielding portion 31 is formed around a region on the reticle 12 where a pattern to be transferred is formed, and a reticle mark formed outside the light-shielding portion 31 is used for rough search. Alignment marks 27 and 28
And fine alignment marks 29A to 29D and 3
0A to 30D. The rough search alignment mark 27 on the right side is formed by a linear pattern long in the y direction which is the scanning direction and a cross pattern formed at both ends of the linear pattern. And 27b are formed. The left-side rough search alignment mark 28 is configured symmetrically with the right-side rough search alignment mark 27,
Intersections 28a and 28b are formed at both ends in the y direction.

Further, the fine alignment mark 29 is located between the light-shielding portion 31 on the right side and one of the cross patterns of the rough search alignment mark 27 in the y direction.
A, 29B are formed, and the fine alignment mark 2 is located between the light shielding portion 31 on the right side and the other cross pattern of the rough search alignment mark 27 in the y direction.
9C and 29D are formed. Fine alignment marks 30A to 30D are formed on the left side symmetrically to these fine alignment marks 29A to 29D, and these fine alignment marks 29A to 29D are formed.
3A and 30A to 30D, as shown in FIG. 3C, two sets of three linear patterns are arranged at predetermined intervals in the x direction, and three linear patterns are arranged at predetermined intervals in the y direction. They are arranged in pairs.

After the reticle 12 is mounted on the reticle minute drive stage 11, the rough search alignment mark 28 on the left side in FIG. 3A is referred to as a reticle alignment microscope (hereinafter referred to as "RA microscope") in FIG. )
Detect at 20. FIG. 3B shows the observation areas 19R and 20R of the RA microscopes 19 and 20 on the reticle 12 in this case. When a rough search (rough search) of the reticle 12 is performed, the rough search alignment mark 27 and the 28 indicates observation areas 19R and 20R, respectively.
Out of the region 33R conjugate with the effective exposure field. This is because the rough search alignment marks 27 and 28 need to be large for rough search, but if the exposure field of the projection optical system is enlarged accordingly, the cost will increase. Therefore, the procedure for performing a rough search in this example is shown in FIG.
This will be described with reference to FIG.

FIG. 4A is an enlarged view of the vicinity of one cross pattern of the rough search alignment mark 28, and FIG.
4B is a diagram in which FIG. 4A is reduced, and FIG.
(A) and (b), the width in the x direction and the y direction of the effective field of view 20R _ef square RA microscope 20 as W,
The design value of the sum of the pattern writing error and the installation error with respect to the outer shape of the reticle 12 is defined as ΔR. Therefore, FIG.
As shown in the figure, the intersection 2 of one of the cross patterns of the rough search alignment mark 28 is located in the square area of the width ΔR.
8a is always included. The detection target is the x-coordinate and the y-coordinate of the intersection 28a of the cross pattern. In this example, the reticle minute drive stage 11 is moved in a direction intersecting at 45 ° with two straight lines passing through the intersection 28a of the alignment mark 28. The reticle 12 through the reticle 12 so that the x-axis and y-axis
Obliquely to the axis to scan the field of view 20R _ef of the width W. Then, the reticle x and y coordinates of the fine driving stage 11 when the two straight lines passing through the intersection point 28a during its diagonal scan crosses a reference point within the effective field of view 20R _ef, and the x-coordinate of the intersection 28a Find the y coordinate.

For this purpose, the integer part of a positive real number a is set to IN
As represented by T (a), the search screen number is the number of minimum scanning the area of the square of the width [Delta] R in the effective field of view 20R _ef having a width W becomes {INT (ΔR / W) +1 }.
The number of search screens is obtained in advance. And FIG.
The width ΔR of the effective visual field B5 shown in FIG.
｛IN of width W so that the edges slightly overlap in the direction of 45 ° with respect to the x-axis and the y-axis
T (ΔR / W) +1} effective fields of view A5, B5, C5
‥‥ is set, and the reticle minute drive stage 11 of FIG. 1 is driven in a stepping manner by open loop control,
While set in the effective field of view 20R _ef of each field of view are sequentially FIG. 5 (a), samples the image in each field of view.

