JPH0883744A - Scanning exposing device - Google Patents

Abstract

PURPOSE: To adjust the magnification and distortion against the scanning direction at a high speed of response with a simple mechanism. CONSTITUTION: A mask 3 is irradiated with light from a lighting optical system 1 and the image of the mask 3 is projected upon a plate 10 through a projecting optical system 5 which projects the unmagnified erect image of the mask 3 and a plane-parallel plate 8. The degree of shrinkage of a circuit pattern on the plate 10 in X-direction is measured with an alignment optical system 19A and the visual field 11 for exposure is moved by controlling the angle of rotation of the plane-parallel plate 8 in accordance with the measured results of the degree of shrinkage at the time of scanning the mask 3 and plate 10 in X- direction against the optical system 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning exposure apparatus such as a slit scan method or a step-and-scan method for sequentially exposing a mask pattern on a photosensitive substrate, and more particularly to a magnification or distortion in a scanning direction. The present invention relates to a scanning type exposure apparatus provided with the correction mechanism.

[0002]

2. Description of the Related Art For example, when manufacturing a semiconductor device or a liquid crystal display device, a mask (reticle, photomask, etc.) pattern is coated with a photoresist through a projection optical system (a glass plate, a semiconductor wafer, etc.). A) A projection exposure apparatus for projecting on is used. Conventionally, a projection exposure apparatus (stepper) has been widely used which collectively exposes a reticle pattern to each shot area on a plate by a step-and-repeat method. On the other hand, recently, in order to expose a large area pattern without imposing a burden on the projection optical system, the mask and plate are scanned in synchronization with the projection optical system to scan the pattern of the mask on the plate. A scanning type exposure apparatus that sequentially exposes a laser beam is attracting attention.

Even in such a scanning type exposure apparatus, when a new mask pattern is exposed by superposing it on the circuit pattern formed on the plate in the previous steps, it is necessary to superimpose both patterns with high precision. There is. To do this, when exposing the pattern to the first layer on the plate,
It is desirable that the projection magnification from the mask pattern to the plate be within a predetermined allowable range with respect to the design value on the entire surface of the plate. In the scanning type exposure apparatus, the magnification of the mask and the plate in the scanning direction is determined by the value of the relative scanning speed ratio between the mask and the plate, and the magnification in the non-scanning direction perpendicular to the scanning direction is the projection optical axis. It is determined by the projection magnification of the system itself. As a method of correcting the magnification in the scanning direction, for example, in Japanese Examined Patent Publication No. 5-29129, a linear air bearing is used as a bearing of a scanning stage, and the air pressure of the linear air bearing is partially A method of correcting the magnification due to the bending of the running surface of the scanning stage by controlling the above is disclosed.

Further, since recent semiconductor devices and the like are manufactured through complicated processing steps, even if a circuit pattern is exposed on a plate at an accurate magnification, the film etc. on the plate is partially removed in the subsequent processing steps. There is a case where the circuit pattern deviates from the designed size when the next mask pattern is exposed on the circuit pattern. In such a case, the magnification of the circuit pattern formed on the plate and a partial magnification error (that is, distortion) are measured, and the magnification and the distortion of the image of the mask pattern exposed on the plate are measured. It is necessary to adjust to the condition that was set. In this case, the adjustment of the magnification and the predetermined distortion in the non-scanning direction is performed by, for example, a method of adjusting the pressure of the gas in the closed space between the predetermined lenses in the projection optical system or a large number of lenses forming the projection optical system. It is carried out by a method of adjusting the position and inclination angle of a predetermined lens in the above.

As a method of adjusting the magnification and distortion in the scanning direction, for example, the above-mentioned Japanese Patent Publication No. 5-29 is used.
No. 129, there is a method of indirectly correcting magnification and distortion by providing a fine feed mechanism for finely moving the plate two-dimensionally and adjusting the position of the plate via the fine feed mechanism during scanning exposure. It is disclosed.

[0006]

Among the conventional techniques as described above, in the method of adjusting the position of the plate through, for example, the micro-feed mechanism, the micro-feed mechanism also increases as the mask and the plate increase in size. It is necessary to increase the size, but this has the disadvantage of increasing the manufacturing cost. Furthermore,
Since the minute feed mechanism has poor responsiveness, for example, when the circuit pattern on the plate partially expands or contracts in a narrow section in the scanning direction, it is not possible to accurately correct the distortion of only that part during scanning exposure. Have difficulty.

In the prior art, the method of partially controlling the air pressure of the linear air bearing to correct the distortion caused by the deflection of the running surface of the scanning stage can only roughly correct the distortion. Therefore, it is difficult to correct the partial distortion with high accuracy. Furthermore, in the recent scanning type exposure apparatus, instead of using one large projection optical system, a plurality of small partial projection optical systems are arranged in a plurality of rows at predetermined intervals along the scanning direction, and each partial projection optical system A method of exposing a mask pattern on a plate has been proposed.
This method has an advantage that a pattern of a larger area can be exposed simply by increasing the number of partial projection optical systems having a low manufacturing cost. When using a plurality of rows of partial projection optical systems arranged at a predetermined interval in the scanning direction in this way, in order to correct distortion that changes at short intervals along the scanning direction, at least the partial projection optical system of each row is used. It is necessary to adjust the exposure position in the scanning direction for each system. However, in the conventional method of using the minute feed mechanism and the method of correcting the deflection of the scanning surface of the scanning stage, the position of the plate can be uniformly adjusted in the scanning direction with respect to the entire plurality of partial projection optical systems. Therefore, it is difficult to correct partial distortion in a narrow range.

