JPH10125579A - Scanning exposure equipment - Google Patents

Abstract

(57) [Problem] To maintain a desired shape of a shot area exposed on a photosensitive substrate even when an angle of a moving mirror of an interferometer for measuring a position of a stage changes. SOLUTION: A wafer 5 on a Zθ axis driving stage 4 is exposed to an exposure area 32 in synchronization with scanning of a reticle 12 on a reticle minute driving stage 11 with respect to an illumination area 31.
, The pattern image of the reticle 12 is exposed on the shot area SA on the wafer 5. Zθ
The rotation angle of the movable mirror 7X in the non-scanning direction of the axis driving stage 4 is obtained from the measured values of the two-axis interferometer bodies 13X1 and 13X2, and the rotation angle of the moving mirror 21X of the reticle micro-drive stage 11 in the non-scanning direction is determined by two axes. Interferometer body 14X1, 14X
2, the relative rotation angle between the wafer 5 and the reticle 12 during scanning exposure is corrected based on the rotation angles of the movable mirrors 7X and 21X.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transferring a mask pattern onto a photosensitive substrate during a photolithography process for manufacturing, for example, a semiconductor device, an image pickup device (such as a CCD), a liquid crystal display device, or a thin film magnetic head. More specifically, the present invention relates to a scanning exposure type exposure apparatus such as a step-and-scan method (scanning exposure apparatus).

[0002]

2. Description of the Related Art For example, when manufacturing a semiconductor device, a reticle and a wafer are synchronously scanned with respect to a projection optical system while a part of a pattern on the reticle is projected onto a wafer via a projection optical system. Therefore, a so-called step-and-scan type projection exposure apparatus that sequentially transfers the image of the pattern on the reticle to each shot area on the wafer is used.

In such a step-and-scan method, since a projection optical system with a reduction ratio is usually used, it is necessary to drive the reticle stage and the wafer stage independently at a speed ratio corresponding to the reduction ratio. In addition, since the movement between the shot areas is performed by a stepping method, the mechanism of the stage system is complicated and requires extremely advanced control (for example, see JP-A-7-176468).

Therefore, as shown in FIG. 10, the speed and the position of a stage of a step-and-scan type projection exposure apparatus have conventionally been controlled based on the measured values of a laser interferometer. That is, FIGS. 10 (a1) and (a2)
, An X-axis movable mirror 52X and a Y-axis movable mirror 52Y are fixed to a wafer stage 51 on which a wafer W is mounted, and an X-axis movable mirror 55X and a reticle stage 54 on which a reticle R is mounted. The Y-axis movable mirror 55Y is fixed. If the orthogonal coordinate system of the plane on which the wafer W moves is the X axis and the Y axis, and the scanning direction at the time of scanning exposure is the direction along the Y axis (Y direction), the conventional Y direction for the scanning direction is used.
2 parallel to the moving mirrors 52Y and 55Y
Laser beams 53Y1, 53Y2, and 5 for book measurement
6Y1 and 56Y2 are irradiated, and the moving mirror 5 for the non-scanning direction
Two measurement laser beams 53X and 56X are applied to 2X and 55X, respectively, and the position in the scanning direction (Y coordinate) is measured by a biaxial laser interferometer, and the position in the non-scanning direction (X coordinate). Was measured by a single-axis laser interferometer.

At this time, the Y coordinate in the scanning direction is represented by an average value of a two-axis laser interferometer, and the difference between the two axes of the Y coordinate is used to calculate the wafer stage 51 (wafer W) and the reticle stage 54 (reticle R). ) Is measured, and during scanning exposure, the X coordinate and the Y coordinate of both stages 51 and 54 are in a positional relationship according to the projection magnification, and both stages 51 and 54 are fixed so that the relative rotation angle of both stages is constant. 54
Synchronous scanning was performed. Since the projection optical system of reverse projection is usually used, the scanning directions of the wafer stage 51 and the reticle stage 54 are opposite to each other. Are both in the −Y direction.

That is, if the reflecting surface of the movable mirror is accurately parallel to the X-axis and the Y-axis during scanning exposure, the wafer W moves in the −Y direction with respect to the slit-shaped exposure region 58 by the wafer stage 51. Synchronously, the reticle stage 54 moves the reticle R in the −Y direction with respect to the slit-shaped illumination area 57, and the pattern image of the reticle R is transferred to one shot area on the wafer W.
The shot area exposed as a result is an accurate rectangle like the shot area SAa enlarged in FIG. 10 (a3), and the shot arrangement formed on the wafer W is as shown in FIG.
As shown in (a4), it has a lattice shape arranged along the X axis and the Y axis.

On the other hand, the yaw of the wafer stage 51 causes the movement of the movable mirror 5 as shown in FIG.
When the 2X and 52Y rotate clockwise by the angle θ, the scanning direction of the wafer W is changed to the moving mirror 52 as indicated by the arrow 60b.
The direction along the X-reflecting surface (the direction inclined by an angle θ with respect to the original Y-axis), and the stepping direction of the wafer W in the non-scanning direction is indicated by the moving mirror 52 as indicated by an arrow 61b.
The direction is along the Y reflection surface. In this case, the moving mirror 52
The rotation of the wafer stage 51 is detected by the inclination of Y, and the reticle stage 54 is also rotated by the angle θ in accordance therewith. Therefore, as shown by the arrow 59b in FIG. 10B2, the reticle R is also rotated by the angle θ. , And is scanned in the rotated direction. Therefore, the shot area exposed on the wafer W by the scanning exposure (transfer area of the pattern image of the reticle R) is a rotating rectangular but accurate rectangle as shown by the shot area SAb in FIG. 10B3. In addition, the shot arrangement on the wafer W (see FIG. 10 (b4)) also has a lattice shape (hereinafter, referred to as an "orthogonal lattice shape") that rotates but has an orthogonal arrangement direction.

[0008]

As described above, in the conventional step-and-scan type projection exposure apparatus, the coordinate positions of the wafer stage and the reticle stage are measured by the laser interferometer, and the two axes for the laser interferometer are used. When the orthogonality of the moving mirror was good, the shape of the shot area exposed even if the wafer stage was rotated by yawing was rectangular, and the shot arrangement obtained was also an orthogonal grid.

However, the stage is thermally deformed due to a temperature change of the ambient gas or a temperature rise due to exposure light irradiation, or the movable mirror itself for the laser interferometer is thermally deformed. When the orthogonality of the mirror is deteriorated, the shape of the shot area to be exposed may not be rectangular, and the shot arrangement may not be orthogonal grid. This is mainly because, conventionally, the position of the stage in the scanning direction is measured by a two-axis laser interferometer, and the rotation angle of the stage is obtained from the difference between the obtained measurement values. That is, in the example of FIG. Moving mirror 52Y,
It is considered that this is because the laser beam from the laser interferometer for yawing measurement was applied to 55Y.

More specifically, FIG. 10 (c1) shows a state in which the movable mirror 52X for the non-scanning direction on the wafer stage side, ie, the yaw measurement is not performed, is inclined by the angle θ. In this case, the scanning direction of the wafer W is a direction along the reflecting surface of the inclined movable mirror 52X as shown by an arrow 60c. However, since a change in the rotation angle of the wafer stage is not detected, FIG.
As shown at 0 (c2), the reticle R (reticle stage 54) is scanned in the −Y direction. Therefore, the wafer W
The shot area formed above becomes a parallelogram as shown by the shot area SAc in FIG. 10 (c3), and the shot arrangement (see FIG. 10 (c4)) also becomes a parallelogram.

FIG. 10 (d1) shows a state in which the movable mirror 52Y for the scanning direction on the wafer stage side, that is, the yaw measurement is being performed, is inclined by the angle θ. in this case,
Although the scanning direction of the wafer W is the −Y direction, since a change in the rotation angle of the wafer stage is detected, the reticle R is at an angle with respect to the original Y axis as indicated by an arrow 59d in FIG. Scanning is performed in a state rotated by θ and inclined by an angle θ. Therefore, the shot area formed on the wafer W is the shot area SA in FIG.
As shown by d, the parallelogram is rotated by 90 °, and the shot arrangement (see FIG. 10D4) has the same shape.

The arrangement error of the shot arrangement shown in FIG. 10 (c4) or (d4) is a linear error (first-order error). Therefore, when exposing a layer thereabove, for example, a so-called enhanced global An alignment (EGA) type alignment is performed, a shot arrangement is obtained by statistical processing, and the wafer stage is stepped in accordance with the obtained shot arrangement, whereby the arrangement error can be substantially corrected. However, the shot area SA
When the shape of the shot area is deformed as shown by c and SAd, Y of the slit-shaped exposure area 58 in FIG.
Assuming that the width in the direction is D and the rotation angle of the movable mirror is θ (rad), the image exposed on the wafer W is equivalent to an image laterally shifted by approximately D · θ in the non-scanning direction during scanning exposure. There is a disadvantage of causing image deterioration.

Further, in order to perform exposure by a so-called mix-and-match method, overlapping exposure is performed on a deformed shot area such as the shot areas SAc and SAd by a collective exposure type exposure apparatus such as a stepper. Also,
The one-shot exposure type cannot correct for such a deformed shot shape. Therefore, such a deformed shot area will include a distortion error,
There is a disadvantage that matching accuracy is deteriorated.

Further, not only when the tilt of the movable mirror of the laser interferometer changes, but also when the movable mirror bends in the scanning direction, there is a disadvantage that the shape of the shot area to be exposed is distorted. Was. The present invention in view of such a point,
A first object of the present invention is to provide a scanning exposure apparatus capable of maintaining the shape of a shot area exposed on a photosensitive substrate in a desired shape even when the angle of a moving mirror of an interferometer for measuring the position of a stage changes. The purpose of.