As shown in FIG. 4B, at least the width Δ
An intersection 28a of the alignment mark 28 to be searched exists in the search range of R × ΔR, and the alignment mark 28 is sufficiently large with respect to the search range. Accordingly, it can be understood that the coordinates of the intersection 28a of the alignment mark 28 can be detected with the minimum number of screens by stepping the effective field of view in the oblique direction with respect to the alignment mark 28.
The image processing at that time may be one-dimensional image processing on an image signal obtained by adding the scanning lines of all the lines in the captured screen.

FIGS. 5A and 5B show various image signals obtained by adding all the scanning lines in this manner, and FIGS. 5A and 5D show images obtained in the effective field of view A5 of FIG. 4B. 5 (b) and 5 (e) show image signals along the x and y directions of FIG.
FIG. 5B shows an image signal along the x direction and y direction obtained in the effective visual field B5, and FIGS. 5C and 5F show images obtained along the x direction and y direction obtained from the effective visual field C5 in FIG. 4B. Signal. The x coordinate of the intersection 28a is obtained from the image signal of FIG. 5B, and the y coordinate of the intersection 28a is obtained from the image signal of FIG. Similarly, FIG.
The x coordinate and the y coordinate of the intersection 28b of the other cross pattern of the rough search alignment mark 28 shown in FIG.

After the two-dimensional coordinates of the intersections 28a and 28b of the cross pattern at both ends of the alignment mark 28 are detected in this manner, the rough search alignment mark 27 is moved to the observation area of the RA microscope 19, and The two-dimensional coordinates of the intersections 27a and 27b of the cross pattern at both ends of the alignment mark 27 are detected. In this case, however, the portion of the reference mark plate 6 in FIG. 1 where there is no pattern is moved into the exposure field of the projection optical system 8, and the portion where there is no pattern is illuminated from the bottom. The illumination light emitted from the reference mark plate 6 illuminates the rough search alignment marks 27 and 28 from the back side.

In the above sequence, the positional relationship between the rough search alignment marks 27 and 28 with respect to the observation areas 19R and 20R of the RA microscopes 19 and 20 in FIG. 3B, and the alignment mark 2 with respect to the reticle coordinate system.
A rough positional relationship between 7, 28 can be obtained.
In addition, the rough correspondence between the observation regions 19R and 20R of the RA microscope and the wafer coordinate system is based on the reference mark plate 6 shown in FIG.
The measurement can be performed by measuring the upper reference mark with the RA microscopes 19 and 20. Thereby, fine alignment marks 29A to 29D and 30A to 30D,
Approximate alignment (rough alignment) is completed so that a reference mark (described later) on the reference mark plate 6 does not overlap.

In this embodiment, the alignment marks on the reticle 12 are divided into rough search alignment marks and fine alignment marks in order to reduce the lens diameter of the projection optical system 8. If the diameter can be increased, the rough search alignment mark and the fine alignment mark can be used as a common mark. Even in this case, as shown in FIG. 4, the method of searching for alignment marks by stepwise feeding in an oblique direction can be used, and the search for alignment marks can be performed simultaneously by the RA microscopes 19 and 20.

Next, the sequence of the fine alignment will be described, but before that, the detailed configuration of the wafer stage and the reticle stage will be described. FIG. 6 (a)
FIG. 6A is a plan view of the wafer stage. In FIG. 6A, a wafer 5 and a reference mark plate 6 are arranged on a Zθ axis drive stage 4. An X-axis movable mirror 7X and a Y-axis movable mirror 7Y are fixed on the Zθ axis drive stage 4, and have a slit-like shape corresponding to the slit-like illumination area 32 of FIG. The illumination area 32W is illuminated with the exposure light, and the observation areas 19W and 20W are respectively shown in FIG.
It is conjugate with the observation regions 19R and 20R in (b).