In view of the above problems, an object of the present invention is to provide a scanning type exposure apparatus which has a simple mechanism and is capable of adjusting magnification and distortion in the scanning direction at a high response speed. Further, the present invention is a scanning type exposure capable of easily and accurately adjusting the magnification and the distortion in the scanning direction on the entire surface of the plate when the exposure is performed by the scanning exposure method using a plurality of partial projection optical systems. The purpose is to provide a device.

[0009]

A scanning type exposure apparatus according to the present invention illuminates a mask (3) on which a transfer pattern is formed with exposure illumination light as shown in FIG. The image of the pattern is projected on the photosensitive substrate (10) through the projection optical system (5), and the mask (3)
By scanning the substrate (10) in a second direction (X direction) corresponding to the first direction in synchronization with the scanning of the substrate in the first direction (X direction). In a scanning type exposure apparatus for exposing on the substrate, an exposure field (11) of the pattern of the mask (3) on the substrate (10) by the projection optical system (5) is predetermined in the second direction (X direction). Optical member (8) that moves continuously within the range
It is provided with.

In this case, measuring means (19A) for measuring the amount of positional deviation between the position of the mask (3) in the first direction and the position of the substrate (10) in the second direction, and this measurement. Optical member control means (1) for controlling the amount of movement of the exposure field (11) by the optical member (8) according to the position of the substrate (10) in the second direction based on the measurement result of the means.
It is desirable to provide 2) and.

An example of the optical member is a rotation axis (9a) parallel to a direction orthogonal to the second direction (X direction).
It comprises a plane-parallel plate (8) rotatably provided around and a drive means (9) for rotating the plane-parallel plate. Further, as shown in FIG. 7, the projection optical system has a direction (Y) orthogonal to the second direction (X direction).
Direction), a plurality of partial projection optical systems (33A to 33D, 33E to 33G) arranged in a plurality of rows are supported for each of the plurality of partial projection optical systems or each row. Therefore, it is desirable to provide a plurality of the optical members (51, 52).

[0012]

According to the present invention, as shown in FIG. 2, for example, the expansion and contraction of the coating film on the substrate (10) causes the substrate (1
0) When the pattern (CP) formed on the substrate (10) is displaced in the scanning direction with respect to the image (11a) of the corresponding mask pattern, that is, a partial magnification error (distortion) in the pattern on the substrate (10). Is occurring,
An image (11) of the mask pattern is formed through the optical member (8).
The image formation position of a) is shifted on the pattern (CP),
Distortion is generated in the scanning direction. As a result, the overlay accuracy is maintained with high accuracy. on the other hand,
When the magnification in the scanning direction with respect to the image (11a) of the mask pattern of the pattern (CP) formed on the substrate (10) is changing, it is passed through the optical member (8) according to the scanning position. The exposure field (11) may be continuously changed in one direction.

In order to determine the amount of movement of the exposure visual field (11) by the optical member (8), for example, as shown in FIG. 3, alignment marks (26A ...
26J) is formed, and the alignment marks (27A to 27J) are exposed in parallel when the circuit pattern (10a) is also exposed on the substrate (10). Then, by scanning the mask (3) and the substrate (10) once before the exposure, the alignment marks (27A to 27J) with respect to the alignment marks (26A to 26J) are measured by using a measuring unit including, for example, the alignment optical system 19A. The positional deviation amount in the scanning direction is measured, and the measurement result is stored in the optical member control means (12). When performing scanning exposure after that,
The exposure visual field (11) may be sequentially moved through the optical member (8) by the stored positional deviation amount.

When the optical member is composed of the parallel flat plate (8) and the driving means (9), the parallel flat plate (8) is rotated (turned) by the driving means (9) clockwise or counterclockwise. The position of the exposure visual field (11) moves back and forth with respect to the scanning direction depending on the rotation angle. Next, as shown in FIG. 7, when the projection optical system includes a plurality of rows of partial projection optical systems (33A to 33D, 33E to 33G), for example, the exposure fields (36A to 36D) of the first row and 2
The distortion value may differ from the exposure field of view (36E to 36G) in the column. In such a case, the optical members (51, 52) may be arranged in each row, and the shift amount of the exposure visual field in the scanning direction (X direction) may be adjusted for each row. Further, when the distortion value in the exposure visual field is different for each partial projection optical system, an optical member for moving the exposure visual field may be provided for each partial projection optical system.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the scanning type exposure apparatus according to the present invention will be described below. In the present embodiment, the present invention is applied to a scanning type exposure apparatus that uses a single projection optical system of equal magnification. FIG. 1 shows a scanning type exposure apparatus of the present embodiment. In FIG. 1, illumination light I for exposure from an illumination optical system 1 is shown.
L passes through the dichroic mirror 2 and illuminates the arc-shaped illumination area 4 on the lower surface (pattern formation surface) of the mask 3 with a uniform illuminance distribution. The image of the pattern in the illumination area 4
A so-called Dyson type projection optical system 5 and a plane-parallel plate 8 as an optical member are used to project an image into an arc-shaped exposure field 11 on a plate 10.

The projection optical system 5 is a so-called Dyson type consisting of a lens 6 and a concave reflecting mirror 7, and is an objective optical system that projects an erect image at the same magnification. That is, the illumination light IL from the illumination area 4 is reflected by the inclined surface 6 a of the lens 6, then emitted from the convex surface 6 b of the lens 6, and travels toward the concave reflecting mirror 7.
The illumination light reflected by the concave reflecting mirror 7 is reflected by the lens 6
After being reflected by the sloped surface 6c through the convex surface 6b of the above, it goes toward the plane parallel plate 8. In the following, the Z axis is taken parallel to the optical axis AX on the plate 10 of the projection optical system 5, the X axis is parallel to the paper surface of FIG. 1, and the Y axis is perpendicular to the paper surface of FIG. 1 in a plane perpendicular to the Z axis. Take the axis. In this embodiment, the direction parallel to the X axis is the scanning direction of the mask 3 and the plate 10.