It is a second object of the present invention to provide a scanning type exposure apparatus which can maintain the shape of a shot area exposed on a photosensitive substrate in a desired shape even when the movable mirror has a bend. I do.

[0016]

A first scanning exposure apparatus according to the present invention comprises a mask stage (9 to 11) for moving a mask (12) on which a pattern for transfer is formed, and a photosensitive substrate (9). 5) moving the substrate (5) in a predetermined direction through the substrate stage in a state where the mask is illuminated with illumination light for exposure, the substrate stage being moved along the substrate stage (1-4). Then, by scanning the mask (12) in a direction corresponding to the predetermined direction through the mask stage, a scanning exposure apparatus that sequentially transfers the pattern of the mask (12) onto the substrate (5) is provided. At least one axis substrate-side interferometer (13Y1, 7Y) for measuring the position of the substrate stage in the scanning direction (Y direction), and a non-scanning direction (X direction) orthogonal to the scanning direction of the substrate stage.
The two-axis substrate-side interferometers (13X1, 13X2, 7X) that measure the position of the laser beam at two points along the scanning direction, and the two-axis substrate-side interferometers for the non-scanning direction, Rotation angle correction means (22D, 44R, 44L) for correcting the relative rotation angle between the substrate stage and its mask stage
And

According to the present invention, as shown in FIG. 2, for example, a two-axis interferometer opposed to a non-scanning moving mirror (7X) of a substrate stage for moving a substrate (5). The main body (13X1, 13X2) is arranged, coordinates are determined by the average value of the two axes, and the yaw amount (rotation angle) of the substrate stage in the non-scanning direction is obtained from the difference between the measured values of the two axes. The mask (12) is rotated according to the amount of yawing. At this time, the rotation angle of the mask stage can be obtained, for example, from the difference between the measured values of two-axis interferometers arranged in either the scanning direction or the non-scanning direction.

As a result, for example, FIGS. 3 (c1) to 3 (c4)
As shown in (2), when the angle of the movable mirror (7X) in the non-scanning direction of the substrate stage changes, the substrate (5) and the mask (12) are scanned while being inclined at the same angle. The shot area (SA3) exposed above remains rectangular even when rotated. In addition, for example, FIG.
As shown in (d4), when the angle of the moving mirror (7Y) in the scanning direction of the substrate stage changes, the substrate (5) and the mask (12) are both scanned without tilting. 5) Shot area exposed above (SA4)
Remains a rectangle. That is, according to the present invention, the substrate (5)
Also, since the scanning direction of the mask (12) is always the same, the shape of the shot area exposed on the substrate (5) is maintained at the target shape.

Even if the shape of the shot area becomes the target shape, the shot arrangement is not an orthogonal lattice (a lattice whose arrangement direction is orthogonal) as shown in FIG. 3 (c4) or (d4). . In order to further form the shot array in an orthogonal lattice shape, a further one-axis substrate-side interferometer (13Y2, 7Y) for measuring the position of the substrate stage in the scanning direction at two positions along the non-scanning direction. And a two-axis substrate-side interferometer (13X1, 13X) for the non-scanning direction.
2, 7X) and the two-axis substrate-side interferometer (13Y1, 13Y2, 13Y2) for the scanning direction.
7Y), it is desirable to provide moving direction correcting means (22A, 22B) for correcting the moving direction of the substrate stage based on the difference from the measured value difference (yaw amount).

At this time, if the stepping direction in the non-scanning direction of the substrate stage is corrected using the difference between the yawing amount in the non-scanning direction and the yawing amount in the scanning direction measured by the present invention, for example, FIG. 3 (c4)
Alternatively, the shot arrangement shown in (d4) has an orthogonal lattice shape indicated by a dotted line. Next, a case in which the movable mirror (21X, 21Y) on the mask stage side is inclined to deteriorate the orthogonality will be considered. Also in this case, the position of the movable mirror (21Y) in the scanning direction of the mask stage is measured by a two-axis interferometer as in the conventional example, and the mask stage is moved based on the difference between the measured values of the two axes. By controlling the rotation angle,
The shape of the shot area to be exposed may not be rectangular.

4 (a2) and 4 (b2), and FIGS. 5 (a2) and 5 (b2) show the two-axis interferometer body facing the movable mirror (21Y) for the scanning direction of the mask stage. An example is shown in which a single-axis interferometer main body is arranged so as to face the movable mirror (21X) for the non-scanning direction. FIGS. 4 (a1) and (a2) show an example in which the position of the substrate stage in the non-scanning direction is measured by a two-axis interferometer as in the first scanning exposure apparatus of the present invention. (A) and (a2) show an example in which the position of the substrate stage in the scanning direction is measured by a two-axis interferometer as in the conventional example.

In these cases, FIG. 4 (a2) or FIG.
As shown in (a2), when the movable mirror (21Y) in the scanning direction of the mask stage is inclined by an angle θ with respect to the mask (12), the movable mirror (21Y) becomes parallel to the substrate stage. Arrows (37a, 3a)
As shown in 8a), the mask (12) is scanned while being inclined with respect to the scanning direction of the substrate (5) while the mask (12) is rotated. Therefore, the shape of the shot area (SA5, SA7) to be exposed is a shape obtained by rotating the parallelogram by 90 °. On the other hand, as shown in FIG. 4 (b2) or FIG. 5 (b2),
If the movable mirror (21X) in the non-scanning direction of the mask stage is inclined by an angle θ with respect to the mask (12), the movable mirror (21Y) is scanned so as to be parallel to the substrate stage. As shown by arrows (37b, 38b), the scanning direction of the mask (12) is inclined with respect to the scanning direction of the substrate (5) so that the shot area (SA6,
The shape of SA8) is a parallelogram.

In order to avoid such deformation of the shot area, the second scanning exposure apparatus according to the present invention employs a mask stage (9 to 11) for moving a mask (12) on which a transfer pattern is formed. And a substrate stage (1-4) for moving a photosensitive substrate (5).
In a state where 2) is illuminated with the illumination light for exposure, the substrate (5) is scanned through the substrate stage in a predetermined direction (Y direction) in synchronization with the mask (12) via the mask stage. Is scanned in a direction (Y direction) corresponding to the predetermined direction, thereby sequentially transferring the pattern of the mask (12) onto the substrate (5). Scan direction (X direction)
And a biaxial substrate-side interferometer (13X1, 13X2, 7X) that measures the position of the mask stage at two points along the scanning direction, and scans the position of the mask stage in the non-scanning direction orthogonal to the scanning direction of the mask stage. A two-axis mask-side interferometer (14X1, 14X2, 21) that measures at two points along the direction
X), the measured values of the two-axis substrate-side interferometer, and
Rotation angle correction means (22D, 44R, 44L) for correcting the relative rotation angle between the substrate stage and the mask stage based on the measurement value of the axis-side mask-side interferometer.

According to the present invention, for example, as shown in FIG. 7, the position of the moving mirror (7X) in the non-scanning direction of the substrate stage is measured by the two-axis interferometer, and the position of the mask stage in the non-scanning direction is measured. The position of the movable mirror (21X) is also measured by a two-axis interferometer, and the yaw amount of the substrate stage is obtained from the difference between the two measured values of the movable mirror (7X).
The rotation angle of the mask stage is obtained from the difference between the two measured values of X). Therefore, FIG. 7 (a2) or (b)
As shown in 2), even if either the moving mirror (21Y) in the scanning direction on the mask stage side or the moving mirror (21X) in the non-scanning direction is inclined with respect to the mask (12), the mask (1
The scanning direction of 2) is parallel to the scanning direction of the substrate (5),
The shape of the shot area (SA13, SA14) to be exposed is rectangular even if rotation (shot rotation) occurs.

Next, a third scanning exposure apparatus according to the present invention comprises a mask stage (9 to 11) for moving a mask (12) on which a transfer pattern is formed, and a photosensitive substrate (5). A substrate stage (1 to 4) that moves, and in a state where the mask (12) is illuminated with illumination light for exposure, the substrate (5) is moved through the substrate stage in a predetermined direction (Y direction).
By scanning the mask (12) in the direction (Y direction) corresponding to the predetermined direction through the mask stage in synchronization with the scanning of the mask (1), the mask (1) is placed on the substrate (5).
In the scanning exposure apparatus for sequentially transferring the pattern of 2), the positions of the substrate stage and one of the mask stages (9 to 11) in the scanning direction are set along the non-scanning direction orthogonal to the scanning direction. The first to measure at the location
A two-axis interferometer (14X1, 14Y2, 21Y) and a second two-axis interferometer (14X1) that measures the position of one stage in the non-scanning direction at two positions along the scanning direction of this stage. , 14X2, 21X) and the first 2
The rotation angle of one of the stages is detected based on the difference between the measurement values of the shaft interferometer, and the detection result and the second 2
Moving mirror bending amount calculating means (22A) for calculating the bending amount of the moving mirror (21X) for the second two-axis interferometer based on the difference between the measurement values of the two-axis interferometer. is there.