The movable mirror 7X has a laser beam LWX and LW _of is irradiated at intervals along the optical path through the reference point of the optical axis and alignment device 34 and each projection optical system is parallel to the X axis IL, movable mirror 7Y is irradiated with two laser beams LWY1 and LWY2 at an interval IL along an optical path parallel to the Y axis. At the time of exposure, the coordinate value measured by an interferometer using the laser beam LWX is used as the X coordinate of the Zθ axis drive stage 4, and the coordinate value Y measured by the interferometer using the laser beams LWY1 and LWY2 as the Y coordinate. Average value of ₁ and Y ₂ (Y
₁ + Y ₂ ) / 2 is used. Further, for example, the rotational direction of the coordinate values Y ₁ and Y ₂ Z.theta axis driving stage from the difference between the 4 (theta
Direction) is measured. Based on those coordinates, the position and rotation angle of the Zθ axis drive stage 4 on the XY plane are controlled.

In particular, in the Y direction, which is the scanning direction, the average value of the measurement results of the two interferometers is used to prevent deterioration in accuracy due to inclination or the like during scanning. Further, the position in the X-axis direction when the off-axis alignment device 34 is used is controlled based on the measurement value of the dedicated interferometer using the laser beam LW _of so that a so-called Abbe error does not occur. is there.

FIG. 6B is a plan view of the reticle stage. In FIG. 6B, a reticle minute drive stage 11 is mounted on a reticle Y drive stage 10 and a reticle 12 is held thereon. Have been. The reticle minute drive stage 11 has a movable mirror 21x for the x-axis.
And two movable mirrors 21y1 and 21y2 for the y-axis are fixed, the movable mirror 21x is irradiated with two laser beams LRx parallel to the x-axis, and the movable mirrors 21y1 and 21y2 are respectively parallel to the y-axis. Laser beams LRy1, LRy2
Has been irradiated.

As in the case of the wafer stage, the coordinate of the reticle micro-drive stage 11 in the y direction is the same as that of the laser beam LR.
The average value (y ₁ + y ₂ ) / 2 of coordinate values y ₁ and y ₂ measured by two interferometers using y 1 and LRy 2 is used. As the coordinates in the x direction, coordinate values measured by an interferometer using the laser beam LRx are used. Further, for example, the rotation amount of the reticle minute drive stage 11 in the rotation direction (θ direction) is measured from the difference between the coordinate values y ₁ and y ₂ .

In this case, as the movable mirrors 21y1 and 21y2 in the y direction, which is the scanning direction, a corner cube type reflection element is used, and the laser beams LRy1 and LRy2 reflected by the movable mirrors 21y1 and 21y2 are reflected mirrors, respectively. The light is reflected back at 39 and 38. That is,
The y-axis interferometer for the reticle is a double-pass interferometer, so that the laser beam does not shift due to the rotation of the reticle micro-drive stage 11. Further, similarly to on the wafer stage, the slit-shaped illumination area 32 and the RA microscope 1 are placed on the reticle 12.
9, 20 observation areas 19R and 20R are arranged.
The reticle 12 and the Zθ axis drive stage 4 shown in FIG. 6A can be observed only from the observation regions 19R and 20R. As described above, the relationship between the reticle 12 and the Zθ-axis drive stage 4 is measured to improve the alignment accuracy during exposure and the rotation accuracy between the reticle 12 and the wafer 5.

Further, as shown in FIG. 6A, the fine alignment marks 29A to 29C of the reticle 12 shown in FIG.
Reference marks corresponding to 29D and 30A to 30D are formed. Then, by observing the reference mark on the reference mark plate 6 and the fine alignment mark of the reticle 12 corresponding to the reference mark with the RA microscopes 19 and 20, the amount of positional deviation between the two marks is obtained, and based on the amount of positional deviation, the reticle 12 High-precision alignment (fine alignment) is performed.