The plane-parallel plate 8 is made of a glass substrate and is rotated by a motor 9 in a θ direction about an axis 9a which is perpendicular to the optical axis AX and is parallel to the Y-axis which is also perpendicular to the scanning direction. Supported by. The motor 9 is, for example, a stepping motor, and rotates the plane-parallel plate 8 in either a clockwise direction or a counterclockwise direction according to a control signal from the main control system 12 and at an arbitrary angle with a predetermined resolution as a unit. After this, the plane-parallel plate 8 can be fixed in that state. Further, the motor 9 continuously changes the rotation angle of the plane-parallel plate 8 in either the clockwise direction or the counterclockwise direction in accordance with the position of the plate 10 in the X direction according to the control signal from the main control system 12. You can also let it. When the plane-parallel plate 8 rotates in this manner, the position of the exposure field 11 on the plate 10 moves in the X direction, which is the scanning direction, depending on the rotation angle. In this embodiment, the exposure field of view 11 is set during scanning exposure.
Is moved to correct a partial magnification error in the scanning direction, that is, distortion.

As described above, the projection optical system 5 of this embodiment is
The mask 3 and the plate 1 are used to project an erect image at the same magnification.
For 0, the projection optical system 5 may be scanned in the + X direction or the −X direction at the same scanning speed. Therefore, the carriage 13 is movably arranged on the device base 14 in the X direction, the mask 3 is placed on the upper plate 13b with the central portion of the carriage 13 cut out, and the plate 10 is placed on the bottom plate 13a. The drive motor 17 on the device base 14 drives the carriage 13 in the X direction (+ X direction or −X direction) with respect to the device base 14 via the feed screw 18. At this time, the projection optical system 5, the plane-parallel plate 8 and the motor 9 are attached to the device base 1
It is fixed to a frame (not shown) fixed to No. 4. Therefore, by driving the carriage 13 in the X direction, the mask 3 and the plate 10 are moved in the X direction with respect to the projection optical system 5 and the plane parallel plate 8.

A movable mirror 15 is fixed to one end of the bottom plate 13a of the carriage 13 in the X direction, and a laser beam for measurement is emitted from an external laser interferometer 16 to the movable mirror 15, and the carriage is driven by the laser interferometer 16. The X coordinate of 13 is constantly measured, and the measured X coordinate is supplied to the main control system 12. The main control system 12 controls the drive motor 17 based on the supplied X coordinate to control the position of the carriage 13 in the X direction and the moving speed in the X direction.

In this embodiment, a pair of alignment optical systems (only the front alignment optical system 19A in FIG. 1 is shown in the lateral direction of the dichroic mirror 2 above the mask 3 at predetermined intervals with respect to the paper surface of FIG. Has been placed). In the alignment optical system 19A, the alignment light AL emitted from the alignment light source 20
After being condensed by the condenser lens 21, passed through the beam splitter 22 and the first objective lens 23, is reflected by the dichroic mirror 2 and illuminates the alignment mark on the mask 3. As the alignment light, light having a weak sensitivity to the photoresist applied on the plate 10 is used, and as the light source 20, a halogen lamp or the like is used.

Alignment light A irradiated on the mask 3
A part of L is reflected by the alignment mark, and the remaining part of the L passes through the mask 3 and is then projected onto the alignment mark on the plate 10 through the projection optical system 5 and the plane-parallel plate 8. Then, the alignment light reflected by the alignment mark on the plate 10 returns to the mask 3 side through the plane-parallel plate 8 and the projection optical system 5 again, and the mask 3
The alignment light reflected by and the alignment light reflected by the plate 10 return to the beam splitter 22 via the dichroic mirror 2 and the first objective lens 23. Then, the alignment light reflected by the beam splitter 22 passes through the second objective lens 24 and forms an image of each alignment mark on the image pickup surface of the image pickup device 25 including a two-dimensional CCD or the like.

In this case, not only for the exposure illumination light IL but also for the alignment light AL, the arrangement surface of the mask 3 and the arrangement surface of the plate 10 are almost conjugate with respect to the projection optical system 5. In general, since the concave reflecting mirror has no chromatic aberration, the projection optical system 5 of this example also has the alignment light AL.
It is relatively easy to achromatize. The image pickup signal from the image pickup device 25 is supplied to the alignment processing system 26. Similarly, the image pickup signal from the alignment optical system paired with the alignment optical system 19A is also supplied to the alignment processing system 26.

FIG. 3A shows the arrangement of alignment marks on the mask 3. As shown in FIG. 3A, along the sides of the pattern region 3a of the mask 3 on the + Y direction side and the −Y direction side. Cross-shaped alignment marks 26A to 26E and 26F to 26J made of a light shielding film are formed at a predetermined pitch in the X direction in the light transmitting portion. In this case, the observation area F set at the end of the arcuate illumination area 4 in the -Y direction.
A is an observation area by the alignment optical system 19A in FIG. 1, and an observation area FB set at the end of the illumination area 4 in the + Y direction is an observation area by another alignment optical system.

