JP4313528B2 - Exposure equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure apparatus for transferring and forming a circuit pattern of a photomask on a surface of a workpiece to be exposed such as a glass substrate in the manufacture of a display panel used for a liquid crystal display (LCD), a plasma display, etc. In particular, the present invention relates to a photomask that can be appropriately sucked and held by a mask holder with a simple configuration.
[0002]
[Prior art]
A liquid crystal display (LCD) is widely used as a display device for color televisions, office automation equipment, and the like because the thickness and weight of the liquid crystal display (LCD) can be reduced as compared with a conventional CRT (Cathode Ray Tube) display. Recently, the vertical and horizontal sizes of liquid crystal displays have been increasing.
[0003]
For example, a substrate exposure apparatus used for manufacturing a liquid crystal display panel projects and transfers a fine circuit pattern of a photomask onto a glass substrate, and is roughly divided into a projection system and a proximity system. There is a thing by. The projection method is a method in which a mask pattern is projected onto a glass substrate through a lens or a mirror, and the proximity method is a method in which a minute proximity gap is provided between the photomask and the glass substrate, and the mask pattern is made of glass. This is a method of transferring onto a substrate. Proximity-type substrate exposure equipment has lower resolution performance than projection-type substrate exposure equipment, but the structure of the exposure light irradiation optical system is very simple, with high throughput and excellent cost performance. It can be done.
[0004]
In a proximity-type substrate exposure apparatus, a photomask can be appropriately held by a mask holder in a state where a predetermined minute proximity gap is opened in parallel to a glass substrate held below the photomask. is important. In other words, a small-sized photomask can be placed and held on the upper surface of the mask holder in which the opening for exposure is formed in the center thereof without any substantial problem. On the other hand, in a large-sized photomask, Since its own weight is large, when it is placed on the upper surface of the mask holder, its central portion bends downward. This amount of deflection increases as the size of the photomask increases in length and width. When the photomask is bent in this way, the proximity gap becomes smaller than a predetermined value, which causes the following inconvenience. That is, a photoresist film is formed on the upper surface of the glass substrate (that is, the surface facing the circuit pattern forming surface of the photomask), but when the photomask is largely bent downward, the photomask The proximity gap is not uniform between the central portion and the peripheral portion. In extreme cases, the central portion of the photomask may come into contact with the photoresist film and may become dirty or the circuit pattern may be peeled off. As a result, the circuit pattern is not properly baked on the glass substrate.
[0005]
As a technique for eliminating the downward deflection of the photomask as described above, the following has been proposed. That is, according to this proposed technique, the photomask is transported to the lower side of the substantially rectangular box-shaped mask holder opened downward through the cantilevered mask transport arm and pressed against the lower end surface of the mask holder. Then, it is held on the mask holder by vacuum suction. Then, by controlling the internal space of the mask holder to an appropriate negative pressure via an intake pipe connected to a vacuum source, the photomask is sucked upward so that downward deflection is corrected. Thus, the photomask is held by the mask holder in parallel with the underlying glass substrate and with a predetermined proximity gap, so that proper circuit pattern printing is possible.
[0006]
[Problems to be solved by the invention]
However, in the proposed technique, since the mask transport arm for transporting the photomask is a cantilever type, it is easy to bend downward, and when pressing the photomask against the lower end surface of the mask holder, The mask transfer arm is bent considerably. Further, since the mask transfer arm supports the photomask at the edge portion where there is no circuit pattern, the center portion of the photomask is also bent downward. Due to the bending of the mask transfer arm and the bending of the photomask, it is difficult to press the photomask transferred by the mask transfer arm accurately and in parallel to the lower end surface of the mask holder. Therefore, conventionally, it has been difficult to suck and hold the photomask in an appropriate state on the lower end surface of the mask holder. Further, since the position adjustment of the photomask in the horizontal direction with respect to the mask holder is performed by pushing the photomask with an air cylinder or the like, precise position adjustment is difficult.