Next, the allowable value of the rotation angle when the reticle 12 of this embodiment is mounted on the reticle minute drive stage 11 will be examined. Therefore, a part of the configuration of an interferometer for measuring the coordinates in the x direction of the reticle minute drive stage 11 on which the reticle 12 is mounted as shown in FIG. 6B will be described with reference to FIG. As shown in FIG.
The polarization beam splitter 70 is irradiated with a P-polarized laser beam LRx from an x-axis interferometer (not shown). The laser beam LRx passes through the joint surface 70a of the polarization beam splitter 70, passes through the quarter-wave plate 71, and enters the x-axis movable mirror 21x in a state of circular polarization. Then, the laser beam LRx reflected by the movable mirror 21x is reflected by the bonding surface 70a of the polarization beam splitter 70 in the state of S-polarized light via the quarter-wave plate 71, and travels to the corner cube 72. The laser beam LRx reflected by the corner cube 72 is reflected by the joint surface 70a of the polarizing beam splitter 70 and
The light enters the movable mirror 21x in a state of circular polarization through the ４ wavelength plate 71.

Thereafter, the laser beam LRx reflected by the moving mirror 21x enters the bonding surface 70a of the polarizing beam splitter 70 in a P-polarized state via the quarter-wave plate 71, and is transmitted through the bonding surface 70a. The LRx is returned to the receiver of the x-axis interferometer (not shown). That is, when the movable mirror 21x is displaced by Δx in the x direction, the optical path length of the laser beam LRx changes by 4 · Δx, so that the x-axis interferometer on the reticle side also operates as a double-pass interferometer. In this case, the distance in the y direction between the midpoint in the y direction between the laser beam LRx emitted from the interferometer and the laser beam LRx returned to the interferometer and the vertex of the corner cube 72 is La, and the distance from the movable mirror 21x is and the distance in the x direction to the vertex of the corner cube 72 and Lb, the distance L _T to the laser beam LRx from being reflected by the movable mirror 21x to transmit the joint surface 70a of the polarization beam splitter 70 passes, the following equation become that way. _{L T = La + Lb (1} )

At this time, as shown in FIG. 7B, the movable mirror 2 is moved with respect to a plane perpendicular to the incident laser beam LRx.
When the 1x reflecting surface is largely rotated at an angle θ about an axis perpendicular to FIG. 7B, the position of the laser beam LRx returned to the interferometer in the y direction becomes an interval ΔL with respect to the case where the angle θ is 0. Just sideways. The interval ΔL can be represented as follows using the above distance L _{T. ΔL ≒ 4 · L T · θ} (2)

[0054] Therefore, when the rotation angle of the movable mirror 21x theta exceeds the allowable value theta _1, the lateral shift amount ΔL of the laser beam LRx incident on the receiver of the interferometer exceeds the predetermined allowable amount,
The reference beam and the laser beam LRx for length measurement do not sufficiently overlap each other, resulting in a length measurement error of the interferometer. In this case, to previously obtain the allowable value theta ₁ of the rotational angle that do not interferometer error in advance, the rotation error of the reticle 12 upon rough alignment of the reticle 12 need not exceed the allowable value theta _1. Further, the case where the movable mirror 21x rotates means that the reticle minute drive stage is rotating when the pattern drawing area of the reticle 12 is rotating with respect to the reticle coordinate system defined by the measurement value of the reticle-side interferometer. 11 is caused by rotating the rotation direction in such a direction as to cancel the rotation angle. Therefore, in order to keep the rotation angle theta of the moving mirror 21x in tolerance theta ₁ below, when the rough alignment of the reticle 12, a rotation angle with respect to the reticle coordinate system of the drawing area of the pattern of the reticle 12 to the allowable value theta ₁ below Need to fit.