FIG. 3B shows the arrangement of alignment marks on the plate 10. As shown in FIG. 3B, the sides of the shot area 10a of the plate 10 on the + Y direction side and the −Y direction side. Along the line, cross-shaped alignment marks 27A to 27 made of a reflective film at a predetermined pitch in the X direction.
E and 27F to 27J are formed. These alignment marks 27A to 27J were formed at the same time when the circuit pattern was formed in the shot area 10a in the steps up to that point. In addition, the alignment mark 27
The designed sequence of A to 27J is the alignment mark 26
It is the same as the sequence of A to 26J. However, in reality, the shape of the circuit pattern on the shot area 10a and the arrangement of the alignment marks 27A to 27J deviate from the designed values due to the expansion and contraction of the film on the plate 10. In this embodiment, the total or partial expansion / contraction amount of the circuit pattern on the shot area 10a is estimated from the displacement of the alignment marks 27A to 27J.

Specifically, for example, when measuring the positional deviation amount of the alignment marks 27C and 27H on the plate 10 with respect to the alignment marks 26C and 26H on the mask 3, as shown in FIG. Alignment mark 26C and alignment mark 27C inside
In the state where the image 27CM of the image is stored, the image in the observation area FB is taken by the corresponding alignment optical system, and the obtained image pickup signal is processed by the alignment processing system 26 of FIG. A displacement amount ΔX2 in the X direction and a displacement amount ΔY2 in the Y direction are obtained. Similarly, as shown in FIG. 4B, the alignment mark 26H in the observation area FA and the image 27HM of the alignment mark 27H are set to the alignment optical system 19A.
The alignment mark image 2 is obtained by processing the obtained image pickup signal by the alignment processing system 26.
A displacement amount ΔX1 of 7HM in the X direction and a displacement amount ΔY1 of the YHM in the Y direction are obtained.

Next, an example of the scanning exposure operation of this embodiment will be described. First, the expansion / contraction amount of the circuit pattern formed in the shot area 10a on the plate 10 is obtained as follows. That is, by moving the carriage 13 in the −X direction while the illumination light IL is shielded and the alignment light AL is emitted in FIG.
In the observation areas FA and FB of the two alignment optical systems, the alignment marks 2 on the mask 3 are
Position 6F and 26A. At this time, the observation area FA
And FB also accommodate the images of the alignment marks 27F and 27A on the plate 10, respectively. In this state, the alignment optical system 19A and the alignment processing system 2 of FIG.
6, the positional deviation amount of the alignment mark 27F in the X direction and the Y direction of the image through the projection optical system 5 is measured with the alignment mark 26F as a reference. In parallel with this, another alignment optical system measures the amount of misalignment of the alignment mark 27A in the X and Y directions with the other alignment mark 26A as a reference, and the two sets of misalignment amounts are sent to the main control system 12. Supply.

Next, the carriage 13 in FIG. 1 is moved in the + X direction to set the alignment marks 26G and 26B in the observation areas FA and FB, respectively, and then the alignment marks 27G and 26B with reference to the alignment marks 26G and 26B. The amount of positional deviation of the image of 27B is measured and supplied to the main control system 12. Similarly, alignment mark 2
6C, 26H to 26E, and 26J are used as a reference, and the positional deviation amount of the images of the alignment marks 27C, 27H to 27E, and 27J is measured and supplied to the main control system 12.

The main control system 12 calculates the expansion / contraction amount of each portion of the circuit pattern in the shot area 10a from the positional displacement amount of the images of the alignment marks 27A to 27J on the plate 10. After that, the carriage 13 in FIG. 1 is further moved in the + X direction to move the illumination area 4 in FIG. 3A to the outside of the pattern area 3a. Then, while the irradiation of the illumination light IL is started, the carriage 13 is accelerated in the −X direction so that the scanning speed of the carriage 13 reaches a constant speed when the illumination area 4 reaches the pattern area 3a, and scanning is performed. Exposure is performed by the exposure method. During this scanning exposure, the magnification and distortion of the projected image of the mask 3 are corrected as follows.

First, when the shot area 10a extends in the non-scanning direction (Y direction) perpendicular to the scanning direction with, for example, the magnification β (β> 1), for example, each optical member constituting the projection optical system 5 is formed. The scanning exposure is performed in a state where the magnification (design value is 1) of the projected image of the pattern of the mask 3 is adjusted to β by adjusting the position of. This means to correct the magnification of the projected image by the projection optical system 5.

When the expansion / contraction ratio of the shot area 10a is isotropic and the circuit pattern in the shot area 10a is uniformly expanded in the scanning direction (X direction) by the magnification β, The value of the ratio of the scanning speed of the plate 10 in the −X direction to the scanning speed of the mask 3 in the −X direction during scanning exposure must be β. However, in this embodiment, since the mask 3 and the plate 10 are scanned by the integrated carriage 13, the carriage 13 moves in the -X direction during scanning exposure in order to set the value of the ratio of the scanning speeds of both to β. Accordingly, the main control system 12 of FIG. 1 gradually rotates the plane-parallel plate 8 counterclockwise via the motor 9. As a result, the exposure field 11 gradually shifts in the + X direction, so that the plate 10 is substantially β (>) in the −X direction with respect to the mask 3.
This is equivalent to scanning at the speed ratio of 1). As a result, the pattern of the mask 3 can be exposed to the circuit pattern on the shot area 10a with high overlay accuracy.

Referring to FIG. 2, the plane-parallel plate 8 in that case.
Find the angular velocity of. In FIG. 2, assuming that the thickness of the plane-parallel plate 8 is d and the refractive index is n, the plane-parallel plate 8 is formed into a plate 10.
When it is rotated clockwise from the state parallel to
The position shift Δ in the −X direction of the illumination light IL vertically incident on the plate 10 can be expressed as follows. Δ≈ (1-1 / n) d · φ (1) For example, the thickness d of the plane-parallel plate 8 is 1 mm and the refractive index n is 1.5. If the circuit pattern having a length of 100 mm in the scanning direction extends on the plate 10 by 10 μm, the position shift Δ may be set to 10 μm (0.01 mm) when the mask 3 is scanned by 100 mm. . That is, according to the following equation, the angle φ at that time is about 0.
It will be 03 rad.