According to the present invention, for example, a two-axis interferometer (14) is used for measuring the position of the mask stage in the scanning direction.
Y1, 14Y2, 21Y) and a two-axis interferometer (14X1, 14X2, 21X) for position measurement in the non-scanning direction
When the movable mirror (21X) of the interferometer in the non-scanning direction is bent, for example, as shown in FIG. 9, the mask (12) is scanned while bending, and the shot area to be exposed is distorted. there is a possibility. Therefore, when the mask stage is moved in the scanning direction, the difference between the measured values of the two-axis interferometers in the scanning direction is made constant so that yawing of the mask stage does not occur. In this state, if the difference between the measurement values of the two-axis interferometer for the non-scanning direction is monitored, the curved shape of the movable mirror (21X) in the non-scanning direction can be measured. At the time of actual scanning exposure, the mask stage moves linearly in the scanning direction by correcting the measurement value of the two-axis interferometer by the amount of bending of the movable mirror (21X) thus measured. , A shot area closer to a rectangle is exposed.

In each of the scanning exposure apparatuses of the present invention described above, the measurement of the two-axis interferometer for measuring the positions of the substrate stage and one of the mask stages in the non-scanning direction orthogonal to the scanning direction is performed. Monitor the difference between the values, and when the difference thus monitored exceeds a predetermined threshold,
It is desirable to further include a measuring means (6, 19, 20) for measuring a positional relationship between the mask (12) and its substrate stage. The reason why the difference between the measured values of the two-axis interferometer exceeds the predetermined threshold value is considered to be because the tilt angle of the movable mirror for the interferometer has changed significantly due to thermal deformation or the like. At this time, the positional relationship between the mask (12) and the substrate stage is re-measured, whereby the mask (12) and the substrate (5) are measured.
Can be corrected, the shape error of the shot area to be exposed is reduced. In such a case, the bending amount of the moving mirror may also be changed, and therefore, the bending amount of the moving mirror may be measured again.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a scanning exposure apparatus according to the present invention will be described below with reference to the drawings.
In this example, the present invention is applied to a step-and-scan type projection exposure apparatus. FIG. 1 shows a projection exposure apparatus of the present embodiment. In FIG. 1, a rectangular illumination area (hereinafter, referred to as an exposure light EL) from an illumination optical system (not shown) is shown.
The reticle 12 is defined by a “slit-shaped illumination area”.
The upper pattern is illuminated, and an image of the pattern is projected onto the photoresist-coated wafer 5 through the projection optical system 8. In this state, the wafer 5 is scanned in synchronization with the reticle 12 being scanned forward (or backward) at a constant speed V with respect to the paper surface of FIG. Is scanned at a constant speed V / M (1 / M is the projection magnification of the projection optical system 8) backward (or forward) with respect to the paper surface of FIG. The projection magnification (1 / M) is, for example, 1 /
4, 1/5, etc. Hereinafter, the Z axis is taken in parallel with the optical axis AX of the projection optical system 8, and the reticle 12 is set in a plane perpendicular to the Z axis.
And the Y axis in the designed scanning direction of the wafer 5 (ie, the direction perpendicular to the plane of FIG. 1), and the X axis in the non-scanning direction orthogonal to the scanning direction (ie, the direction along the plane of FIG. 1). Take and explain. However, the actual scanning direction may deviate from the direction parallel to the Y axis (Y direction) due to the inclination of the movable mirror of the interferometer for coordinate measurement of the stage system as described later.

Next, the reticle 12 and the stage system of the wafer 5 in this embodiment will be described. First, the reticle support 9
Reticle Y-axis drive stage 10 that can be driven upward in the Y direction
The reticle minute drive stage 11 is placed on the reticle Y-axis drive stage 10, and the reticle 12 is held on the reticle minute drive stage 11 by a vacuum chuck or the like. Reticle micro drive stage 11
Performs position control of the reticle 12 in a small amount and with high accuracy in each of the X direction, the Y direction, and the rotation direction (θ direction). Reticle support 9 and reticle Y-axis drive stage 1
A reticle stage is constituted by 0 and the reticle minute drive stage 11. Reticle micro drive stage 1
A movable mirror 21 is disposed on the reticle 1, and the positions of the reticle minute drive stage 11 in the X, Y, and θ directions are constantly monitored by an interferometer body 14 disposed on the reticle support 9. That is, the interferometer body 14 is actually
The four-axis interferometer bodies 14X1 and 14X shown in FIG.
2, 14Y1 and 14Y2. Interferometer body 1
4 is supplied to the main control system 22A that controls the overall operation of the apparatus. Main control system 22
A controls the operations of the reticle Y-axis driving stage 10 and the reticle minute driving stage 11 via the reticle driving device 22D.

On the other hand, a wafer Y-axis drive stage 2 is mounted on the wafer support table 1 so as to be drivable in the Y direction, and a wafer X-axis drive stage 3 is mounted thereon so as to be drivable in the X direction. A Zθ axis driving stage 4 is provided thereon, and a wafer 5 is held on the Zθ driving stage 4 by vacuum suction. The Zθ axis drive stage 4
It controls the position of the direction, the tilt angle, and the minute rotation angle. The wafer stage is composed of the wafer support 1, the wafer Y-axis drive stage 2, the wafer X-axis drive stage 3, and the Zθ-axis drive stage 4. The movable mirror 7 is also fixed on the Zθ axis drive stage 4, and the interferometer body 1 disposed outside
3, the position of the Zθ axis drive stage 4 in the X direction, Y axis direction and θ direction is monitored, and the position information obtained by the interferometer main body 13 is also supplied to the main control system 22A. That is, the interferometer body 13 is also actually a four-axis interferometer body 13X1, 13X2, 13Y1, 13Y2 shown in FIG.
Collectively. The main control system 22A includes the wafer driving device 2
The positioning operation of the wafer Y-axis drive stage 2, the wafer X-axis drive stage 3, and the Zθ-axis drive stage 4 is controlled via 2B.

As will be described later, the wafer coordinate system defined by the coordinates measured by the interferometer body 13 on the wafer stage side and the interferometer body 14 on the reticle stage side
In order to correspond to a reticle coordinate system defined by the coordinates measured by the above, a reference mark plate 6 on which a predetermined reference mark is formed in the vicinity of the wafer 5 on the Zθ axis drive stage 4 is fixed. Among the reference marks, there is also a reference mark illuminated from the bottom surface side by the illumination light guided into the inside of the Zθ axis drive stage 4, that is, a luminescent reference mark.

Reticle alignment microscopes 19 and 20 for simultaneously observing the reference mark on the reference mark plate 6 and the alignment mark on the reticle 12 are arranged above the reticle 12 in this embodiment. In this case, the detection light from the reticle 12 is respectively transmitted to the alignment microscope 1
Deflection mirrors 15 and 16 for guiding to 9 and 20 are movably arranged, and when an exposure sequence is started, the deflection mirrors 15 and 18 are respectively driven by mirror driving devices 17 and 18 under a command from the main control system 22A. And 16 are saved. Further, an off-axis type alignment sensor 34 for detecting the position of an alignment mark (wafer mark) on the wafer 5 is disposed on a side surface of the projection optical system 8 in the Y direction. A console 22C for inputting commands from an operator and displaying measurement data is connected to the main control system 22A.

Next, the configuration of the interferometer (interferometric length measuring device) for the stage system of this embodiment will be described with reference to FIG. FIG.
2A is a plan view showing the reticle micro-drive stage 11 shown in FIG. 1, and FIG. 2B is a view showing Zθ on the wafer stage side shown in FIG.
FIG. 2A is a plan view showing the axis driving stage 4. In FIG. 2A, a reticle 12 is held on a reticle fine movement stage 11 by vacuum suction or the like, and a slit-shaped illumination region 31 elongated in the X direction on the reticle 12. Exposure light is being emitted.

Since the reticle 12 (reticle minute drive stage 11) is scanned in the Y direction, the reticle minute drive stage 11 is formed of parallel flat glass at the end in the + X direction of the reticle minute drive stage 11 extending in the scanning direction (Y direction). The movable mirror 21X is installed, and the movable mirror 2 is moved from the interferometer bodies 14X1 and 14X2.
The 1X reflection surface is irradiated with measurement laser beams (measurement beams) LRX1 and LRX2 in parallel in the Y direction at an interval L1. The interferometer bodies 14X1 and 14X2 each include a reference mirror, a movable mirror 21X and a receiver for receiving interference light of a laser beam from the reference mirror, and a signal processing unit for processing a photoelectric conversion signal from the receiver. The X-coordinate of the reflection surface of the movable mirror 21X can be detected by processing the photoelectric conversion signal from the receiver. The movable mirror 21X accelerates the reticle 12,
At the time of deceleration, both measurement beams LRX1 and LRX2 are
It is formed long enough not to deviate from 1X. Further, the measurement beams LRX1 and LRX2 are at the center of the slit-shaped illumination area 31 (the optical axis AX of the projection optical system 8).
, The measurement values of the interferometer bodies 14X1 and 14X2 are XR1 and XR2, respectively, and the position of the reticle 12 in the non-scanning direction as an average value of these measurement values (XR1 and XR2) X coordinate) XR
Is detected, and the difference between the measured values is divided by the interval L1 to detect the rotation angle θ _{RX of} the reticle 12 viewed from the non-scanning direction. That is, the following equation holds.

XR = (XR1 + XR2) / 2 (1) θ _RX = (XR1−XR2) / L1 (2) The movable mirror at the end of the reticle minute drive stage 11 in the + Y direction at an interval L2 in the X direction. Corner cubes 21Y1 and 21Y2 are fixed, and the interferometer body 14 is
From Y1 and 14Y2, measurement beams LRY1 and LRY2 are emitted in parallel along the scanning direction. In addition, the measurement beams LRY1 and LRY2 reflected by the corner cubes 21Y1 and 21Y2 are respectively reflected to interferometer main body 1
Fixed plane mirrors 14M1 and 14 returning to the 4Y1, 14Y2 side
M2 is arranged, and the interferometer main bodies 14Y1 and 14Y2 are respectively provided with corner cubes 21Y1 and 21Y2 by a double-pass interference method.
The Y coordinate of 1Y2 is detected. The reticle 12 has a narrow moving range in the X direction, and has a corner cube 21Y1,
Since the position can be accurately detected in a range in which the measurement beams LRY1 and LRY2 fall on the incident surface of 21Y2, the corner cube 21 is used as a movable mirror in the scanning direction.
Y1, 21Y2 can be used.

