JP3920605B2 - Exposure equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure apparatus that forms a pattern on a surface of a glass substrate or a color filter, which is a substrate to be exposed, in a manufacturing process of a flat panel display such as a liquid crystal display or a plasma display. And a scanning type exposure apparatus that forms a pattern on the surface of the exposure target substrate.
[0002]
[Prior art]
Liquid crystal displays (LCDs) can be made thinner and lighter than CRTs (Cathode Ray Tubes), so they are used as display devices for CTV (Color Television) and OA equipment. The size of the 10-inch or larger has been increased, and further higher definition and colorization have been promoted.
[0003]
A liquid crystal display is produced by drawing a fine pattern on the surface of a glass substrate by photolithography. The exposure apparatus projects and transfers a fine pattern of a photomask onto a glass substrate. The exposure apparatus includes a projection system that projects a mask pattern onto a glass substrate using a lens or a mirror, and a proximity that transfers a mask pattern onto the glass substrate by providing a small gap between the photomask and the glass substrate. There is a method. Proximity type exposure equipment has inferior pattern resolution performance compared to the projection system, but the irradiation optical system is very simple, the throughput is high, and the cost performance from the viewpoint of the equipment cost is excellent. It is suitable for high volume production equipment.
[0004]
In the proximity type exposure apparatus, glass substrate positioning control, so-called proximity gap control, is performed so that the distance between the photomask and the glass substrate is set to a predetermined minute gap (separation gap). In proximity gap control, exposure blur or the like occurs when the gap is not set with high accuracy. Therefore, increasing the accuracy of the gap is an important factor for determining fine conditions during mask pattern transfer. Further, in the proximity type exposure apparatus, alignment control for superimposing a photomask and a glass substrate with high accuracy is performed. Normally, in the exposure process of transferring a mask pattern onto the glass substrate surface, a predetermined mask pattern is sequentially transferred to the glass substrate using a plurality of photomasks, so that the overlay accuracy between the photomask and the glass substrate by alignment control is high. It occupies an important position in the exposure performance.
[0005]
In recent years, the size of liquid crystal displays tends to become larger. As the size of the liquid crystal display is increased, the size of the glass substrate is increased, and accordingly, the size of the photomask is also increased. Therefore, as an exposure apparatus that transfers a mask pattern to a large glass substrate using a large photomask, the photomask and the glass substrate are held in a state where proximity gap control and alignment control are completed, and the photomask A scanning type exposure apparatus that exposes a mask pattern onto the surface of a glass substrate by scanning the glass substrate with exposure light has been adopted.
[0006]
FIG. 3 shows an example of a conventional scan type exposure apparatus. In FIG. 3A, the photomask M is attracted and held substantially horizontally by a mask holder 23 disposed on a moving base 21 via a plurality of support posts (four support posts in the illustrated example) 22a to 22d. Each column 22 a to 22 d is erected parallel to the upper surface of the moving base 21 and supports the four corners of the mask holder 23. On the other hand, the glass substrate P is attracted and held substantially horizontally on the exposure chuck 24 a of the alignment stage 24 provided on the moving base 21. The alignment stage 24 includes an exposure chuck 24a that holds the glass substrate P by suction, a Z-axis table 24b for proximity gap control, an XYθ table 24c for alignment, and the like. As shown in FIGS. 3A to 3C, the moving base 21 has a plurality of support blocks (see FIG. 3) on each of a pair of parallel guide rails 26a and 26b on the apparatus base 25 installed on the floor F. In the illustrated example, the guide rails 26a and 26b are mounted so as to be movable via three support blocks 27a to 27c and 27d to 27f.
[0007]
In the above scanning exposure apparatus, as shown in FIG. 3A, the movable base 21 is retracted from the irradiation position of the exposure light L, and the proxy between the photomask M and the glass substrate P is performed by the alignment stage 24 at the retracted position. Mitty gap control and alignment control are performed. That is, a predetermined proximity gap is set between the glass substrate P and the photomask M by raising the exposure chuck 24a by the Z-axis table 24b. Further, the glass substrate P and the photomask M are superimposed with high accuracy by positioning the exposure chuck 24a in the XYθ directions by the XYθ table 24c. After the proximity gap control and alignment control are completed, the moving base 21 is moved toward the irradiation position of the exposure light L by a predetermined drive mechanism (not shown) (moved in the direction of arrow Q), and a photomask By moving the M and the glass substrate P with respect to the exposure light L irradiated from a light source (not shown), the mask pattern of the photomask M is transferred onto the glass substrate surface at the irradiation position of the exposure light L. . When the transfer of the mask pattern to the glass substrate P is completed, the irradiation of the exposure light L by the light source is stopped, and the moving base 21 is moved from the transfer completion position of the mask pattern in the direction of arrow R by the driving mechanism to return to the retracted position. Further, even when the moving base 21 is moved in the R direction, if the exposure light L is irradiated, a double exposure amount can be obtained, so that the throughput can be improved.