0.01 ≈ (1-1 / 1.5) · 1 · φ (2) φ ≈ 0.03 [rad] (3) In this case, the scanning speed of the carriage 13 is fixed at 100 m.
If m / s, the angular velocity w of the plane-parallel plate 8 is 0.03.
It becomes rad / s. When the carriage 13 is scanned in the −X direction, the angle φ has a negative value in FIG. 2 and the plane-parallel plate 8 is rotated counterclockwise at the angular velocity w.

Next, when the expansion / contraction ratio of the shot area 10a is anisotropic, and the expansion / contraction ratio in the scanning direction (X direction) of each portion changes, during scanning exposure. As the carriage 13 moves in the + X direction, the main control system 12 in FIG. 1 changes the rotation angle of the plane parallel plate 8 in the θ direction via the motor 9. Specifically, during the scanning exposure,
As shown in FIG. 2, the position of the circuit pattern CP already formed on the plate 10 is originally the circuit pattern CP.
From the projection position of the mask pattern 11a projected on the −
If it is deviated in the X direction, the mask pattern 11
The rotation angle of the plane-parallel plate 8 may be controlled so that the position of a overlaps the circuit pattern CP. In this case, the displacement amount of the circuit pattern CP in the scanning direction is calculated by interpolating the displacement amount of the alignment marks 27A to 27J. As a result, the distortion of the projected image of the mask pattern in the scanning direction is corrected according to the circuit pattern on the plate 10.

Although the plane-parallel plate 8 is arranged on the plate 10 in FIG. 1, the plane-parallel plate 8 may be arranged directly below the mask 3, for example. Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment uses a pair of curved plates instead of the plane-parallel plate 8 of the first embodiment, and in FIGS.
The same reference numerals are given to the portions corresponding to, and the detailed description thereof will be omitted.

FIG. 5 shows the scanning type exposure apparatus of this embodiment.
In FIG. 5, between the projection optical system 5 and the plate 10, a pair of cylindrical curved plates 28 and 29 made of glass and curved in a cylindrical shape along the optical axis AX of the projection optical system 5 face each other with convex surfaces. Are arranged as follows. The curved plates 28 and 29 are
Each of the curved plates 28 and 29 is formed of a part of a cylinder having the same thickness and the same outer surface with the same radius of curvature, and the symmetry axes of the outer cylindrical surfaces of the curved plates 28 and 29 are orthogonal to the scanning direction (X direction) in the Y direction (FIG. 5).
Direction perpendicular to the plane of the paper). That is, the curved plate 28
And 29 the generatrix of the cylindrical outer surface is parallel to the Y direction.
Further, the curved plate 28 on the projection optical system 5 side is supported so as to be driven by a desired amount in the + X direction or the −X direction along a guide 30 arranged in parallel with the X direction. The other structure is similar to that of the first embodiment shown in FIG.

In this embodiment, since the curved plates 28 and 29 have the same cylindrical surfaces arranged in opposite directions, the mask 3
The magnification of the projected image from the plate 10 to the plate 10 is the same as the case where the curved plates 28 and 29 are not provided. In this state, as shown in FIG. 6, when the curved plate 28 is moved in the + X direction, the illumination light IL that is vertically incident on the plate 10 moves in the −X direction as shown by the dotted line. That is, the curved plate 28
By moving in the same direction, the exposure field 11 can be moved in the opposite direction.

During the scanning exposure in this embodiment, the mask 3 and the plate 10 scan in the + X direction or the -X direction at a predetermined scanning speed relative to the projection optical system 5 and the pair of curved plates 28 and 29. To be done. Then, the movement amount of the bending plate 28 in the X direction is continuously controlled according to the expansion / contraction amount of the circuit pattern in the shot area on the plate 10 and the distribution of the expansion / contraction amount, according to the position of the plate 10 in the X direction. To be done. As a result, the position of the exposure field 11 is adjusted in the scanning direction, the magnification of the projected image of the mask pattern in the scanning direction and the distortion are corrected, and the circuit pattern on the plate 10 and the projected image of the mask pattern are superimposed. The accuracy is kept high.

Now, referring to FIG. 6, the relationship between the amount of movement of the bending plate 28 in the X direction and the amount of shift of the exposure field 11 in the X direction will be determined. Therefore, when the radius of curvature of the inner surface of the bending member 28 is Ra, the thickness is d, and the refractive index is n, −X from the center of curvature of the position where the illumination light IL enters the bending member 28.
The distance in the direction is δa. In this case, if the radius of curvature Ra is sufficiently larger than the interval δa, the gradient of the bending member 28 at the incident position of the illumination light IL, that is, the incident angle of the illumination light IL is approximately δa / Ra. Therefore, the bending member 28
Of the positional deviation Δ of the illumination light IL in the −X direction after passing through
a becomes as follows.

Δa≈d (1-1 / n) · δa / Ra (4) Further, the radius of curvature of the bending member 29 is Rb (= −Ra), the thickness is d, and the refractive index is n. Letting δb be the displacement amount in the −X direction from the center of curvature of the position of the illumination light IL that is incident on (Δb = δa in the initial state), the displacement of the illumination light IL in the −X direction by the bending member 29. Amount Δ
b is as follows.