[0007]
The present invention has been made in view of the above points, and an object thereof is to provide an exposure apparatus capable of appropriately holding a photomask on a mask holder with a simple configuration.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an alignment stage unit between a substrate held by an exposure chuck as a workpiece to be exposed and a photomask held by a mask holder immediately above the exposure chuck. An exposure apparatus that performs an exposure process on the substrate by performing control to ensure a predetermined proximity gap, and is provided at equal intervals on the outer peripheral edge of the exposure chuck, and is always above the outer peripheral edge. A plurality of temporary support members each having a buffer function, and a transport means for transporting a photomask to the alignment stage unit and placing the photomask on the plurality of temporary support members having the buffer function , and those placed so as to support from below the outer circumferential edge portion of the photomask by a plurality of the temporary support member, equiangular Three Z-axis direction driving mechanisms connected to the lower surface side of the exposure chuck in a state of being separated from each other by a distance, and each Z-axis direction is a direction to approach and retract the mask holder so as to be independently controllable The exposure chuck can be driven, whereby the exposure chuck can be driven so that the photomask supported by the plurality of temporary support members is parallel to a lower end surface of the mask folder ; An exposure apparatus comprising: an X, Y, and axial alignment stage that drives the exposure chuck in the X, Y, and axial directions, respectively.
According to this invention, the transport means transports the selected photomask to the alignment stage unit and places it on the temporary support member having a plurality of buffer functions provided in the exposure chuck. At this time, since the outer peripheral edge of the photomask is supported by a plurality of temporary support members, the photomask pattern is damaged by supporting the outer peripheral edge of the photomask on which the circuit pattern is not formed. There is no. Then, the exposure chuck is appropriately driven in the X, Y, and axial directions via the X, Y, and vertical axis alignment stages to correct a photomask conveyance shift, and further, three Z-axis direction driving mechanisms By independently controlling the drive, the photomask supported by a plurality of temporary support members is controlled so as to be parallel to the lower end surface of the mask folder, so that the photomask is relative to the mask holder. It may be so as to hold the photomask by a mask holder in a state corrects the Tsu row of horizontal posture so as to be parallel. Then, all the three Z-axis direction drive mechanisms are simultaneously driven to bring the exposure chuck close to the mask holder, thereby pressing the photomask on the temporary support member against the mask holder. At this time, the temporary support member can softly press the photomask against the mask holder by its buffer function, and as a result, the photomask is smoothly sucked and held by the mask holder. As described above, the photomask placed on the plurality of temporary support members provided in the exposure chuck is driven in the Z-axis direction via the three Z-axis direction driving mechanisms, so that the mask holder can be appropriately used. In the prior art, the X, Y, vertical axis alignment stage, and the three Z-axis direction driving mechanisms can drive the photomask transport displacement and the inclination of the mask holder. An air cylinder or the like separately provided for photomask position adjustment is not required, and the configuration is simple.
In the above apparatus, the plurality of temporary support members are a plurality of air cylinders, and the transfer means places the photomask on top ends of piston rods of the plurality of air cylinders.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a front view showing a main part of a proximity exposure apparatus according to an embodiment of the present invention. FIG. 2 is a plan view schematically showing the entire main part of the apparatus. As described above, the proximity exposure apparatus is configured so that a predetermined proximity gap is maintained between the photomask held by the mask holder and the substrate held by the exposure chuck as the workpiece to be exposed. It is an apparatus that performs control and performs an exposure process on the substrate.
[0010]
As is clear from FIG. 2, the mask transfer arm 2 is a substantially U-shaped cantilever arm when viewed in a plan view, as in the conventional example, and has a free end ( That is, the photomask 4 is placed and supported on the upper surface of the two arm portions facing in parallel. In this case, the mask transfer arm 2 supports the photomask 4 at the outer peripheral edge outside the circuit pattern formation region. The mask transfer arm 2 that supports the photomask 4 in this manner moves, for example, in the X direction in order to transfer the photomask 4 to a predetermined alignment stage unit AL. Further, the substrate transfer arm 6 moves, for example, in the Y direction in order to transfer the glass substrate 5 that is the workpiece to be exposed to the alignment stage unit AL.