In this embodiment, when the reticle 12 is placed on the reticle minute drive stage 11, the rotation angle of the pattern drawing area of the reticle 12 is set to be equal to or less than the allowable value θ _1. The method will be described with reference to FIG. First, as shown in FIG. 8A, in the initial state of reticle loading, the reticle 12 is positioned on the reticle arm 23A on the basis of the outer shape and is vacuum-adsorbed. For convenience of description, the pattern drawing area PA is greatly inclined with respect to the outer shape of the reticle 12. In this case, the x axis is taken in a direction parallel to the laser beam LRx in FIG. 6B, and the y axis is taken in a direction parallel to the laser beams LRy1 and LRy2, and a reticle coordinate system is formed by these x axis and y axis. Then, the inclination of the drawing area PA is changed to a straight line passing through two intersections 27a and 27b at both ends of one rough search alignment mark 27 (or a straight line passing through two intersections 28a and 28b at both ends of the other rough search alignment mark 28). ) And y in the reticle coordinate system
Expressed by the angle of intersection with the axis. In this initial state, x
On parallel to the reticle fine driving stage 11, respectively to the axis and y-axis taking the x _RS-axis and _y-RS-axis.

After that, as shown in FIG. 8B, the reticle 12 is mounted on the reticle minute drive stage 11 by the reticle arm 23A, and then the reticle arm 23A is retracted to the position B3. In this state, the above-described rough alignment is performed on the alignment marks 27 and 28, and y in the reticle coordinate system of the drawing area PA of the reticle 12 is used.
Rotation angle relative to the shaft to measure the (rotational error) phi _1. The rotation angle φ ₁ is obtained, for example, as an angle between a straight line connecting the intersections 27a and 27b on both sides of the alignment mark 27 and the y-axis. For convenience of explanation, it is assumed that the drawing area PA is rotated clockwise with respect to the y-axis.

If the rotation angle φ ₁ exceeds the allowable value θ ₁ , the reticle 12 is once removed from the reticle minute drive stage 11 using the reticle arm 23A as shown in FIG. Next, the reticle minute drive stage 11 is rotated in the direction of the rotation angle φ ₁ by the limit angle φ ₂ of the rotation angle on the mechanism. That, y _RS-axis on the reticle fine driving stage 11 is rotated in the clockwise direction by the limit angle phi ₂ with respect to the y axis. Then, as shown in FIG.
The reticle 12 is mounted on the reticle minute drive stage 11 again using the reticle arm 23A. Therefore, the reticle fine driving stage 11, to rotate in the counterclockwise direction by the limit angle phi ₂ with respect to the y axis, back to the original position. Thus, as shown in FIG. 8E, the angle of the drawing area PA of the reticle 12 with respect to the y-axis of the reticle coordinate system is set to the allowable value θ.
Less than ₁ .

Note that, even in the state of FIG.
Of the drawing area PA with respect to the y-axis of the reticle coordinate system is
Tolerance θ₁8 (c) to 8 (c).
The operation of (e) may be repeated. Reticle micro drive stay
The operation of rotating the page 11 once makes the allowable value θ₁Twice of
Up to a reticle with a rotation error
₁Within. In addition, reticle micro drive
Rotate the stage 11 and restore it n times (n is 2 or less)
By repeating the above, the initial state of the reticle 12
No matter how large the rotation error of the reticle,
The rotation error of the drawing area PA of No. 2 is set to the allowable value θ.₁Fit within
be able to. After that, fine alignment described above
By doing so, the alignment of the reticle 12 is completed.
You.

When the rotation angle φ ₁ of the drawing area PA of the reticle 12 satisfies θ ₁ <φ ₁ ≦ φ ₂ , the reticle minute drive stage 11 is rotated by the mechanical limit angle φ ₂ instead of rotating the reticle minute drive stage 11 by the limit angle φ _2. to, may be rotated by the rotation angle phi ₁ minute of the drawing area PA. As described above, in the present example, the reticle 12 is stepped in the oblique direction and the position of the reticle mark is detected using the image processing system. Therefore, measurement during rough alignment of the reticle of the projection exposure apparatus of the slit scan exposure method is performed. Becomes possible. Further, in this example, the image processing system for fine alignment is also used for rough alignment, and the servo control system necessary for the synchronous detection type alignment system as shown in FIG. 9 is removed, so that the configuration is simplified. Manufacturing costs can be reduced. When the rotation angle of the drawing area of the reticle 12 is out of the allowable range, the reticle 12 is moved to the reticle minute drive stage 11.
The reticle alignment is not performed because the reticle minute drive stage 11 is rotated, and the reticle 12 is mounted again.