Δb≈d (1-1 / n) · δb / Rb (5) In this case, in the initial state, Rb = −Ra and δb = δ
Since a is satisfied, the lateral shift amount of the illumination light IL in the X direction by the bending members 28 and 29 is zero. Next, when only the bending member 28 is moved in the + X direction by α, the illumination light IL
The shift amount Δa ′ in the −X direction by the bending member 28 of
It looks like this:

Δa′≈d (1-1 / n) · (δa + α) / Ra (6) On the other hand, the shift amount Δb ′ of the illumination light IL in the −X direction by the bending member 29 is the same as that of the equation (5). Is. Therefore,
From equations (5) and (6), the shift amount Δ of the illumination light IL in the −X direction by the bending members 28 and 29 is as follows. However, Rb = −Ra and δb = δa.

Δ = Δa ′ + Δb′≈d (1-1 / n) (δa + α−δb) / Ra = d (1-1 / n) · α / Ra (7) That is, the bending member 28 is moved in the scanning direction. If it is moved by α, the illumination light will be shifted in the direction opposite to the moving direction in proportion to the moving amount α. Now, assuming that the refractive index n is 1.5, the thickness d is 6 mm, and the radius of curvature Ra is 200 mm, the circuit pattern on the plate 10 is 10 μm (0.01 mm) per 100 mm in the scanning direction as in the first embodiment. Suppose that it is stretched. In this case, when the scanning speed of the plate 10 in the + X direction is 100 mm / s, when the bending member 28 is moved in the + X direction by α for 1 second,
It suffices that the shift amount Δ in the −X direction of the expression (7) becomes 0.01 mm. That is, α is approximately as follows.

Α = Δ · Ra / {d (1-1 / n)} = 0.01 · 200 / {(1/3) · 6} = 1 [mm] (8) Therefore, the scanning speed is 100 mm / If s, the bending member 28 may be moved in the + X direction at 1 mm / s. Instead of moving the bending member 28, the bending member 29 may be moved, or both the bending members 28 and 29 may be moved in opposite directions.

Next, a third embodiment of the present invention will be described with reference to FIGS. 7 and 8. In the present embodiment, the present invention is applied to a scanning type exposure apparatus having a projection optical system including a plurality of partial projection optical systems that respectively project erect images of equal magnification. FIG. 7 shows the scanning type exposure apparatus of the present embodiment. In FIG. 7, the illumination light from the illumination optical system 31 (for example, g-line (wavelength 435 nm) or i-line (wavelength 365n) is used.
m) and the like) are seven trapezoidal visual field regions 32A to 32, which will be described later, arranged in two rows on the mask 3 in the scanning direction (X direction).
A rectangular area surrounding each G is uniformly illuminated. The trapezoidal visual field regions 32A to 32G are selected as shapes as similar as possible to the shape of the maximum visual field region of the partial projection optical system described later. In addition, each visual field region 32A to 32G
Are areas defined by the field stop in the partial projection optical system. Therefore, the illumination optical system 31 may illuminate one large rectangular illumination area including all of the visual field areas 32A to 32G with exposure light.

In FIG. 7, below the mask 3, seven partial projection optical systems 33A to 33G are arranged in two rows, and the patterns of the visual field regions 32A to 32G on the mask 3 are respectively formed. It is projected on the trapezoidal exposure fields 36A to 36G on the plate 10 via 33A to 33G. Hereinafter, with reference to FIG. 8, the partial projection optical system 33A to
33G will be described. The partial projection optical system 33A
33G have the same configuration as each other, only the partial projection optical system 33A will be described.

FIG. 8 is a lens configuration diagram of the partial projection optical system 33A. This partial projection optical system 33A is a combination of two sets of optical systems obtained by modifying the Dyson type optical system. In FIG. 8, the partial projection optical system 33A is
It comprises a first partial optical system 34Aa, 45, 46, 34Ab, a field stop 49, a common plane parallel plate 51, and a second partial optical system 35Aa, 47, 48, 35Ab. Each of the second partial optical systems is a modification of the Dyson type optical system.

The first partial optical system includes a right-angle prism 34Aa having a reflecting surface arranged at an inclination angle of 45 ° with respect to the lower surface (pattern forming surface) of the mask 3 and light parallel to the lower surface of the mask 3. 34A having a right-angled prism with an axis and a flat surface
and the plano-convex lens component 45 cemented to a, and one surface having a meniscus shape as a whole is cemented to the convex surface (bonding surface 45a) of the plano-convex lens component 45 and the other surface (plano-convex lens component 45).
Lens component 46 in which the concave surface is a reflection surface 46a.
And a right-angle prism 34Ab having a reflection surface which is orthogonal to the reflection surface of the right-angle prism 34Aa and is arranged at an inclination angle of 45 ° with respect to the lower surface of the mask 3. Right angle prism 3
4Ab is also joined to the plane portion of the plano-convex lens component 45, and the glass material of the plano-convex lens component 45 and the glass material of the lens component 46 are different.

The light path from the illumination area including the visual field area 32A on the mask 3 is deflected by 90 ° by the right-angle prism 34Aa and enters the plano-convex lens component 45. The light from the right-angle prism 34Aa is refracted at the cementing surface 45a between the plano-convex lens component 45 and the lens component 46, enters the lens component 46, and reaches the reflecting surface 46a on which the reflecting film is vapor-deposited. The light reflected by the reflecting surface 46a is refracted again by the cementing surface 45a, passes through the plano-convex lens component 45, and reaches the right-angle prism 34Ab. The light from the plano-convex lens component 45 has its optical path deflected by 90 ° by the reflecting surface of the right-angle prism 34Ab, and forms a primary image of the mask 3 on the exit surface side of the right-angle prism 34Ab. Here, in the primary image of the mask 3 formed by the first partial optical systems 34Aa to 34Ab, the lateral magnification in the X direction (the optical axis direction of each partial optical system) is positive, and the lateral magnification in the Y direction is negative. It is a normal size image.