[0008]
[Problems to be solved by the invention]
In the above scanning type exposure apparatus, since the large-sized photomask M and the glass substrate P are mounted on the moving base 21 in addition to the mask holder 23 and the alignment stage 24, the weight of the moving base 21 is as follows. Several tons. Therefore, during the movement of the moving base 21 is moved toward the irradiation position of the exposure light L, due to such sinking floor F, the guide rail 26a of the apparatus base 25, the 26b, for example, FIG. 3 In (a), waviness (or deflection) 26a'26b 'as indicated by the alternate long and short dash line occurs. The undulations 26a'26b 'are the largest in the two support blocks 27b and 27e arranged at substantially the center of the moving base 21 in the moving direction of the moving base 21, and 4 are arranged at both ends of the moving base 21. As the distance between the two support blocks 27a, 27c and 27d, 27f becomes closer, it gradually becomes smaller. As described above, when the swell 26a'26b 'is generated in each guide rail 26a, 26b, the support blocks 27a-27c, 27d-27f correspond to the swell amount of each guide rail 26a, 26b during the movement of the movement base 21. It is displaced by the specified amount. As a result, the moving base 21 receives the undulations of the guide rails 26a and 26b through the support blocks 27a to 27c and 27d to 27f, so that the surface states (flatness) on the support columns 22a to 22d vary. It will change according to the amount of displacement of support blocks 27a-27c and 27d-27f. As a result, the columns 22a to 22d are displaced, the support balance of the mask holder 23 by the columns 22a to 22d is lost, and the gap between the photomask M and the glass substrate P or the overlay is displaced. It was.
[0009]
Therefore, in order to solve the above-mentioned problem, a sensor is arranged above the mask holder, and the sensor detects the gap between the photomask and the glass substrate during the movement of the moving base and the amount of misalignment, and the detection result Based on this, it is conceivable to perform the exposure process while controlling the Z-axis table and the XYθ table. In this case, there arises a problem that the sensor disposed above the mask holder becomes a shadow of the exposure light and obstructs the exposure process. In order to prevent the pair of guide rails from swelling, it is conceivable to increase the surface accuracy of the guide rails with respect to each support block by increasing the rigidity of the device base. In this case, however, the weight of the device itself is increased. A further problem arises.
[0010]
The present invention has been made in view of the above points, and even if the guide swells during the movement of the movement base, a gap or overlay between the pattern forming mask and the substrate to be exposed occurs. It is an object of the present invention to provide an exposure apparatus in which no exposure is made.
[0011]
[Means for Solving the Problems]
An exposure apparatus according to the present invention is an exposure apparatus that performs exposure processing by scanning a mask for pattern formation and an exposure target substrate with respect to exposure light. A moving base for holding an exposure target substrate, forming a predetermined gap between the exposure target substrate and the mask, and mounting an alignment stage for aligning the exposure target substrate and the mask, and the mask And a pair of guides for guiding the moving base so as to scan the exposure target substrate with respect to exposure light, and the moving base with respect to one guide of the pair of guides at two positions on both ends. third support member for movably supporting the moving base at one position of the intermediate portion first and second support members for movably supporting, relative to the other guide, a total of three of the In which it equipped with a support member of the place. According to this, since the moving base is supported at two places with respect to one of the pair of guides and is supported at one place with respect to the other, the moving base is supported by the supporting members in a total of three places. Even if undulation occurs in the pair of guides during movement of the moving base, the moving base simply tilts by the amount of difference in the amount of undulation between one supporting member and the remaining two supporting members. The surface state (flatness) on the support column side does not change according to the undulations of the pair of guides (the surface is not distorted). As a result, distortion of each support column is prevented, so that the support balance of the mask holder by each support column is stabilized, and there is no occurrence of deviation in the gap or overlay between the mask and the exposure target substrate.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an exposure apparatus according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a schematic configuration of an exposure apparatus according to the present embodiment, (a) is a schematic configuration diagram of the exposure apparatus, and (b) is a moving base 3 and an apparatus base 4 of the exposure apparatus shown in (a). The figure which shows the arrangement | positioning aspect with the upper guide rails 6a-6c, (c) is the figure which shows the coupling | bonding aspect of the movement base 3 of the exposure apparatus shown by (a) and the guide rails 6a-6c on the apparatus base 4 It is.