[0060] In the above embodiment, as shown in FIG. 8 (b) and (c), after removal of the reticle 12 from the reticle fine driving stage 11 to rotate the reticle fine driving stage 11 by the rotation angle phi ₂ However, after rotating the reticle minute drive stage 11 by −φ ₂ in advance,
The reticle 12 may be taken out. In this case, as an operation corresponding to FIGS. 8D and 8E, the reticle minute drive stage 11 is rotated by the rotation angle φ ₂ to the original state, and then the reticle minute drive stage 11 is rotated.
The reticle 12 is mounted again on the top. Even with this method, the rotation angle of the drawing area of the reticle 12 can be kept within an allowable value.

In the above embodiment, as shown in FIG. 8, when the rotation angle of the pattern writing area PA of the reticle 12 with respect to the reticle coordinate system exceeds an allowable value, the reticle minute drive stage 11 is rotated. However, the reticle 12 may be rotated in the direction opposite to the rotation angle on the side of the reticle arm 23A from which the reticle 12 has been removed.
For this purpose, a rotating mechanism for rotating the reticle 12 on the reticle arm 23A may be separately provided.

For a reticle having a reticle drawing error having the same tendency with respect to the outer shape reference, a rotation error caused by the reticle drawing error is stored in advance, and the reticle minute drive stage is moved in the direction of an axis determined by the rotation error. 11
May be driven. This eliminates the need to remount the reticle on the reticle minute drive stage 11. Further, it is possible to reduce a tracking error caused by shifting the movable mirror 21x little by little in the non-scanning direction during slit scan exposure due to a rotation error.

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

[0064]

According to the present invention , the mask stage is driven obliquely with respect to the observation area of the image pickup means to scan the mask obliquely, so that two straight lines of the positioning mark on the mask are controlled by open loop control. The coordinates of the intersection of the pattern can be measured. Therefore, there is an advantage that mask alignment can be performed at high speed and with high accuracy.

Further, according to the present invention , the mask can be remounted on the mask stage, whereby the alignment of the mask can be performed at high speed and with high accuracy. Further, it is not necessary to increase the stroke at the time of alignment of the mask stage , and it is not necessary to provide a correction mechanism for the length measuring means. According to the present invention, the slip
When using a mask stage to perform scan exposure
Also, move the mask stage and the mask relatively
After placing the mask on the mask stage,
High-speed and high-accuracy mask alignment
Can be. Next, according to the scanning exposure apparatus of the present invention,
The alignment method of the invention can be used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a reticle loader system.

3A is a layout diagram of alignment marks on a reticle, FIG. 3B is a layout diagram showing alignment marks and the like in a region conjugate to the effective visual field of the projection optical system, and FIG. 3C is a fine alignment mark 29A to 29C. It is an enlarged view which shows 30D.

FIG. 4A is an explanatory diagram in a case where rough alignment of a reticle is performed, and FIG. 4B is a diagram in which FIG. 4A is reduced.

FIG. 5 is a waveform diagram showing various image pickup signals obtained from an image pickup device when rough alignment of a reticle is performed.

FIG. 6A is a plan view of a stage on the wafer side, and FIG.
FIG. 3 is a plan view of a stage on the reticle side.

7A is an optical path diagram showing a state of a laser beam between an x-axis interferometer on a reticle stage side and a moving mirror 21x, and FIG. 7B is a moving mirror 21x from the state of FIG. FIG. 6 is an optical path diagram showing a case where the image is rotated.

FIG. 8 is a diagram for explaining an operation of rotating the reticle minute drive stage 11 and remounting the reticle 12 when the pattern drawing area PA of the reticle 12 is inclined with respect to the reticle coordinate system.

FIG. 9 is a configuration diagram of a conventional alignment system for a stepper.