[0011]
As shown in FIG. 1, the alignment stage unit AL includes an exposure chuck 8 and a mask holder 10 having a substantially rectangular box shape opened downward, and the mask holder 10 is positioned immediately above the exposure chuck 8. is doing. The upper end of the mask holder 8 is closed by an upper lid 8a such as a light-transmitting glass plate.
[0012]
The glass substrate 5 transported by the substrate transport arm 6 (FIG. 2) is placed on the exposure chuck 8 and held by suction on its non-exposed surface (in this case, the lower surface). On the other hand, the photomask 4 transported by the mask transport arm 2 (FIG. 2) is sucked and held on the lower end surface of the mask holder 10 on the non-circuit pattern forming surface (in this case, the upper surface), and is on the exposure chuck 8. The glass substrate 5 is kept facing the glass substrate 5. Reference numeral 12 denotes an air inlet formed in the mask holder 10 for attracting and holding the photomask 4. Reference numeral 14 denotes a mask holder support for fixing the mask holder 10 to a predetermined frame or the like of the apparatus. When the photomask 4 is sucked and held on the lower end surface of the mask holder 10 as described above, the internal space of the substantially rectangular box-shaped mask holder 10 is completely closed by the upper lid 8a and the photomask 4, In this state, an appropriate negative pressure is controlled through an intake pipe (not shown). By such negative pressure control, as in the conventional example, the photomask 4 can be sucked upward so that its downward deflection is appropriately corrected. In the above-described conventional example, the photomask cannot be properly held by suction on the mask holder due to the downward bending of the mask transfer arm and the downward bending of the photomask transferred by the mask transfer arm. However, in the embodiment of the present invention, the photomask 4 can be appropriately sucked and held on the mask holder 10 by the novel configuration described below.
[0013]
The exposure chuck 8 for holding the glass substrate 5 is connected on its lower surface to a Z-axis direction drive mechanism 14 (also referred to as a tilting Z mechanism in this field) consisting of a lifting motor or the like. Further, it is connected to a three-stage X, Y, θ-axis alignment stage 16 via the Z-axis direction drive mechanism 14. In the illustrated example, three Z-axis direction drive mechanisms that can be controlled independently (only two Z-axis direction drive mechanisms among the three Z-axis direction drive mechanisms are shown in FIG. 1) 14 are X, Y, The θ-axis direction alignment stage 16 is provided at equiangular intervals (120-degree intervals), and the exposure chuck 8 is supported by these three Z-axis direction drive mechanisms 14 at three points. Here, the Z-axis direction means a direction in which the mask holder 10 moves up and approaches and descends and retracts. As will be described later, these three Z-axis direction drive mechanisms 14 correct the inclination of the exposure chuck 8 with respect to the reference horizontal plane, that is, the horizontal posture, by the raising / lowering operation of the raising / lowering motor, thereby holding the exposure chuck 8 on the exposure chuck 8. A function of ensuring a predetermined minute (for example, several microns) proximity gap uniformly over the entire region between the glass substrate 5 to be formed and the photomask 4 held by suction on the lower end surface of the mask holder 10. To fulfill. The reference horizontal plane is a plane that is exactly parallel to the lower end surface of the mask holder 10.
[0014]
That is, for example, when the inclination of the exposure chuck 8 with respect to the reference horizontal plane, that is, the horizontal posture is not appropriate, the glass mask 5 held on the exposure chuck 8 and the photomask 4 held by suction on the lower end surface of the mask holder 10. Proximity gap between the two is inconvenient because the size (width in the vertical direction) becomes uneven depending on the area. Therefore, in addition to the normal function of raising and lowering the exposure chuck 8, the three Z-axis direction drive mechanisms 14 perform the function of controlling the horizontal posture of the exposure chuck 8 by being independently controlled in operation. . The X, Y, and θ axis direction alignment stage 16 moves the exposure chuck 8 in the X axis direction and Y axis direction (here, the front and back directions in the drawing) in the horizontal plane, and the Z axis (vertical axis). Is displaced by a desired distance or a desired angle in a desired direction in the rotation direction (ie, the θ-axis direction).
