JP2020194192A - Method for absorbing and holding workpiece, workpiece stage and exposure apparatus - Google Patents

Abstract

To provide an inexpensive workpiece stage capable of sufficiently absorbing and holding a deformed workpiece without damaging the workpiece, and easily corresponding with workpieces having different sizes.SOLUTION: A shrinkable sheet 3 disposed on a workpiece holding surface of a stage body 1 on which a plate-like workpiece W is placed has a frame shape of surrounding an area in which a workpiece vacuum adsorption hole 21 is disposed. When the workpiece W is placed on the workpiece holding surface and is absorbed by vacuum suction through the workpiece vacuum adsorption hole 21, the shrinkable sheet 3 is sandwiched between the workpiece W and the stage body 1. The shrinkable sheet 3 has a shape extending along the peripheral part of the workpiece W, and shrinks in a thickness direction due to elasticity in accordance with the deformation of the workpiece W, and comes in close contact with the workpiece W.SELECTED DRAWING: Figure 5

Description

The invention of the present application relates to a work stage for holding a work to be processed in a predetermined position, and also relates to an exposure apparatus equipped with this type of work stage.

In an apparatus that performs various processes, it is often necessary to hold an object to be processed (hereinafter referred to as a work) in a predetermined position. At this time, when the work is plate-shaped, it is often placed on a trapezoidal member having a flat surface (hereinafter referred to as a stage) and held, and such a stage is called a work stage.
The work stage is often provided with a mechanism for sucking the work in order to ensure the holding of the work, and a vacuum suction mechanism for sucking the work by vacuum is often adopted for this mechanism. A vacuum suction hole is formed on the work holding surface of the work stage, and a vacuum exhaust path communicating with the vacuum suction hole is provided in the work stage. A vacuum pump is connected to the vacuum exhaust passage, and the work is held on the work stage by vacuum suctioning through the vacuum suction hole in a state where the work is arranged so as to close the vacuum suction hole.

JP-A-2009-1095553 Japanese Unexamined Patent Publication No. 2011-0811156 Japanese Patent No. 4589198 Japanese Unexamined Patent Publication No. 2014-072510 Japanese Unexamined Patent Publication No. 2016-111433

In a work stage provided with such a vacuum suction mechanism, the work is deformed, and there is a problem that vacuum suction cannot be sufficiently performed due to this.
For example, in an exposure apparatus for a printed circuit board that exposes a circuit pattern to a substrate, a work stage is used to hold the substrate at a predetermined position with respect to an exposure optical system. Such an exposure apparatus for a printed circuit board may expose a thin and flexible substrate made of polyimide, polyester, or the like. This type of substrate is susceptible to the heat treatment in the previous process and may be curved or wavy when viewed from the side. Even in the case of a rigid substrate such as glass epoxy, if the substrate has a multi-layer structure, the peripheral portion of the substrate will be warped or curved as the laminating process is repeated due to the difference in the coefficient of thermal expansion between the materials. Is likely to occur.

When the work is deformed such as warped or curved, when it is placed on the work stage, the vacuum suction holes cannot be sufficiently closed and the vacuum leaks, so that vacuum suction cannot be performed or suction is performed. Is insufficient. As a result, the work can be displaced during processing. In the case of an exposure apparatus, the displacement of the workpiece during exposure directly leads to a decrease in the positional accuracy of the exposed pattern, which affects the performance of the product. Therefore, it is necessary to be able to sufficiently vacuum-suck the work in which such deformation occurs.

As a conventional configuration for sufficiently vacuum suctioning a deformed work, a clamp mechanism for pressing the peripheral portion of the work from above is often adopted. However, this kind of mechanism has a drawback that it easily damages the work. In addition, since the peripheral part of the work is covered from above, if it is necessary to perform processing (for example, exposure) on the peripheral part as well, it is necessary to retract the clamp during the processing, and when retracted, the workpiece is the original. There may be a problem that the vacuum leaks due to the return to the deformed posture of. Further, this type of mechanism tends to be complicated, the device becomes large, and the cost tends to be high.

In addition, it is often necessary to process workpieces of different sizes with one device under the demand for high-mix low-volume production. In this case, in the case of the clamp mechanism, it is difficult to handle workpieces of different sizes, and there is a problem that the mechanism becomes more complicated and the cost becomes higher in order to make this possible.
The invention of the present application has been made to solve each of the above problems, and it is possible to sufficiently adsorb and hold a deformed work, and at this time, there is a problem of damaging the work. The purpose is to make it easy to handle workpieces of different sizes and to realize it at a lower cost.