The measurement beams LRY1 and LRY2 are also distributed centrally symmetrically in the X direction with respect to the center (optical axis AX) of the illumination area 31, and the interferometer bodies 14Y1 and 14Y
Reticle 1 by the average of the measured values YR1 and YR2
2, the position (Y coordinate) YR in the scanning direction is detected. The rotation angle θ _{RY of the} reticle 12 viewed from the scanning direction is detected by dividing the difference between the measured values by the interval L2. The difference between the rotation angle θ _RY viewed from the scanning direction and the rotation angle θ _RX viewed from the non-scanning direction is the orthogonality error ΔωR between the movable mirror 21X and the corner cubes 21Y1, 21Y2.
Becomes That is, the following equation holds.

YR = (YR1 + YR2) / 2 (3) θ _RY = (YR1-YR2) / L2 (4) ΔωR = (YR1-YR2) / L2- (XR1-XR2) / L1 (5) Is the rotation angle (the amount of yawing) of the reticle 12 based on the rotation angle θ _{RX as} viewed from the non-scanning direction in equation (2).
Is corrected. Therefore, the reticle minute drive stage 1
1, two actuators 44R and 44L are installed on the end surface in the -Y direction, and the actuators 44R and 44L displace the reticle minute drive stage 11 with respect to the reticle Y axis drive stage 10 of FIG. Reticle micro-drive stage 11 (reticle 1
It is configured such that the rotation angle of 2) can be controlled. The operations of the actuators 44R and 44L are controlled by the reticle driving device 22D shown in FIG. However, as described later, when monitoring the amount of bending of the movable mirror 21X,
The rotation angle of the reticle 12 is controlled based on the rotation angle θ _RY viewed from the scanning direction in equation (4).

In FIG. 2A, a two-axis laser interferometer for the non-scanning direction is constituted by the movable mirror 21X and the interferometer main bodies 14X1 and 14X2.
The 1Y2, the fixed plane mirrors 14M1 and 14M2, and the interferometer main bodies 14Y1 and 14Y2 constitute a two-axis laser interferometer for the scanning direction. Then, the interferometer body 14X1,
A coordinate system consisting of an X coordinate XR measured by 14X2 and a Y coordinate YR measured by the interferometer bodies 14Y1 and 14Y2 is defined as a coordinate system (XR, Y) of the reticle stage.
R). Although this coordinate system may be somewhat different from an ideal rectangular coordinate system in design consisting of the X axis and the Y axis, the reticle 12 is based on the coordinate system (XR, YR) of the reticle stage. Driven.

Next, in FIG. 2B, a wafer 5 is held on the Zθ axis driving stage 4 by vacuum suction or the like, and a reference mark plate 6 is fixed near the wafer 5. Two rows of luminescent reference marks 46A to 46F are formed on the reference mark plate 6 along the scanning direction, and two rows of alignment marks 45A to 45F are also formed on the reticle 12.
45F is formed. By detecting both marks by the alignment microscopes 19 and 20 in FIG. 1, the correspondence between the coordinate system of the reticle stage and the coordinate system of the wafer stage is obtained. The details are also disclosed in, for example, JP-A-7-176468.

The reticle 12 is placed on the slit-shaped exposure area 32 conjugate with the illumination area 31 on the reticle on the wafer 5.
Is projected, and the wafer 5 is scanned in the Y direction with respect to the exposure region 32, thereby the wafer 5 is scanned.
The pattern of the reticle 12 is transferred to the upper one shot area SA. At the end of the Zθ axis driving stage 4 in the −X direction, a movable mirror 7X made of a parallel plate glass extending in the scanning direction (Y direction) is installed.
The movable mirror 7Y made of a parallel plate glass extending along the non-scanning direction so as to be orthogonal to the movable mirror 7X at the end in the -Y direction.
Has been fixed. The measuring surfaces LWX1 and LWX2 are irradiated in parallel in the Y direction on the reflecting surface of the movable mirror 7X from the interferometer main bodies 13X1 and 13X2, and X is applied to the reflecting surface of the moving mirror 7Y from the interferometer main bodies 13Y1 and 13Y2.
Measurement beams LWY1 and LW parallel to each other at an interval L4
Y2 has been irradiated.

The movable mirrors 7X and 7Y scan and expose the wafer 5,
Alternatively, it is formed long enough so that the corresponding measurement beam does not come off during stepping. Further, the measurement beams LWX1 and LWX2 are arranged in a slit-shaped exposure region 3.
2 are arranged in the Y direction with respect to the center of 2 (optical axis AX), and the interferometer main bodies 13X1 and 13X
The position (X coordinate) XW of the wafer 5 in the non-scanning direction is detected based on the average value of the measurement values XW1 and XW2 of the wafer 2, and the average value of the measurement values YW1 and YW2 of the interferometer main bodies 13Y1 and 13Y2 is used in the scanning direction of the wafer 5. The position (Y coordinate) YW is detected. The yaw amount (rotation angle) θ _{WX of the} wafer 5 is detected by dividing the difference between the measurement values XW1 and XW2 by the interval L3, and the rotation angle θ _WY obtained by dividing the difference between the measurement values YW1 and YW2 by the interval L4. And the difference between the yaw angle θ _WX and the yaw angle θ _WX , the orthogonality error ΔωW between the movable mirrors 7X and 7Y is detected. That is, the following equation holds.

XW = (XW1 + XW2) / 2 (6) YW = (YW1 + YW2) / 2 (7) θ _WX = (XW1-XW2) / L3 (8) ΔωW = (YW1-YW2) / L4- (XW1-XW2 ) / L3 (9) In FIG. 2B, the moving mirror 7X and the interferometer body 13X
1, 13X2, a two-axis laser interferometer for the non-scanning direction is constructed, and the movable mirror 7Y and the interferometer main bodies 13Y1, 13Y
2 constitutes a two-axis laser interferometer for the scanning direction. Thus, the X coordinate XW measured by the interferometer main bodies 13X1 and 13X2, and the interferometer main bodies 13Y1 and 13Y
A coordinate system including the Y coordinate YW measured by Y2 is referred to as a coordinate system (XW, YW) of the wafer stage. This coordinate system may be somewhat different from an ideal rectangular coordinate system in design consisting of the X axis and the Y axis. However, the scanning and stepping of the wafer 5 are performed by the coordinate system (XW , YW). For example, when the correction of the orthogonality error ΔωW in Expression (9) is not performed, the stepping direction of the Zθ-axis driving stage 4 (wafer 5) is the scanning direction along the reflecting surface of the movable mirror 7X (X coordinate XW is In the non-scanning direction, the direction is the direction along the reflecting surface of the movable mirror 7Y (the direction in which the Y coordinate YW does not change).

Next, the basic operation of the projection exposure apparatus of this embodiment when performing alignment, scanning exposure, and stepping will be described. First, the reference mark plate 6 shown in FIG.
Is used to perform reticle alignment. That is, the wafer Y-axis drive stage 2 and the wafer X-axis drive stage 3 of FIG.
2A, the reference marks 46A and 46B of the reference mark plate 6 are moved into the exposure area 32 of the projection optical system 8 and stopped, and the reticle Y-axis drive stage 10 is driven to drive the reticle shown in FIG. Alignment mark 4 on 12
5A and 45B are moved into the illumination area 31. Then, the alignment microscopes 19 and 20 shown in FIG.
The reticle Y-axis drive stage 10 and the reticle minute drive stage 11 are detected by detecting the amount of positional deviation from the reference marks A and 45B, and the amount of positional deviation between the alignment marks 45A and 45B is symmetric with respect to the images of the reference marks 46A and 46B. Adjust so that it becomes. Thereby, the position and the rotation angle of the reticle 12 are aligned with the reference mark plate 6. In this state, for example, the reticle stage side 4
By resetting the measurement values of the three-axis interferometer body 14 and the four-axis interferometer body 13 on the wafer stage side, the reticle stage coordinate system (XR, YR) and the offset of the origin between the wafer stage coordinate system (XW, YW) determined by the equations (6) and (7) are corrected.

In addition, the scanning direction of the Zθ axis driving stage 4 on the wafer stage side during the scanning exposure is made parallel to the arrangement direction of the reference marks on the reference mark plate 6 in advance. For this purpose, as an example, the reference marks 46A, 46C, 4
The arrangement direction of 6E may be parallel to the reflection surface (running surface) of the movable mirror 7X. However, when a mechanical adjustment error remains, each time the Y coordinate YW of the wafer stage changes by a predetermined step, the X coordinate XW is changed by a corresponding amount, so that the Zθ axis drive stage 4 may be corrected. Hereinafter, the coordinate system in which the scanning direction corrected in this way is the Y axis is referred to as the coordinate system (XW, YW) of the wafer stage.