[0015]
According to an important feature of the present embodiment, a large number of air cylinders 18 as photomask temporary support members are attached to the outer peripheral edge of the exposure chuck 8 at predetermined equal intervals. The reason for using the air cylinder 18 as the photomask temporary support member is that the air cylinder 18 can perform an appropriate buffer function when the photomask 4 is pressed against the lower end surface of the mask holder 10 as will be described later. . More specifically, according to the present embodiment, the mask transport arm 2 that transports the photomask 4 to the lower side of the mask holder 10 in the alignment stage unit AL has an outer peripheral edge portion of the plurality of air cylinders 18. The photomask 4 is placed on the piston rods 18a of the multiple air cylinders 18 so that the upper ends of the piston rods 18a are supported at equal intervals.
[0016]
When it is detected by a gap detection sensor (not shown) that the photomask 4 placed on the piston rod 18a is not parallel to the lower end surface of the mask holder 10, the photomask 4 is By appropriately operating one of the Z-axis direction drive mechanism (tilting Z mechanism) 14 while being placed and supported on the piston rod 18a of the air cylinder 18, the exposure chuck 8 is placed in a horizontal posture. By appropriately adjusting, the photomask 4 on the air cylinder 18 fixed to the outer peripheral edge of the exposure chuck 8 is corrected to be parallel to the lower end surface of the mask holder 10. Further, it is an edge detection sensor (not shown) that the photomask 4 placed in this way is displaced (conveyed) in any of the X, Y, and θ axis directions with respect to the lower end surface of the mask holder 10. If detected, the horizontal position of the exposure chuck 8 with respect to the lower end surface of the mask holder 10 is adjusted by appropriately operating the X, Y, and θ-axis alignment stage 16, whereby the photomask 4. The conveyance deviation with respect to the lower end surface of the mask holder 10 is corrected. In this way, when the process of correcting the photomask 4 to a state in which the photomask 4 is not parallel to the lower end surface of the mask holder 10 and is parallel is completed, the three Z-axis direction drive mechanisms (tilting Z mechanism) are completed. ) 14 are simultaneously operated by the same amount, and the exposure chuck 8 and the air cylinder 18 attached to the exposure chuck 8 are raised, whereby the photomask 4 placed on the air cylinder 18 is It is pressed against the lower end surface of the mask holder 10 through the piston rods 18a of a large number of air cylinders 18 (shown by a two-dot chain line in FIG. 1). At the time of pressing, the air cylinder 18 can perform an appropriate buffer function by the air pressure.
[0017]
Next, an example of the operation of the proximity exposure apparatus according to the present embodiment having the above-described configuration will be described. The following description will be made on the assumption that the glass substrate 5 is not placed on the exposure chuck 8 as an initial state.
In the initial state as described above, the glass substrate 5 is transported to the alignment stage unit AL by the substrate transport arm 6 and is placed on the exposure chuck 8 on its non-exposed surface (lower surface). Then, the horizontal position of the glass substrate 5 on the exposure chuck 8 and the horizontal position with respect to the lower end surface of the mask holder 10 are corrected via the Z-axis direction drive mechanism 14 and the X, Y, and θ-axis direction alignment stage 16. Is done. That is, pre-alignment for correcting the transfer deviation of the glass substrate 5 is performed. When the posture and position are appropriately corrected in this way, the glass substrate 5 is sucked and held on the exposure chuck 8.
[0018]
Then, the mask transfer arm 2 transfers the selected photomask 4 to the alignment stage unit AL, and then the outer peripheral edge portion of the photomask 4 is placed on the upper ends of the piston rods 18a of a number of air cylinders 18. Then, the photomask 4 is unloaded. That is, the transported photomask 4 is first unloaded and placed on the upper end surface of the piston rod 18a of the air cylinder 18 disposed at a predetermined interval on the outer peripheral edge of the exposure chuck 8. The solid line in FIG. 1 shows a state immediately after the glass substrate 5 is sucked and held on the exposure chuck 8 and the photomask 4 is placed on the upper end of the piston rod 18 a of the air cylinder 18.