The light from the primary image passes through the parallel plane plate 51 and the second partial optical system 35Aa, 47, 48, 35Ab to expose the secondary image of the mask 3 on the plate 10 in the exposure field 36.
Form A. Since the configurations of the second partial optical systems 35Aa to 35Ab are the same as those of the first partial optical systems 34Aa to 34Ab, the description thereof will be omitted. That is, the second partial optical system 35Aa-
Like the first partial optical systems 34Aa to 34Ab, the 35Ab forms a lateral magnification unity-magnification image that is positive in the X direction and negative in the Y direction. Therefore, the secondary image formed on the plate 10 is an erect image of the mask 3 at an equal magnification (an image in which the lateral magnification in the vertical and horizontal directions is positive). The partial projection optical system 33A including the first and second partial optical systems is a double-sided telecentric optical system.

The above-mentioned first and second partial optical systems are constructed so that their respective reflecting surfaces 46a and 48a are oriented in the same direction. This makes it possible to reduce the size of the entire projection optical system. Further, the first and second partial optical systems include an optical path between the plano-convex lens component 45 and the reflecting surface 46a,
The optical path between the plano-convex lens component 47 and the reflecting surface 48a is filled with a glass material. Thereby, the plano-convex lens components 45 and 47 and the reflecting surfaces 46a and 48a
There is an advantage that eccentricity does not occur.

As the first and second partial optical systems,
Plano-convex lens components 45, 47 and corresponding reflecting surfaces 46a, 4
A so-called Dyson type optical system itself, in which the space between 8a and 8a is air, may be used. This Dyson type optical system is described in detail in J.Opt.Soc.Am.vol.49,713-716 (1959). In FIG. 8, in the present embodiment, the field stop 49 is arranged at the position of the primary image formed by the first partial optical system. The field stop 49 has a trapezoidal opening, and the area on the mask 3 that is conjugate with the opening of the field stop 49 is the field area 32A. Further, the exposure field 36A having a trapezoidal shape is a region on the plate 10 which is conjugate with the opening of the field stop 49.
Thus, the pattern in the visual field region 32A is exposed in the exposure visual field 36A.

Further, by rotating the plane parallel plate 51 about an axis parallel to the Y direction orthogonal to the scanning direction, the exposure field 36A can be shifted in the + X direction or the -X direction. Since the plane-parallel plate 51 of this embodiment is common to the partial projection optical systems 33A to 33D in the first row as shown in FIG. 7, it is arranged at a predetermined pitch in the Y direction by the partial projection optical system in the first row. The exposed exposure fields 36A to 36D are shifted in parallel in the + X direction or the −X direction by the same amount.

Returning to FIG. 7, the projection optical system 33E ...
The exposure fields 36E to 36G of 33G are arranged at positions different from the exposure fields 36A to 36D in the X direction and so as to fill the space between the exposure fields 36A to 36D in the Y direction. Then, a common plane parallel plate 52 is arranged in the vicinity of the image forming plane of each primary image by the projection optical systems 33E to 33G, and the plane parallel plate 52 is rotated about an axis parallel to the Y direction to expose the exposure field. 36A to 36D can be displaced in parallel in the + X direction or the -X direction by the same amount.

Here, the mask 3 is placed on a mask stage (not shown), and the plate 10 is mounted on the plate stage 3.
It is mounted on 7. Here, the mask stage and the plate stage 37 move in synchronization with the X direction in FIG. As a result, the illumination optical system 31 is provided on the plate 10.
The images of the mask 3 illuminated by are sequentially transferred, and exposure by a so-called scanning exposure method is performed. When the scanning of the entire surface of the mask 3 by the visual field regions 32A to 32G is completed by the movement of the mask 3, the image of the mask 3 is transferred onto the entire surface of the plate 10. That is, the mask pattern is exposed on the entire surface of the plate 10 by joining the images in the exposure fields 36A to 36D and the images in the adjacent exposure fields 36E to 36G in the Y direction.

A reflecting member 38 having a reflecting surface along the Y axis and a reflecting member 39 having a reflecting surface along the X axis are provided on the plate stage 37. On the exposure apparatus main body side, an interferometer such as He-Ne (6
A laser light source 40 for supplying a laser light such as 33 nm), a beam splitter 41 for splitting the laser light from the laser light source 40 into a laser light for X-direction measurement and a laser light for Y-direction measurement, and a laser from the beam splitter 41 A prism 42 for projecting light onto the reflecting member 38, and prisms 43, 44 for projecting laser light from the beam splitter 41 onto two points on the reflecting member 39 are provided. Thereby, the position of the plate stage 37 in the X direction, the position in the Y direction, and the rotation angle in the XY plane can be detected. Note that, in FIG. 7, a detection system for detecting after the laser light reflected by the reflecting members 38 and 39 and the reference laser light are interfered with each other is not shown.

Also in this embodiment, the amount of expansion and contraction of the circuit pattern on the plate 10 with respect to the mask 3 is measured in advance by an alignment optical system (not shown), and during scanning exposure, it is determined according to the position of the plate stage 37 in the X direction. By independently adjusting the rotation angles of the plane-parallel plates 51 and 52, the magnification and distortion of the projected image of the mask pattern are matched with the circuit pattern on the plate 10. At this time, since it can be considered that the expansion and contraction amounts of the circuit patterns in the scanning direction are substantially the same in the exposure field of view of each row, the common plane parallel plates 51 and 52 are used in each row. Therefore, there is an advantage that the control mechanism is simple.