Next, the stage on the wafer stage side and the stage on the reticle stage side are synchronously scanned in the same manner as in the scanning exposure without irradiating the exposure light, and the reference marks 46C to 46F on the reference mark plate 6 are used. The relative displacement between the corresponding alignment marks 45C to 45F on the reticle 12 is sequentially detected by the alignment microscopes 19 and 20. From the average value of these relative displacement amounts, the inclination angle between the scanning direction of the reticle 12 and the scanning direction of the wafer 5, that is, the coordinate system (XR, Y
R) and the rotation angle of the axis in the scanning direction between the wafer stage coordinate system (XW, YW). Thereafter, when the reticle 12 is scanned, the X coordinate XR is laterally shifted by a corresponding amount while the Y coordinate YR changes by a predetermined interval via the reticle Y axis drive stage 10 and the reticle minute drive stage 11, thereby making the software The scanning direction of the reticle 12 is matched with the arrangement direction of the reference marks on the reference mark plate 6. Hereinafter, the coordinate system having the scanning direction corrected in this manner as the Y axis is referred to as the coordinate system (XR, Y
R). As a result, the coordinate system (X
W, YW) and the reticle stage coordinate system (XR, Y
In (R), axes in the scanning direction are parallel to each other with reference to the reference mark plate 6, and the reticle 12 and the wafer 5 are scanned in parallel during scanning exposure.

In this case, the movement of each stage is based on the guide surface of each stage.
For example, the parallelism between the guide surface of the reticle Y-axis drive stage 10 and the guide surface of the wafer Y-axis drive stage 2 is several hundreds.
It is mechanically adjusted to about μrad or less. Further, by fixing the movable mirror and the reference mark plate 6 together on the guide surfaces, the amount of software correction by driving each stage also in the non-scanning direction during scanning exposure is reduced, and the control accuracy is reduced. Has been improved. When the reticle 12 is actually mounted on the reticle micro-drive stage 11 adjusted as described above, when the reticle 12 is set on the basis of the outer shape or the like, the alignment of the reticle 12 with respect to each movable mirror and the reference mark plate 6 is performed. There is a possibility that only the marks 45A to 45F are largely rotated. This is because when the positional deviation between the outer shape of the reticle and the transfer pattern is large, it is about 0.5 mm.

If the displacement between the outer shape of the reticle 12 and the transfer pattern shown in FIG. 2A is large, the displacement between the alignment marks 45A to 45F of the reticle 12 and the reference marks 46A to 46F of the reference mark plate 6 is increased. Is measured such that the reticle 12 or the reference mark plate 6 relatively rotates or has a large offset. However, the reference mark plate 6 is provided with the movable mirrors 7X and 7X.
Since it is fixed in accordance with the running of Y, the correction is performed by rotating or shifting the reticle minute drive stage 11. Here, when the reticle minute drive stage 11 is rotated, the movable mirror 21X also rotates in the same manner, so that the movable mirror 21X is inclined with respect to the running direction of the reticle 12, but the alignment marks 45A to
45F is a reference mark 46A to 46F on the reference mark plate 6.
The scanning direction is controlled so that the running direction of the reticle 12 and the running direction of the wafer 5 are parallel during scanning exposure.

Next, wafer alignment is performed to determine the arrangement of each shot area on the wafer 5 on the coordinate system (XW, YW) of the wafer stage. As an example, a predetermined number of shot areas (sample shots) selected from on the wafer 5 using the alignment sensor 34 of FIG.
The coordinates of all the shot areas on the wafer 5 are calculated by the EGA (Enhanced Global Alignment) method that measures the coordinates of the wafer mark of the above and statistically processes the measurement result. In addition, an interval (baseline amount) between the detection center of the alignment sensor 34 and a reference point in the exposure area 32 of the projection optical system 8 is obtained in advance by a so-called baseline check using the reference mark plate 6. It is stored in the control system 22A. Therefore, the array coordinates of each shot area on the wafer 5, the baseline amount of the alignment sensor 34, and the coordinate system (XW, Y
Based on the relationship between W) and the coordinate system (XR, YR) of the reticle stage, the shot area to be exposed on the wafer 5 is positioned at the scanning start position, and the reticle 12 is also positioned at the corresponding position.

Thereafter, the scanning exposure operation is performed in accordance with the coordinate system (XW, YW) of the wafer stage and the coordinate system (XR, YR) of the reticle stage determined at the time of the previous reticle alignment. 7X, 7
Y, 21X and the reflecting surfaces of the corner cubes 21Y1, 21Y2 have been corrected by software based on the software.
When the position is relatively shifted from the position, the shape of the shot area and the shot arrangement are affected. In this example, scanning exposure and stepping are performed by the following method so that an accurate rectangular shot area and an orthogonal lattice shot arrangement are formed even in such a case.

That is, the coordinates of the reticle stage coordinate system (XR, YR) when the shot area to be exposed and the reticle are aligned by wafer alignment are (XR ₀ , YR ₀ ) and the coordinate system of the wafer stage. (XW, Y
If the coordinates of (W) are (XW ₀ , YW ₀ ), since the projection magnification of the projection optical system 8 is 1 / M, the reticle minute drive stage 11 (reticle 12) and the Zθ axis drive stage 4 (wafer) The synchronization errors ΔX and ΔY in the scanning direction with respect to 5) and in the non-scanning direction can be expressed as follows. However,
These synchronization errors are errors converted on the reticle 12. Although the projection optical system 8 in FIG. 1 is a reverse projection system,
As shown in FIG. 2, since the measurement directions of the interferometer on the reticle stage side and the interferometer on the wafer stage side are reversed, the synchronization error can be obtained simply by taking the difference between the magnification correction values of the movement amount.

ΔX = (XW−XW ₀ ) · M− (XR−XR ₀ ) (10) ΔY = (YW−YW ₀ ) · M− (YR−YR ₀ ) (11) In this example, (8) ), The rotation angle θ _{WX of the} Zθ axis drive stage 4 as viewed from the non-scanning direction, and the rotation angle θ _RX of the reticle micro-drive stage 11 as expressed by formula (2) as viewed from the non-scanning direction. The difference is defined as a synchronization error Δθ in the rotation direction as follows.

Δθ = θ _WX −θ _RX = (XW1−XW2) / L3− (XR1−XR2) / L1 (12) During scanning exposure, the reticle Y-axis drive stage 10 and wafer Y-axis drive stage in FIG. 2 starts acceleration, and after each of them reaches a predetermined scanning speed, drives the reticle minute drive stage 11 so that the above-mentioned synchronization errors ΔX, ΔY, and Δθ become 0, respectively, to perform synchronization control. After a predetermined settling time has elapsed in this state, irradiation of exposure light on the illumination area 31 on the reticle 12 is started, and exposure is performed.

Thereafter, when the stepping of the wafer 5 is performed in order to expose the next shot area, even if the orthogonality of the movable mirrors 7X and 7Y on the wafer stage side is deteriorated, the shot arrangement is changed to an orthogonal grid ( The stepping direction in the non-scanning direction of the Zθ-axis driving stage 4 is changed so that the orthogonality error Δω of the equation (9) is maintained so as to maintain the shape of a lattice in which the arrangement directions are orthogonal.
Correct by W.

Further, when the orthogonality error ΔωW in the equation (9) or the orthogonality error ΔωR in the equation (5) greatly changes beyond a predetermined allowable value, the other off-axis type alignment sensor 34 Problems may have occurred in the accuracy of the baseline amount and its mechanical stability. Therefore, when the orthogonality error ΔωW or ΔωR greatly changes beyond a predetermined allowable value, the above-described reticle alignment and measurement of the baseline amount are performed again when the wafer is replaced. Thereby, the overlay accuracy of the reticle pattern and each shot area of the wafer can be improved.

Next, a specific example of the shape of a shot area obtained by performing scanning exposure with the projection exposure apparatus of this embodiment and a shot arrangement will be described. First, a case where the orthogonality of the movable mirror on the reticle stage side shown in FIG. 2 is good and the inclination of movable mirrors 7X and 7Y on the wafer stage side shown in FIG. 2 will be described with reference to FIG.

FIGS. 3 (a1) to 3 (d1) show the moving mirror 7 on the Zθ axis driving stage 4 on which the wafer 5 of FIG. 2 (b) is mounted.
FIGS. 3 (a2) to 3 (d2) show the movable mirror 21X and the corner cubes 21Y1, 21Y2 on the reticle micro-drive stage 11 on which the reticle 12 of FIG. 2 (a) is mounted. The corner cubes 21Y1 and 21Y2 are collectively referred to as one movable mirror 21Y. Also, the projection optical system 8 of FIG.
In FIG. 2, the movable mirror 7Y on the wafer stage side is moved to + Y with respect to FIG.
The movable mirror 21X on the reticle stage side is fixed on the −X direction side. As a result, the scanning directions of the wafer 5 and the reticle 12 are the same direction (−Y direction or + Y direction). This is the same in FIGS. 4 to 7 described below.

In FIG. 3, it is assumed that the contour of the pattern area of the reticle 12 is parallel to the reflecting surface of the movable mirror 21X or 21Y. Further, one measurement beam LWY is provided to the scanning direction movable mirror 7Y on the wafer stage side.
1 is irradiated, and one measurement beam LRX1 is irradiated to the non-scanning direction movable mirror 21X on the reticle stage side. This is because during scanning exposure,
This means that the rotation angle of the movable mirror 7Y for the scanning direction is not monitored on the wafer stage side, and the rotational angle of the movable mirror 21X for the non-scanning direction is not monitored on the reticle side. However, the rotation angle of the movable mirror 21X for the non-scanning direction is normally monitored on the reticle side as described above, but the movable mirrors 21X and 21Y on the reticle stage side are described later.
When the orthogonality is good, the same result can be obtained by monitoring the rotation angle of either moving mirror. Therefore, in FIG. 3, the rotation angle of the moving mirror 21Y for the scanning direction is monitored. In this case, instead of the synchronization error Δθ in equation (12), (8)
The rotation angle of the reticle minute drive stage 11 is corrected so that the synchronization error Δθ ′ of the following equation, which is the difference between the wafer rotation angle θ _WX of the equation and the reticle rotation angle θ _RY of the equation (4), becomes zero. .