The exposure apparatus according to the present embodiment is a scan type apparatus that performs an exposure process by scanning a photomask M and a glass substrate P with respect to the exposure light L, as shown in FIG. In FIG. 1, an exposure apparatus includes a mask holder 1, an alignment stage 2, a moving base 3 on which the mask holder 1, the alignment stage 2 and the like are mounted, and an apparatus base 4 on which the moving base 3 is movably mounted. And an arbitrary drive mechanism (not shown) for moving the moving base 3 with respect to the apparatus base 4 and a light source (not shown) for exposure light irradiation. The alignment stage 2 and the drive mechanism are driven and controlled by a control unit (not shown) configured by a microcomputer including an MPU, ROM, RAM, and the like. The mask holder 1 is formed in a frame shape having a space portion 1a for introducing exposure light at the center, and a plurality of columns (four in the illustrated example) 5a erected in parallel with the upper surface of the moving base 3. The four corners are supported by ~ 5d. The mask holder 1 sucks and holds the photomask M almost horizontally at the outer peripheral portion of the space 1a. The alignment stage 2 is disposed on the moving base 3 at a position facing the mask holder 1. The alignment stage 2 includes an exposure chuck 2a that holds the glass substrate P by suction, a Z-axis table 2b for proximity gap control, an XYθ table 2c for alignment control, and the like. The exposure chuck 2a sucks and holds the glass substrate P carried in from a substrate carry-in unit (not shown) almost horizontally. The moving base 3 is provided via three support blocks 7a to 7c formed so as to be in surface contact with a pair of guide rails 6a and 6b provided in parallel on the apparatus base 4 installed and fixed on the floor F. It is supported movably. That is, as shown in FIG. 1B, the moving base 3 is slidably supported on one guide rail 6a by one support block 7a provided substantially at the center in the longitudinal direction. Two support blocks 7b and 7c provided in the vicinity are slidably supported on the other guide rail 6b.
[0013]
In the exposure apparatus shown in this example, as shown in FIG. 1A, the moving base 3 is retracted from the irradiation position of the exposure light L, and the photomask M and the glass substrate P are moved by the alignment stage 2 at the retracted position. Pre-alignment control, proximity gap control, alignment control, and the like are performed. In the pre-alignment control, for example, the edge of the glass substrate P is detected in a non-contact manner using an edge detection sensor (not shown), and the carry-in deviation of the glass substrate P is determined by the control unit based on the detected position. Based on the above, the controller drives the XYθ table 2c in the XYθ direction to correct the carry-in deviation. In proximity gap control, for example, the gap amount between the photomask M and the glass substrate P is detected by four gap detection sensors (not shown), and the control unit controls the Z-axis table according to the gap amount. A predetermined proximity gap is set between the photomask M and the glass substrate P by driving 2b to raise the exposure chuck 2a. In the alignment control, for example, an alignment mark provided at a predetermined position of the photomask M and the glass substrate P is detected using a CCD or the like, and the amount of displacement of the alignment mark is obtained from the detection result. Based on this, the control unit drives the XYθ table 2c in the XYθ direction, thereby correcting the shift amount and overlaying the photomask M and the glass substrate P with high accuracy.
[0014]
After completion of the pre-alignment control, proximity gap control, alignment control, and the like as described above, the moving base 3 is moved toward the irradiation position of the exposure light L (moved in the direction of arrow P) by the drive mechanism. During the movement of the movement base 3, due to the sinking of the floor F or the like, the pair of guide rails 6a and 6b of the apparatus base 4 swells (or bends), that is, moves as indicated by a one-dot chain line, for example. Swells (or deflections) 6a ′ and 6b ′ that become maximum at the support block 7a at the center of the base 3 and gradually decrease as the two support blocks 7b and 7c at both ends of the moving base 3 become closer to each other occur. In this case, the support blocks 7a to 7c are displaced by an amount corresponding to the swell amount of the guide rails 6a and 6b. At this time, of the three support blocks 7a to 7c, one support block 7a slidably supports the moving base 3 on one guide rail 6a at its substantially center, and the remaining two support blocks 7b and 7c are Since the movable base 3 is slidably supported by the other guide rail 6b at both ends thereof, the displacement amount of one support block 7a that supports the movable base 3 at the center is the largest. The displacement amounts of the remaining two support blocks 7b and 7c that support the two at both ends are smaller than the displacement amount of the one support block 7a. Accordingly, during the movement, the movement base 3 is different in the displacement amount between the one support block 7a and the displacement amounts of the remaining two support blocks 7b and 7c, as indicated by a one-dot chain line in FIG. Since it is inclined toward the one sliding block 7a by an amount, the surface state (flatness) of the upper surface of the moving base 3 does not change according to the undulations 6a ′ and 6b ′ of the guide rails 6a and 6b. . This prevents displacement of the columns 5a to 5d, so that the support balance of the mask holder 1 by the columns 5a to 5d is stabilized, and a gap or overlap occurs between the photomask M and the glass substrate P. There is nothing wrong.