[0019]
When it is detected that the photomask 4 placed on the piston rod 18 a is not parallel to the lower end surface of the mask holder 10, the photomask 4 is placed on the piston rods 18 a of the multiple air cylinders 18. The photomask 4 on the air cylinder 18 fixed to the outer peripheral edge of the exposure chuck 8 is placed on the lower end surface of the mask holder 10 via the Z-axis direction drive mechanism 14 while being mounted and supported on the lower surface of the mask holder 10. Correct so that it becomes parallel. In addition, when the photomask 4 placed above is misaligned with respect to the lower end surface of the mask holder 10 in any of the X, Y, and θ axis directions, the X, Y, and θ axis direction alignment stage 16 is used. Then, the positional deviation of the photomask 4 with respect to the lower end surface of the mask holder 10, that is, the conveyance deviation is corrected.
[0020]
When the correction of the horizontal posture and conveyance deviation of the photomask 4 is completed as described above, the three Z-axis direction driving mechanisms 14 are simultaneously operated so that the exposure chuck 8 is raised by the same predetermined distance. As the exposure chuck 8 is lifted as described above, the photomask 4 is softly received by the mask holder 10 while receiving a buffering action by the piston rods 18a of the air cylinders 18, as indicated by a two-dot chain line. It is gradually pressed against the lower end surface of. As a result, the photomask 4 can be softly sucked and held in a state parallel to the lower end surface of the mask holder 10 and without being misaligned.
[0021]
In the above embodiment, the photomask 4 transported to the alignment stage unit AL by the mask transport arm 2 is first configured on the upper ends of the piston rods 18a of a number of air cylinders 18. 4 may be a photomask temporary support member having a buffering function by an action other than air pressure, for example, a member biased by a spring. In any case, in the present invention, photomask temporary support members having a buffer function are provided at equal intervals on the outer peripheral edge of the exposure chuck 8.
Furthermore, the workpiece to be exposed handled by the apparatus of the present invention is not limited to a glass substrate, but may be a flat plate to be subjected to other exposure processing.
[0022]
【The invention's effect】
As described above, the exposure apparatus according to the present invention has an excellent effect that the photomask can be appropriately held by the mask holder with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a front view showing a main part of a proximity exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a plan view schematically showing an entire main part of the apparatus.
[Explanation of symbols]
2 Mask transfer arm 4 Photomask 5 Glass substrate 8 Exposure chuck 14 Z axis direction drive mechanism 16 X, Y, θ axis direction alignment stage 18 Air cylinder (temporary support member)
AL alignment stage unit

Claims (2)

In the alignment stage unit, control is performed to ensure a predetermined proximity gap between the substrate held on the exposure chuck as a workpiece to be exposed and the photomask held on the mask holder immediately above the exposure chuck. In an exposure apparatus that performs an exposure process on the substrate,
A plurality of temporary support members which are provided at equal intervals on the outer peripheral edge of the exposure chuck and which always protrude upward from the outer peripheral edge, each having a buffering function;
Transport means for transporting the photomask to the alignment stage unit and placing it on the plurality of temporary support members having the buffer function, and supporting the outer peripheral edge of the photomask from below by the plurality of temporary support members To be placed so that
Three Z-axis direction drive mechanisms connected to the lower surface side of the exposure chuck in a state of being spaced apart at equal angular intervals, each Z being a direction to approach and retract the mask holder so as to be independently controllable. The exposure chuck can be driven in the axial direction, and thereby the exposure chuck can be driven so that the photomask supported by the plurality of temporary support members is parallel to the lower end surface of the mask folder. When,
An exposure apparatus comprising: an X, Y, and axial alignment stage that drives the exposure chuck in the X, Y, and axial directions, respectively.   The exposure apparatus according to claim 1, wherein the plurality of temporary support members are a plurality of air cylinders, and the transport unit places the photomask on tip ends of piston rods of the plurality of air cylinders.

Images