Δθ ′ = θ _WX −θ _RY (13) As shown in FIG. 3 (a1), the movable mirrors 7X and 7 of the Zθ axis drive stage 4 on the wafer stage side during the scanning exposure.
When the orthogonality of Y is good and the movable mirror 7X is parallel to the Y axis of the ideal orthogonal coordinate system (the movable mirror 7X is parallel to the X axis), the synchronization of the above equation (10) is performed during scanning exposure. Error Δ
Since the scanning is performed such that X, the synchronization error ΔY of the equation (11), and the synchronization error Δθ ′ of the equation (13) become 0, respectively, as shown in FIG. The reticle 12) is scanned with respect to the illumination area 31 in parallel with the Y axis. In addition, since the shot area SA1 on the wafer 5 is also scanned in parallel with the Y-axis with respect to the exposure area 32, the shape of the shot area SA1 is as shown in FIG.
It is an accurate rectangle as shown enlarged. Further, the stepping direction of the Zθ axis driving stage 4 on the wafer stage side when moving from one shot area to the next shot area is parallel to the X axis and the Y axis, so that the shot formed on the wafer 5 The array is a rectangular lattice as shown in FIG.

Next, as shown in FIG. 3B1, during scanning exposure, the orthogonality of the movable mirrors 7X and 7Y on the wafer stage side is good, and the Zθ axis driving stage 4 rotates clockwise by an angle θ. Then, the wafer 5 is scanned at an angle θ with respect to the Y axis as shown by an arrow 34b. In addition, since the reticle minute drive stage 11 (reticle 12) is also scanned while rotating clockwise by the angle θ, the shape of the shot area SA2 on the wafer 5 is rotated as shown in FIG. Is an exact rectangle. Further, the stepping direction of the Zθ axis driving stage 4 on the wafer stage side is a direction along the reflecting surface of the movable mirror 7Y as indicated by an arrow 35b in the scanning direction and a direction indicated by an arrow 35b in the non-scanning direction. The shot array formed on the wafer 5 is rotated, as shown in FIG.

On the other hand, as shown in FIG. 3 (c1), when the angle of the movable mirror 7X in the non-scanning direction on the wafer stage side changes by θ as compared with FIG.
Is scanned at an angle θ with respect to the Y axis as shown by an arrow 34c, and the reticle 12 is also moved to an arrow 33 in FIG. 3 (c2).
As shown by c, scanning is performed at an angle θ with respect to the Y axis. As a result, as shown in FIG. 3C3, the shape of the shot area SA3 exposed on the wafer 5 remains rectangular. However, at this time, the movable mirrors 7X, 7
When the stepping is performed along Y, since the orthogonality error of the movable mirrors 7X and 7Y occurs, the shot arrangement on the wafer 5 becomes a parallelogram as shown in FIG.
It is no longer an orthogonal grid. On the other hand, in this example, FIG.
As shown by the dotted line in (c1), the moving mirror 7Y is further irradiated with a one-axis measurement beam LWY2, and the stepping direction of the non-scanning direction of the Zθ-axis driving stage 4 (wafer 5) is expressed by Expression (9). Is corrected by the orthogonality error ΔωW. That is, the stepping direction of the non-scanning direction of the wafer 5 is as shown in FIG.
As shown by the arrow 47c in (c1), the movable mirror 7Y is rotated clockwise by the angle θ. Therefore, the shot arrangement on the wafer 5 is represented by the dotted grid 48 in FIG.
As shown in FIG. 3 (c), it is rotating but has an orthogonal lattice shape.

On the other hand, as shown in FIG.
When the angle of the movable mirror 7Y in the scanning direction on the wafer stage side changes counterclockwise by θ as compared with (a1), the wafer 5 is scanned in the −Y direction. Also, since the tilt angle of the movable mirror 7X is not used for correcting the rotation angle of the reticle 12,
The reticle 12 is also scanned in the −Y direction as shown in FIG. 3D2, and the shape of the shot area SA4 exposed on the wafer 5 remains rectangular as shown in FIG. 3D3. Also in this case, if the stepping is simply performed on the wafer side along the movable mirrors 7X and 7Y, the shot arrangement on the wafer 5 becomes an arrangement such that the parallelogram is rotated by 90 ° as shown in FIG. 3 (d4). Become. Actually, in this example, the stepping direction in the non-scanning direction of the wafer 5 is the orthogonality error Δ
Since the correction is made by ωW, the stepping direction in the non-scanning direction of the wafer 5 is rotated clockwise by the angle θ with respect to the movable mirror 7Y as shown by an arrow 47d in FIG. Therefore, the shot arrangement on the wafer 5 is as shown in FIG.
As shown by a dotted grid 48d in (d4), an accurate orthogonal grid is formed.

FIG. 3 shows a case where the rotation angle of the reticle 12 is corrected based on the rotation angle of the movable mirror 21Y for the scanning direction. However, in this example, the rotation angle of the reticle 12 is usually the one for the non-scanning direction. Is controlled based on the rotation angle of the movable mirror 21X. FIG. 6 shows a case where the rotation angle of the reticle 12 is corrected based on the rotation angle of the non-scanning direction movable mirror 21X. In FIG. 6, the movable mirror 21X has two measurement beams LRX1, 3 is the same as FIG. 3 except that LRX2 is irradiated and the movable mirror 21Y is irradiated with only one measurement beam LRY1. Also in FIG. 6, since the rotation angle of reticle 12 is corrected according to the tilt angle of moving mirror 7X in the non-scanning direction on the wafer stage side, when the orthogonality of moving mirrors 7X and 7Y on the wafer stage side is good. (FIGS. 6 (a1) and (b1)), the scanning direction of the reticle 12 becomes parallel to the scanning direction of the wafer 5 (FIG.
2), (b2)), exposed shot areas SA9, S
The shape of A10 is rectangular (FIG. 6 (a3), (b)
3)), the shot arrangement to be formed is also an orthogonal lattice (FIGS. 6 (a4) and (b4)).

Further, even if the moving mirror 7X in the non-scanning direction on the wafer stage side is inclined (FIG. 6 (c1)) and the scanning direction of the wafer 5 is inclined as shown by the arrow 40c, the scanning direction of the reticle 12 is also shown. 6 (c2) is tilted as indicated by an arrow 39c, so that the shape of the shot area SA11 to be exposed is rectangular (FIG. 6 (c3)). Further, even if the movable mirror 7Y in the scanning direction on the wafer stage side is tilted (FIG. 6 (d1)), the scanning directions of the wafer 5 and the reticle 12 are parallel to the Y axis (FIG. 6 (d2)), and the exposure is performed. The shape of the shot area SA12 is rectangular (FIG. 6 (d3)). Also in this case, simply stepping along the moving mirrors 7X and 7Y of the wafer stage, the resulting shot arrangement is as shown in FIGS. 6 (c4) and (d4).
As shown in the figure, it is no longer an orthogonal lattice, but actually (9)
Since the stepping direction in the non-scanning direction of the wafer 5 is corrected by the orthogonality error ΔωW in the expression, and the wafer 5 is stepped in the direction of the arrow 41c or the arrow 41d, a shot arrangement in an orthogonal lattice is obtained.

Next, the moving mirror 21 on the reticle stage side
The case where the orthogonality is deteriorated due to the inclination of X and 21Y will be described with reference to FIGS. 4, 5 and 7. FIG. First, for comparison with the actual operation in this example, FIG. 4 shows a case where the orthogonality of the movable mirrors 21X and 21Y on the reticle stage side is further deteriorated in the configuration of FIG. FIG. 5 shows a case where the orthogonality of the movable mirror is deteriorated.

As shown in FIG. 4A2, when the movable mirror 21Y in the scanning direction on the reticle stage side is inclined by the angle θ, the movable mirror 21Y is perpendicular to the movable mirror 7X in the non-scanning direction on the wafer stage side. Rotation correction is performed. Then, even if the wafer 5 is scanned in parallel to the Y axis (see FIG.
1)), since the reticle 12 is rotated obliquely along the movable mirror 21X so that the coordinates of the reticle stage in the non-scanning direction do not change while rotating as shown by the arrow 37a, the exposure on the wafer 5 is performed. The shot area SA5 to be obtained has a shape obtained by rotating the parallelogram by 90 ° (see FIG. 4A
3)). Further, as shown in FIG. 4B2, when the movable mirror 21X in the non-scanning direction of the reticle stage is inclined by the angle θ, the movable mirror 21Y maintains the state orthogonal to the movable mirror 7X in the non-scanning direction on the wafer stage side. Is done. Then, even if the wafer 5 is scanned parallel to the Y axis (FIG. 4 (b1)), the reticle 12 is scanned obliquely along the movable mirror 21X as shown by an arrow 37b, so that the reticle 12 is exposed on the wafer 5. Shot area SA6 becomes a parallelogram (see FIG. 4B
3)). Also, regarding the shot arrangement on the wafer 5,
Since the movable mirrors 7X and 7Y on the wafer stage side are orthogonal to each other, the mirrors are in an orthogonal lattice shape without any correction (FIGS. 4 (a4) and (b4)).