[0015]
The moving base 3 is moved further from the position indicated by the alternate long and short dash line toward the irradiation position of the exposure light L in FIG. As a result, the photomask M and the glass substrate P are scanned with respect to the exposure light L, and the exposure light L irradiates the photomask M from the space portion 1a of the mask holder 1 at the irradiation position. An exposure process for transferring the M mask pattern onto the glass substrate surface is performed. At this time, since there is no deviation in the gap or overlay between the photomask M and the glass substrate P, the mask pattern can be transferred onto the glass substrate surface with high accuracy. When the transfer of the mask pattern to the glass substrate P is completed, the irradiation of the exposure light L by the light source is stopped, and the moving base 3 is moved from the transfer completion position of the mask pattern in the direction of arrow R by the driving mechanism to return to the retracted position.
[0016]
In the exposure apparatus shown in the above-described embodiment, the movable base 3 is movably supported using the three sliding blocks 7a to 7c that are in surface contact with the guide rails 6a and 6b on the apparatus base 4, but will be described later. The moving base 3 may be movably supported on the guide rails 6a and 6b by using three support blocks 8a to 8c each having a steel ball. FIG. 2 shows an example of three support blocks 8a to 8c each having a steel ball. 2A is a schematic configuration diagram of a support block 8a that supports the moving base 3 on the guide rail 6a at substantially the center thereof, and FIG. 2B is a support that supports the moving base 3 on the guide rail 6b at one end thereof. (C) is a schematic block diagram of the support block 8c which supports the movement base 3 on the guide rail 6b at the other end.
[0017]
In each of FIGS. 2A, 2B, and 2C, the central view is a side sectional view of each of the support blocks 8a, 8b, and 8c, and the upper view is a holding member 8a1, 8b1 fixed to the lower surface of the moving base 3. 8c1 is a bottom view, and a lower view is a top view of holding members 8a2, 8b2, and 8c2 that slide on the guide rail 6a or 6b. In FIG. 2A, the support block 8a includes a steel ball holding member 8a1 fixed to the lower surface of the moving base 3, and a steel ball holding holder slidably disposed on the upper surface of the guide rail 6a. A member 8a2 and a steel ball 8a3 interposed between the holding members 8a1 and 8a2 are provided. The steel ball 8a3 is slidably accommodated in a substantially hemispherical recess 8a2 ' provided in the holding member 8a2 on the guide rail 6a side, and the upper surface of the spherical surface is a flat surface 8a1 of the holding member 8a1 on the moving base 3 side. Touch the 'and support it in a point contact state. 2B, the support block 8b includes a steel ball holding member 8b1 fixed to the lower surface of the moving base 3, and a steel ball holding holder slidably disposed on the upper surface of the guide rail 6b. A member 8b2 and a steel ball 8b3 interposed between the holding members 8b1 and 8b2 are provided. The steel ball 8b3 is slidably accommodated in a substantially hemispherical recess 8b2 ' provided in the holding member 8b2 on the guide rail 6b side, and the upper part of the spherical surface is a hemispherical shape of the holding member 8b1 on the moving base 3 side. It is accommodated and held in the conical recess 8b1 ′ . 2C, the support block 8c includes a steel ball holding member 8c1 fixed to the lower surface of the moving base 3, and a steel ball holding holder slidably disposed on the upper surface of the guide rail 6b. A member 8c2 and a steel ball 8c3 interposed between the holding members 8c1 and 8c2 are provided. The steel ball 8c3 is slidably accommodated in a substantially hemispherical recess 8c2 ′ provided in the holding member 8c2 on the guide rail 6b side, and the upper part of the spherical surface is provided in the holding member 8c1 on the moving base 3 side. It is housed and held in a substantially V-shaped groove 8c1 ′. The V-shaped groove 8c1 ′ extends in the longitudinal direction of the guide rail 6b. As a result, when undulations 6a 'and 6b' occur in the pair of guide rails 6a and 6b, the steel balls 8c3 are moved in the longitudinal direction of the guide rail 6b following the undulations 6a 'and 6b' of the respective guide rails 6a and 6b. It can move in the direction. That is, with the engagement portion between the recess 8b1 ′ of the support block 8b and the steel ball 8b3 as a fulcrum, the engagement portion between the groove 8c1 ′ of the support block 8c and the steel ball 8c3 is released in the guide longitudinal direction, and the support block 8a is flat. The contact portion between the surface 8a1 ′ and the steel ball 8a3 is allowed to escape in any direction such as the longitudinal direction of the guide or the lateral direction. Of course, the steel balls 8c1 to 8c3 are held by the holding members 8a2 to 8c2 on the guide rails 6a and 6b side so that the centers thereof are at the same height from the floor F. Note that the support blocks 8a to 8c shown in FIGS. 2A to 2C are not limited to the above support positions in the movement base 3, and may be appropriately applied to any support positions.