The plane-parallel plates 51 and 52 may be arranged, for example, directly above the plate 10 or directly below the mask 3. Further, when the expansion / contraction amount of the circuit pattern can be individually measured in the area subdivided in the Y direction on the plate 10, each of the partial projection optical systems 33A to 33G has a parallel plane for independently correcting the exposure field. A face plate is provided and the exposure field of view 36
The positions of A to 36G in the scanning direction may be controlled independently of each other.

Instead of the plane-parallel plate, the second plate shown in FIG.
The exposure field may be shifted by using the curved members 28 and 29 used in the embodiment. In the third embodiment described above, a modified optical system of a Dyson type optical system having a plano-convex lens component and a concave mirror is used as a partial projection optical system for obtaining an erecting normal image of equal magnification as shown in FIG. However, as a partial projection optical system for obtaining an erect normal image at the same magnification, for example, a concave mirror,
It is also possible to use an Offner type optical system in which a convex mirror and a concave mirror are arranged in order. Furthermore, a projection optical system using only a lens composed of a refracting system may be used.

Further, although the projection optical system for projecting an erect image at the same magnification is used in the above embodiment, the present invention is also applied to the case where a projection optical system for projecting an inverted image at a reduction magnification is used. It goes without saying that you can do it. For example, when a projection optical system that projects an inverted image is used, the mask and the plate are scanned in the opposite direction. As described above, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0060]

According to the present invention, by moving the exposure field of the mask pattern in the second direction (scanning direction) on the substrate by the optical member, the magnification and distortion of the projected image of the mask pattern can be easily adjusted. In addition, there is an advantage that it can be adjusted at a high response speed. Further, when measuring the amount of positional deviation between the mask and the substrate in the scanning direction by the measuring means and controlling the amount of movement of the exposure visual field by the optical member via the optical member control means based on this measurement result, By moving the exposure visual field in accordance with the measured positional deviation amount, the mask pattern can be superimposed on the pattern on the substrate with high accuracy.

Further, when the optical member is composed of the plane-parallel plate and the driving means, the amount of movement of the exposure field can be controlled only by controlling the rotation angle of the plane-parallel plate. Next, when the projection optical system is composed of a plurality of partial projection optical systems arranged in a plurality of rows (for example, in a zigzag pattern), when an optical member is provided for each row, By simply moving the exposure field in the scanning direction with an optical member in common, the projected images of each row can be accurately stitched together, and the entire surface of the substrate (plate) can be easily and accurately shared in the non-scanning direction. Moreover, there is an advantage that the magnification and distortion of the mask pattern in the scanning direction can be corrected.

Further, when each of the plurality of partial projection optical systems is provided with an optical member for independently moving the exposure field in the scanning direction, when the expansion / contraction ratio changes in the non-scanning direction on the substrate. However, there is an advantage that the magnification and distortion of the mask pattern in the scanning direction can be corrected on the entire surface of the substrate according to the expansion / contraction ratio of the substrate.

[Brief description of drawings]

FIG. 1 is a configuration diagram including a partial cross-sectional view showing a first embodiment of a scanning exposure apparatus according to the present invention.

FIG. 2 is a diagram showing a relationship between a rotation angle of a plane-parallel plate 8 in FIG. 1 and a displacement amount of a projected image.

3A is a plan view showing the arrangement of alignment marks on the mask 3 of FIG. 1, and FIG. 3B is a plan view showing the arrangement of alignment marks on the plate 10 of FIG.

FIG. 4 is an enlarged view showing an observation image by the alignment optical system of FIG.

FIG. 5 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 6 is an enlarged view showing the relationship between the positional shift amount of the bending member and the lateral shift amount of the projected image in FIG.

FIG. 7 is a schematic configuration diagram showing a third embodiment of the present invention.

8 is an enlarged side view showing the configuration of a partial projection optical system 33A in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 illumination optical system 3 mask 5 projection optical system 8 parallel plane plate 9 motor 10 plate 12 main control system 19A alignment optical system 20 light source for alignment 23 first objective lens 24 second objective lens 25 imaging device 26A to 26J on a mask Alignment mark 27A to 27J Alignment mark on plate 28,29 Curved member 51,52 Parallel plane plate

Claims (4)

[Claims] 1. A mask in which a pattern for transfer is formed is illuminated with illumination light for exposure, and an image of the pattern of the mask is projected onto a photosensitive substrate through a projection optical system,
A scanning type in which a pattern of the mask is sequentially exposed on the substrate by scanning the substrate in a second direction corresponding to the first direction in synchronization with the scanning of the mask in the first direction. An exposure apparatus, comprising: an optical member for continuously moving an exposure field of the pattern of the mask on the substrate by the projection optical system in the second direction within a predetermined range. apparatus. 2. A measuring means for measuring a positional deviation amount between a position of the mask in the first direction and a position of the substrate in the second direction, and based on a measurement result of the measuring means, The second of the substrate
2. The scanning type exposure apparatus according to claim 1, further comprising optical member control means for controlling the amount of movement of the exposure visual field by the optical member according to the position in the direction. 3. The optical member comprises a plane-parallel plate rotatably provided around a rotation axis parallel to a direction orthogonal to the second direction, and a drive means for rotating the plane-parallel plate. The scanning exposure apparatus according to claim 1 or 2, characterized in that. 4. The projection optical system comprises a plurality of partial projection optical systems arranged in a plurality of rows along a direction orthogonal to the second direction, each of the plurality of partial projection optical systems. 4. The scanning type exposure apparatus according to claim 1, wherein a plurality of the optical members are provided so as to correspond to each row.