FIG. 5 shows a conventional technique, that is, a case where the rotation angle of the reticle 12 is corrected based on the rotation angle of the movable mirror 7Y in the scanning direction on the wafer stage side in the configuration of FIG. Also in this case, since the rotation angle of the Zθ axis drive stage 4 (wafer 5) is detected in the same manner as in FIG. 4, the shape of the obtained shot area is not rectangular. That is, as shown in FIG. 5A2, when the movable mirror 21Y in the scanning direction on the reticle stage side is inclined by the angle θ, even if the wafer 5 is scanned parallel to the Y axis (FIG. 5A1), 12 is rotated as indicated by the arrow 38a and is scanned obliquely along the movable mirror 21X, so that the shot area SA7 to be exposed has a shape obtained by rotating the parallelogram by 90 ° (FIG. 5 (a3)). ). Further, as shown in FIG. 5B2, when the moving mirror 21X in the non-scanning direction on the reticle stage side is inclined by the angle θ, the wafer 5 is scanned in parallel with the Y axis (FIG. 5B1). , Reticle 12 is arrow 3
8b, the shot area SA8 to be exposed is a parallelogram (see FIG. 5B
3)). Also in this case, the shot arrangement on the wafer 5 has an orthogonal lattice shape (FIGS. 5A4 and 5B).
4)).

As described above, when the rotation angle of the reticle minute drive stage 11 (reticle 12) is corrected on the reticle stage side based on the rotation angle of the movable mirror 21Y in the scanning direction, the orthogonality of the movable mirrors 21X and 21Y is reduced. The shape of the shot area obtained when the image quality deteriorates is not rectangular. In order to avoid this, in this example, as described with reference to FIG. 2A, the rotation angle of the reticle minute drive stage 11 is normally determined based on the rotation angle of the movable mirror 21X in the non-scanning direction of the reticle minute drive stage 11. Has been corrected.

FIG. 7 shows a case where the rotation angle of the reticle 12 is corrected based on the rotation angle of the movable mirror 21X in the non-scanning direction on the reticle stage side as in the normal operation of the present example, and FIG. 7 (a2). As shown in (2), even if the movable mirror 21Y in the scanning direction on the reticle stage side is inclined by the angle θ, this inclination angle is not used for rotation correction of the reticle 12. Therefore,
When the wafer 5 is scanned in parallel with the Y axis (see FIG.
1)), since the reticle 12 is also scanned in parallel with the Y axis,
The shot area SA13 to be exposed is rectangular (FIG. 7).
(A3)). On the other hand, as shown in FIG. 7B2, when the movable mirror 21X in the non-scanning direction of the reticle stage is inclined by the angle θ, the rotation of the reticle 12 is adjusted so that the movable mirror 21X is parallel to the movable mirror 7X of the wafer stage. Correction is performed. That is, when the wafer 5 is scanned in parallel with the Y axis (FIG. 7B1), the reticle 12 is scanned in parallel with the Y axis while being rotated by the angle θ, so that the shot area SA14 to be exposed is rotated. It is rectangular, although it does (Figure 7)
(B3)). Also in this case, the shot arrangement on the wafer 5 has an orthogonal lattice shape (FIGS. 7A4 and 7B4).
4)).

As described above, according to this embodiment, since the rotation angle of reticle 12 is corrected based on the rotation angle of movable mirror 7X in the non-scanning direction of the wafer stage, movable mirrors 7X and 7Y on the wafer stage side. 6 (or FIG. 3), the scanning directions of the wafer 5 and the reticle 12 are maintained in parallel, and the shot area exposed on the wafer 5 is Is kept rectangular. Further, also on the reticle stage side, since the rotation angle of the reticle 12 is corrected based on the rotation angle of the moving mirror 21X in the non-scanning direction, as shown in FIG. Even when the inclination is generated and their orthogonality is deteriorated, the scanning directions of the wafer 5 and the reticle 12 are kept parallel, and the shape of the shot area exposed on the wafer 5 is kept rectangular. Further, since the stepping direction of the wafer stage in the non-scanning direction is corrected based on the orthogonality error ΔωW of the equation (9), even if the orthogonality of the movable mirrors 7X and 7Y of the wafer stage deteriorates, Are arranged in an orthogonal lattice.

However, even if the shot arrangement is in the form of an orthogonal lattice, for example, as shown in FIG. 7B2, when the movable mirror 21X in the non-scanning direction of the reticle stage is inclined with respect to the pattern of the reticle 12, As shown in FIG. 7B4, rotation (shot rotation) occurs in each shot area. In order to prevent the occurrence of such shot rotation, the orthogonality error ΔωR of the moving mirror of the reticle stage of the above-described equation (5) is constantly monitored, and whether or not the orthogonality error ΔωR is an error allowable for shot rotation. What is necessary is just to put the sequence which determines whether it is in the exposure sequence. If the orthogonality error ΔωR
Is out of the allowable range, the reference mark plate 6 on the wafer stage is moved to the exposure area of the projection optical system 5 at the time of wafer exchange or again during shot exposure, and reticle alignment is performed. Coordinate system (X
R, YR) is reset, and the subsequent shot rotation can be prevented.

When there is a possibility that a shot rotation has already occurred, a so-called multipoint EG within a shot is used.
The rotation angle of each shot area on the wafer 5 may be measured by performing the A-type alignment. That is, in the intra-shot multi-point EGA system, as shown in FIG.
) Two-dimensional wafer marks MR and ML are formed in advance. At the time of alignment, for example, four shot areas are selected as sample shots 43A to 43D from all shot areas on the wafer 5, and the sample shots 43 are used by using the alignment sensor 34 in FIG.
The coordinates of a plurality of wafer marks MR and ML in A to 43D are measured. When this result is statistically processed, for example, an average shot rotation of each shot area on the wafer 5 is obtained from an average value obtained by dividing a shift amount of the Y coordinate of the wafer marks MR and ML by an interval in the X direction. Can be Therefore, when overlay exposure is performed on the wafer 5, the overlay error can be reduced by rotating the reticle in advance by the shot rotation.

Next, in the above embodiment, the bending of the movable mirror 21X in the non-scanning direction on the reticle stage side is negligible, but, for example, the positioning accuracy of the stage will be improved and the scanning distance of the reticle stage will be reduced. When it becomes longer, it is desirable to correct the bending of the movable mirror 21X in the non-scanning direction. Accordingly, an example of a method of measuring the bending of the movable mirror 21X and an example of a correction method will be described below with reference to FIG.

FIG. 9A shows the reticle minute drive stage 11 shown in FIG. 2A. In FIG. 9A, the corner cubes 21Y1, 21 as moving mirrors in the scanning direction are shown.
The respective Y coordinates YR1 and YR2 of Y2 are measured by the measurement beams LRY1 and LRY2, and the X coordinates XR1 and XR2 of the moving mirror 21X in the non-scanning direction are measured by the measurement beams LRX1 and LRX2. At this time, the reticle minute drive stage 11 (reticle 12)
Rotation angle θ _{RX as} seen from the non-scanning direction of equation (2)
Instead, the rotation angle θ _RY (= (YR
1-YR2) / L2). Then, while the rotation angle of the reticle minute drive stage 11 is fixed such that the rotation angle θ _{RY in the} scanning direction is, for example, 0, the reticle minute drive stage 11 is moved in the Y direction, more precisely, for example, in the non-scanning direction. The scanning is performed until the one X coordinate XR1 of the mirror 21X becomes a constant value to the state shown in FIG. 9B, and the Y coordinate YR (= (YR1 + Y
R2) / 2) is a predetermined sample coordinate YRn (n = 1,
(2,...), The difference ΔXD between the X coordinates XR1 and XR2 at the two positions of the movable mirror 21X is obtained and stored. X coordinate XR at the n-th (n = 1, 2, 3,...) sample point
Assuming that XR1 and XR2 are XR1n and XR2n, the n-th difference ΔXDn is as follows.

ΔXDn = XR1n−XR2n (14) At this time, since the yawing of the reticle minute drive stage 11 is sequentially corrected, the difference ΔXDn is purely bending information of the movable mirror 21X, and In the Y coordinate YRn, the difference ΔXD
n and the Y coordinate Y between them
In R, by interpolating the amount of bending before and after, the Y
The amount of bending of the movable mirror 21X is obtained as a function FD (YR) of the coordinates YR, and is stored in the main control system 22A of FIG. The bending amount of the movable mirror 21X may be obtained as a function of the Y coordinate YR using a spline function or the like.

That is, since the number n of the difference ΔXDn is finite, it is necessary to perform interpolation between the measurement points. At the time of interpolation, when the sampling interval is small, proportional distribution may be used. However, when the sampling interval is large, the accuracy of correction can be increased by curve approximation or interpolation using a spline function. Thereafter, when performing scanning exposure, the X coordinate X measured by the movable mirror 21X of the reticle minute drive stage 11 is used.
For example, by adding the bending amount FD (YR) of the movable mirror 21X to R (= (XR1 + XR2) / 2), the accurate X of the reticle minute drive stage 11 in which the bending amount of the movable mirror 21X is corrected. The coordinates are determined.
By using the corrected X coordinate, the reticle minute drive stage 11 (reticle 12) is linearly scanned, so that the shape of the shot area exposed on the wafer becomes an accurate rectangle. The measurement and correction of the bending of the movable mirror can be applied to the movable mirror on the wafer stage side.

In the above-described embodiment, the rotation angle is obtained from the difference with the average value of the measured values of the two interferometer bodies as the position. The rotation angle may be obtained from the difference between the position and the measurement value of the other interferometer body. That is, one interferometer main body may be used for position measurement, and the other interferometer main body may be used for yawing measurement. Further, the two interferometer bodies do not necessarily need to be arranged symmetrically with respect to the exposure area or the like. Further, as each laser interferometer, any one of a single-pass system, a double-pass system, and a system in which the optical path is folded many times may be used. Further, the method of measuring the bending of the movable mirror on the reticle stage side can naturally be applied to the measurement of the bending of the movable mirror on the wafer stage side.