[Explanation of symbols]

Reference Signs List 4 Zθ axis drive stage 5 Wafer 6 Reference mark plate 7 Wafer-side movable mirror 8 Projection optical system 11 Reticle micro-drive stage 12 Reticle 19, 20 Reticle alignment microscope (RA microscope) 21 Reticle-side movable mirror 23A, 23B Reticle arm 27 , 28 Alignment mark for rough search 29A-29D, 30A-30D Fine alignment mark

Continuation of front page (56) References JP-A-4-196513 (JP, A) JP-A-4-18722 (JP, A) JP-A-4-307720 (JP, A) JP-A-5-62871 (JP) JP-A-1-144626 (JP, A) JP-A-4-109251 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 9/00

Claims (14)

(57) [Claims] An illumination area having a predetermined shape is illuminated with illumination light,
A mask on which a pattern for transfer is formed is scanned relative to the illumination area of the predetermined shape via a mask stage, and the illumination area of the predetermined shape is relatively synchronized with the scanning of the mask. By scanning the substrate, as a pretreatment for sequentially exposing the pattern on the mask on the substrate, an alignment method for positioning the mask with respect to the coordinate system on the mask stage side, wherein the mask A first step of mounting a mask on which the first and second positioning marks each having two mutually intersecting linear patterns are formed on the mask stage; The above-mentioned first positioning mark is relatively moved in a direction intersecting each of the two linear patterns, and the obtained image data is Calculating the coordinates of the intersection of the two linear patterns in the coordinate system on the mask stage side, and the second positioning mark on the mask with respect to the observation area of the imaging means. Are relatively moved in a direction intersecting with each of the two linear patterns, and the obtained image data is processed, whereby the coordinates of the intersection of the two linear patterns on the mask stage side are obtained. A third step of obtaining coordinates in a system; coordinates of an intersection of the two linear patterns of the first positioning mark and coordinates of an intersection of the two linear patterns of the second positioning mark. A step of aligning the mask with respect to the coordinate system on the mask stage side based on the following. 2. An illumination area having a predetermined shape is illuminated with illumination light.
A mask on which a pattern for transfer is formed is scanned relative to the illumination area of the predetermined shape via a mask stage, and the illumination area of the predetermined shape is relatively synchronized with the scanning of the mask. By scanning the substrate, as a pretreatment for sequentially exposing the pattern on the mask on the substrate, an alignment method for positioning the mask with respect to the coordinate system on the mask stage side, wherein the mask A first step of placing a mask on which a positioning mark is formed on the mask stage; and a second step of obtaining a rotation angle of the mask with respect to a coordinate system on the mask stage side by obtaining coordinates of the positioning mark. When the rotation angle obtained in the second step exceeds a predetermined allowable value, the mask is further removed from the mask stage. A third step of rotating the mask stage by a predetermined rotation angle in the direction of the rotation angle determined in the second step, and after mounting the mask on the mask stage again, And a fifth step of rotating in a direction opposite to the rotation direction in the fourth step. 3. An illumination area having a predetermined shape is illuminated with illumination light.
A mask on which a pattern for transfer is formed is scanned relative to the illumination area of the predetermined shape via a mask stage, and the illumination area of the predetermined shape is relatively synchronized with the scanning of the mask. By scanning the substrate, as a pretreatment for sequentially exposing the pattern on the mask on the substrate, an alignment method for positioning the mask with respect to the coordinate system on the mask stage side, wherein the mask A first step of placing a mask on which a positioning mark is formed on the mask stage; and obtaining a rotation angle of the mask with respect to a coordinate system on the mask stage side by obtaining coordinates of a preceding positioning mark. And when the rotation angle determined in the second step exceeds a predetermined allowable value, the mask stage is further determined in the second step. A third step of rotating the mask stage by a predetermined rotation angle in a direction opposite to the set rotation angle, a fourth step of taking out the mask from the mask stage, and rotating the mask stage in a direction opposite to the rotation direction in the third step. And a fifth step of placing the mask on the mask stage again after performing the alignment. 4. A mask stage capable of holding and moving a mask having a predetermined pattern formed thereon, a substrate stage capable of holding and moving a substrate, and a projection for projecting an image of a pattern of the mask onto the substrate. Prior to exposing the substrate using an exposure apparatus having an optical system, in a method of aligning the mask, a first step of placing the mask on the mask stage, and rotation error information of the mask A second step of obtaining the mask from the mask stage when the rotation error information of the mask exceeds a predetermined allowable range; and a third step of taking out the mask from the mask stage, based on the rotation error information obtained in the second step. A fourth step of rotating the mask stage by a predetermined rotation angle; and a fifth step of mounting the mask on the mask stage again.