[0018]
As described above, if the moving base 3 is supported by the pair of guide rails 6a and 6b on the apparatus base 4 through the spherical surfaces by the steel balls 8a3 to 8c3 of the three support blocks 8a to 8c, the above-described case will be described. Since the contact area with respect to the guide rails 6a and 6b can be made smaller than in the case of the support blocks 7a to 7c, the displacement amount of the support blocks 8a to 8c due to the swells 6a ′ and 6b ′ of the guide rails 6a and 6b can be reduced. It can be further reduced. As a result, the amount of inclination of the moving base 3 due to the undulations 6a ′ and 6b ′ of the guide rails 6a and 6b is further reduced, and the support balance of the mask holder 1 by the columns 5a to 5d is further stabilized.
[0019]
【The invention's effect】
As described above, according to the exposure apparatus of the present invention, the moving base is supported by the pair of guides at the three different positions in the longitudinal direction of the guides by the support member. Even if waviness or the like occurs in the guide during movement, each support column is not displaced, so that the support balance of the mask holder by each support column is stabilized, so that the gap between the mask and the exposure target substrate is shifted or overlapped. It is possible to prevent the occurrence of the occurrence of an excellent effect.
[Brief description of the drawings]
FIG. 1 shows a schematic configuration of an embodiment of an exposure apparatus according to the present invention, (a) is a schematic configuration diagram of the exposure apparatus, and (b) is a movement base and guide rails of the exposure apparatus shown in (a). (C) is a view of the coupling state of the moving base and guide rail of the exposure apparatus shown in (a).
FIG. 2 is a schematic configuration diagram illustrating an example of a support block that supports a guide rail and a moving base by point contact.
FIG. 3 shows a schematic configuration of a conventional exposure apparatus, (a) is a schematic configuration diagram of the exposure apparatus, (b) is an arrangement pattern diagram of the movement base and guide rail of the exposure apparatus shown in (a), FIG. 7C is a view showing a coupling manner of the moving base and guide rail of the exposure apparatus shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mask holder 2 Alignment stage 3 Movement base 4 Apparatus base 5a-5d Support | pillar 6a, 6b Guide rail 7a-7c Support block 8a-8c Support block 8a3-8c3 Steel ball L Exposure light M Photomask P Glass substrate

Claims (3)

In an exposure apparatus that performs an exposure process by scanning a mask for pattern formation and a substrate to be exposed with respect to exposure light,
A mask holder that holds a mask via a plurality of support columns, and an exposure target substrate, holds a predetermined gap between the exposure target substrate and the mask, and aligns the exposure target substrate and the mask. A moving base on which an alignment stage is mounted;
A pair of guides for guiding the moving base so as to scan the mask and the exposure target substrate with respect to exposure light;
The first and second support members that support the movable base at two locations on both ends with respect to one guide of the pair of guides, and the movable base at one location in the middle with respect to the other guide An exposure apparatus comprising a total of three support members, a third support member that is movably supported by the first and second support members .   The exposure apparatus according to claim 1, wherein the support member at each location includes a block that moves in contact with the guide, and the block supports the moving base by surface contact. The support member at each location is provided at a predetermined position of the first holding member that moves in contact with the guide, the second holding member provided on the lower surface of the moving base, and the first holding member. A steel ball which is arranged so as to be able to roll in a substantially hemispherical or conical recess and is in contact with the second holding member at the upper part of the spherical surface to support the moving base. The second holding member of the first supporting member among the three supporting members is provided with a substantially hemispherical or conical recess for holding the steel ball , The second holding member of the support member is provided with a recess for holding the steel ball in a groove shape along the direction of the guide, and the second holding member of the third support member is flat. The exposure apparatus according to claim 1, wherein the exposure apparatus is in contact with the steel ball .

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