In the above embodiment, the laser interferometer having two axes in the scanning direction and two axes in the non-scanning direction is arranged on the wafer stage. However, for example, when it is not necessary to correct the shot arrangement, , The laser interferometer in the scanning direction may be one axis. Further, in order to increase the averaging effect when obtaining the position and the rotation angle of the wafer stage, a laser interferometer having three or more axes may be arranged in the scanning direction and the non-scanning direction. Similarly, on the reticle stage side, if it is not necessary to measure the bending amount of the movable mirror in the non-scanning direction, the laser interferometer in the scanning direction may be one axis. Further, in order to increase the averaging effect when obtaining the position and rotation angle of the reticle stage, a laser interferometer having three or more axes may be arranged in the scanning direction and the non-scanning direction.

Further, the present invention can be applied to various exposure apparatuses for independently measuring the coordinates of the reticle stage and the wafer stage. 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.

[0079]

According to the first scanning type exposure apparatus of the present invention, the relative rotation between the substrate stage and the mask stage based on the measurement value of the two-axis substrate-side interferometer for the non-scanning direction of the substrate stage. Since the angle is corrected, even when the angle of the movable mirror of the substrate-side interferometer changes, the substrate stage and the mask stage are scanned in parallel. Therefore,
There is an advantage that the shape of the shot area exposed on the photosensitive substrate can be maintained in a desired shape (rectangular or the like). For this reason, image deterioration due to distortion of the shape of the shot area and a matching error with the exposure apparatus using the batch exposure method are reduced.

At this time, a further one-axis substrate-side interferometer for measuring the position of the substrate stage in the scanning direction at two points along the non-scanning direction is provided, and a two-axis substrate-side interferometer for the non-scanning direction is provided. In the case where moving direction correction means for correcting the moving direction of the substrate stage based on the difference between the measurement value of the meter and the difference between the measurement values of the two-axis substrate-side interferometer for the scanning direction is provided. For example, by correcting the stepping direction in the non-scanning direction of the substrate stage, the shot arrangement formed on the photosensitive substrate can be made into an orthogonal lattice. Thereby, the overlay error is further reduced.

According to the second scanning type exposure apparatus of the present invention, the measurement values of the biaxial substrate side interferometer in the non-scanning direction of the substrate stage and the biaxial mask side of the mask stage in the non-scanning direction are used. Since the relative rotation angle between the substrate stage and the mask stage is corrected based on the interferometer, the substrate stage and the mask stage are parallel even if the angle of the moving mirror of the mask-side interferometer changes. Is scanned.
Therefore, there is an advantage that the shape of the shot area exposed on the photosensitive substrate can be maintained in a desired shape (rectangular or the like).

Further, according to the third scanning type exposure apparatus of the present invention, the rotation angle of one stage is detected based on the difference between the measurement values of the first two-axis interferometer of one stage, and this detection is performed. Since the bending amount of the movable mirror for the second two-axis interferometer is calculated based on the result and the difference between the measurement values of the second two-axis interferometer, yawing occurs on the stage. Can accurately detect the amount of bending of the movable mirror. Therefore, during actual scanning exposure, the stage is scanned while correcting the amount of bending of the movable mirror, so that the stage can be accurately scanned in a desired direction. Can be maintained in a desired shape.

In these cases, the difference between the measured values of the two-axis interferometer for measuring the positions of the substrate stage and one of the mask stages in the non-scanning direction orthogonal to the scanning direction exceeds a predetermined threshold value. In this case, when a measuring means for measuring a positional relationship between the mask and the substrate stage is further provided, there is an advantage that a shape error of a shot region on the photosensitive substrate is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an embodiment of a scanning exposure apparatus according to the present invention.

2A is a plan view showing an arrangement of an interferometer on a reticle stage side of the projection exposure apparatus of FIG. 1, and FIG. 2B is a plan view showing an arrangement of an interferometer on a wafer stage side of the projection exposure apparatus of FIG. FIG.

FIG. 3 is an explanatory view showing a shape of a shot area and a shot arrangement when the tilt of a movable mirror on the wafer stage side changes in the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a shape of a shot area and a shot arrangement when the tilt of a moving mirror on the mask stage side changes in the configuration of FIG. 3;

FIG. 5 is an explanatory diagram showing the shape of a shot area and the shot arrangement when the tilt of a moving mirror on the mask stage side changes with the same configuration as in the related art.

FIG. 6 is an explanatory diagram showing a shape of a shot region and a shot arrangement when a rotation angle is measured by a two-axis interferometer in a non-scanning direction even on the mask stage side with respect to the configuration in FIG. 3;

FIG. 7 shows that the tilt angle of the movable mirror on the mask stage side is changed by measuring the rotation angle on both the wafer stage and the mask stage with a two-axis interferometer in the non-scanning direction in the embodiment of the present invention. FIG. 4 is an explanatory diagram showing a shape of a shot area and a shot arrangement in the case.

FIG. 8 is a plan view showing an example of a wafer mark used in the intra-shot multi-point EGA method.

FIG. 9 is an explanatory diagram of a method for measuring the amount of bending of the movable mirror 21X in the non-scanning direction on the reticle minute drive stage 11.

FIG. 10 is an explanatory view showing the shape of a shot area and the shot arrangement when the tilt of the movable mirror on the wafer stage side changes in the prior art.

[Explanation of symbols]

 4 Zθ axis drive stage 5 Wafer 6 Reference mark plate 7X, 7Y Moving mirror on wafer stage side 8 Projection optical system 11 Reticle micro drive stage 12 Reticle 13X1, 13X2, 13Y1, 13Y2 Interferometer main body 14X1, 14X2, 14Y1, 14Y2 Interferometer Main body 19, 20 Reticle alignment microscope 21X Moving mirror on reticle stage side 21Y1, 21Y2 Corner cube 22A Main control system 22D Reticle driving device

Claims (5)

[Claims] A mask stage for moving a mask on which a pattern for transfer is formed; and a substrate stage for moving a photosensitive substrate, wherein the mask is illuminated with illumination light for exposure. By scanning the mask in a direction corresponding to the predetermined direction through the mask stage in synchronization with scanning the substrate in a predetermined direction via the substrate stage, the pattern of the mask is formed on the substrate. In a scanning exposure apparatus for sequentially transferring, at least one axis of a substrate-side interferometer for measuring a position of the substrate stage in a scanning direction, and a position of the substrate stage in a non-scanning direction orthogonal to the scanning direction is set in the scanning direction. A biaxial substrate-side interferometer that measures at two points along the substrate stage, the substrate stage and the mask stage based on measurement values of the biaxial substrate-side interferometer for the non-scanning direction. And a rotation angle correcting means for correcting the relative rotation angle of the scanning exposure apparatus. 2. The scanning exposure apparatus according to claim 1, further comprising: a single-axis substrate-side interferometer for measuring the position of the substrate stage in the scanning direction at two positions along the non-scanning direction. The difference between the measurement value of the two-axis substrate-side interferometer for the non-scanning direction and the difference between the measurement values of the two-axis substrate-side interferometer for the scanning direction, A scanning exposure apparatus comprising a moving direction correcting means for correcting a moving direction. 3. A mask stage for moving a mask on which a pattern for transfer is formed, and a substrate stage for moving a photosensitive substrate, wherein the mask is illuminated with illumination light for exposure. By scanning the mask in a direction corresponding to the predetermined direction through the mask stage in synchronization with scanning the substrate in a predetermined direction via the substrate stage, the pattern of the mask is formed on the substrate. In a scanning exposure apparatus for sequentially transferring, a two-axis substrate-side interferometer that measures a position in a non-scanning direction orthogonal to a scanning direction of the substrate stage at two points along the scanning direction, and a scanning direction of the mask stage. A two-axis mask-side interferometer that measures a position in a non-scanning direction perpendicular to the mask stage at two points along the scanning direction of the mask stage; and a measurement value of the two-axis substrate-side interferometer, A scanning exposure apparatus comprising: a rotation angle correction unit configured to correct a relative rotation angle between the substrate stage and the mask stage based on a measurement value of the two-axis mask-side interferometer. 4. A mask stage for moving a mask on which a pattern for transfer is formed, and a substrate stage for moving a photosensitive substrate, wherein the mask is illuminated with illumination light for exposure. By scanning the mask in a direction corresponding to the predetermined direction through the mask stage in synchronization with scanning the substrate in a predetermined direction via the substrate stage, the pattern of the mask is formed on the substrate. In a scanning exposure apparatus that performs sequential transfer, a first biaxial axis for measuring a position in the scanning direction of one of the substrate stage and the mask stage at two locations along a non-scanning direction orthogonal to the scanning direction. An interferometer, a second two-axis interferometer that measures the position of the one stage in the non-scanning direction at two positions along the scanning direction of the stage, and the first two-axis interferometer The rotation angle of the one stage is detected based on the difference between the measurement values of the first and second stages. Based on the detection result and the difference between the measurement values of the second two-axis interferometer, the second
And a moving mirror bending amount calculating means for calculating a bending amount of the moving mirror for the two-axis interferometer. 5. The scanning exposure apparatus according to claim 1, wherein a position of the one of the substrate stage and the mask stage in a non-scanning direction orthogonal to a scanning direction is measured. A scanning type exposure apparatus further comprising a measuring unit for measuring a positional relationship between the mask and the substrate stage when a difference between the measured values of the two-axis interferometer exceeds a predetermined threshold value.