And an alignment method. After wherein said fifth step, an alignment method according to claim 4, further comprising a sixth step of rotating the mask stage in a direction opposite to the rotation direction in the fourth step. 6. A mask stage capable of holding and moving a mask on which a predetermined pattern is formed, a substrate stage capable of holding and moving a substrate, and a projection for projecting an image of a pattern of the mask onto the substrate. A method for aligning the mask prior to exposing the substrate using an exposure apparatus having an optical system, comprising: a first step of placing the mask on the mask stage; and a rotation error of the mask. A second step of obtaining information; and when the rotation error information of the mask exceeds a predetermined allowable range, rotating the mask stage by a predetermined rotation angle based on the rotation error information obtained in the second step. A third step of causing the mask stage to take out the mask from the mask stage after the third step; and, after the fourth step, removing the mask stage in the third step. A fifth step of rotation, in the opposite direction, after the fifth step, an alignment method characterized by including: a sixth step of re-placing the mask on the mask stage. 7. A method for aligning a mask, comprising: a first step of mounting the mask on a mask stage; and a second step of measuring alignment error information of the mask mounted on the mask stage. A third step of separating the mask from the mask stage when the alignment error information exceeds a predetermined allowable range; and after the third step, the mask and the mask stage are separated based on the alignment error information. A fourth step of relatively moving; and a fifth step of placing the mask on the mask stage again after the fourth step. Before wherein said third step, the alignment method according to claim 7, characterized by further comprising the step of moving the stage on the basis of the alignment error information. 9. The alignment method according to claim 7, wherein said relative movement includes movement of said mask on a transfer member for separating said mask from said stage. 10. A substrate held on a first stage is moved in a predetermined scanning direction, and a substrate held on a second stage is moved in a direction corresponding to the scanning direction to scan the substrate. Prior to exposure, in the method of aligning the mask, a rotation error of the mask may be generated by irradiating a measurement surface onto a reflection surface provided on the first stage and extending substantially parallel to the scanning direction. Mounting the mask on the first stage so that the interferometer for measuring the position of the stage in the direction perpendicular to the scanning direction does not cause a length measurement error within a predetermined allowable range. Characteristic alignment method. 11. A cord provided on the first stage.
Interference that irradiates a measuring beam to a reflecting member of the ner cube type
Using a meter, determine the position of the first stage in the scanning direction.
The alignment method according to claim 10, wherein the measurement is performed . 12. The mask and the first stage are relatively rotated so that a rotation error of the mask does not exceed the allowable range, and after the rotation, the mask is placed on the first stage. Claim 10 or
12. The alignment method according to 11 . 13. A scanning exposure apparatus for scanning and exposing a substrate by moving a mask in a first direction and moving the substrate in a second direction corresponding to the first direction, wherein the mask is held. A first interferometer system that measures position information of the mask stage in the first direction using a reflection surface provided on the mask stage; and a first direction provided on the mask stage. A second interferometer system for measuring position information of the mask stage in a direction orthogonal to the first direction using a reflective surface extending substantially parallel to the mask stage, and a transport for mounting the mask on the mask stage member and said before the mask onto the mask stage from the transport member is placed, so that the measurement error <br/> the second interferometer system does not occur, Serial scanning type exposure apparatus provided with the mask held on the transport member, and control means for relatively rotating said mask stage. 14. The scanning exposure apparatus according to claim 13, wherein the reflection surface of the mask stage is a corner cube type reflection member.