In order to solve the above problems, the invention according to claim 1 of the present application is a plate-shaped work having a vacuum suction hole, which is deformed due to warping or bending when traced in the circumferential direction in the peripheral portion. It is a work suction holding method that holds the work by vacuum sucking it on the stage.
The work stage is
A stage body having a vacuum suction hole for the work on the work holding surface,
It is equipped with an exhaust system that sucks the work by vacuum sucking the vacuum suction holes for the work when the work comes into contact with the work at the holding position set on the work holding surface.
A shrink sheet is provided on the work holding surface,
The shrink sheet has a shape that surrounds the area outside the area provided with the vacuum suction hole for the work, and when the work comes into contact with the work holding surface at the holding position, the work and the work holding surface of the stage body are brought into contact with each other. It has a shape that extends along the peripheral part of the work while being sandwiched between them.
The shrink sheet has elasticity due to elasticity that contracts in the thickness direction when the work in contact with the work holding surface is vacuum-sucked and adheres to the work, and the flexibility is the deformation of the peripheral portion of the work. It is a shrinkage property that contracts to different thicknesses according to the above and traces the deformation of the work, and the deformation and shrinkage to different thicknesses are the deformation in the circumferential direction of the peripheral portion of the work and the deformation to different thicknesses. Including shrinkage,
The shrink sheet has a thickness exceeding the maximum amount of deformation in the thickness direction of the work.
The contracted shrink sheet fills the space between the work holding surface of the work stage and the deformed work, thereby sealing the space facing the vacuum suction hole for the work.
Further, in order to solve the above problems, the invention according to claim 2 is a work stage for holding a plate-shaped work.
A stage body having a vacuum suction hole for the work on the work holding surface,
It is a work stage equipped with an exhaust system that sucks the work by vacuum sucking the vacuum suction holes for the work when the work comes into contact with the work at the holding position set on the work holding surface.
A shrink sheet is provided on the work holding surface,
The shrink sheet has a shape that surrounds the area outside the area provided with the vacuum suction hole for the work, and when the work comes into contact with the work holding surface at the holding position, the work and the work holding surface of the stage body are brought into contact with each other. It has a shape that extends along the peripheral part of the work while being sandwiched between them.
The shrink sheet has elasticity due to elasticity that contracts in the thickness direction when the work in contact with the work holding surface is vacuum-sucked and adheres to the work, and the flexibility is the deformation of the peripheral portion of the work. It is a shrinkage property that contracts to different thicknesses according to the above and traces the deformation of the work, and the deformation and shrinkage to different thicknesses are the deformation in the circumferential direction of the peripheral portion of the work and the deformation to different thicknesses. Including shrinkage,
The shrink sheet has a thickness exceeding the maximum amount of deformation in the thickness direction of the work.
The shrink sheet is detachably attached to the work holding surface,
The shrink sheet has a frame-like shape, and the inner edge of the shrink sheet is located inside the holding area, which is the area occupied by the work when the work is held, and the shrink sheet is outside the holding area. It has a configuration in which the outer edge of is located.
Further, in order to solve the above problems, the invention according to claim 3 has the configuration of claim 2, wherein the shrink sheet is the entire circumference of the peripheral portion of the work in contact with the work holding surface at the holding position. Has a configuration in which it has a shape that overlaps with the work.
Further, in order to solve the above problems, in the invention of claim 4, in the configuration of claim 2, the shrinkage sheet is partially located at a peripheral portion of the work in contact with the work holding surface at the holding position. The shape has a region that does not overlap with the above, and the length of the non-overlapping region in the circumferential direction is 10 mm or less.
Further, in order to solve the above problems, the invention according to claim 5 shrinks in the thickness direction when the work in contact with the work holding surface is vacuum-sucked in the configuration of claims 2, 3 or 4. The average thickness of the shrinking sheet is 0.5 mm or less.
Further, in order to solve the above problems, in the invention according to claim 6, in the configuration of any one of claims 2 to 5, the stage body has a flat surface outside the region provided with the vacuum suction hole for the work. It has a structure in which the shrinkage sheet is provided on the flat surface.
Further, in order to solve the above problems, the invention according to claim 7 is an invention of an exposure apparatus.
Light source and
An optical system that projects light from a light source as an image of a predetermined pattern,
The work stage according to any one of claims 2 to 6 is provided, and the holding position is a projection position of an image of a predetermined pattern by an optical system.
Further, in order to solve the above problems, the invention according to claim 8 is made in the configuration of claim 7.
The average thickness of the shrinking sheet that shrinks in the thickness direction when the work in contact with the work holding surface is vacuum-adsorbed is 1/2 or less of the depth of focus when the optical system projects the image. It has a configuration of.

As described below, according to the invention according to claim 1 or 2 of this application, when the work is vacuum-adsorbed to the work stage, the shrinkage sheet is compressed in the thickness direction by the peripheral portion of the work and shrinks. Even for a deformed work, the shrinkage sheet and the work are in close contact with each other, and an error of vacuum suction is prevented. At this time, unlike the clamp mechanism, it is not necessary to press the work from the opposite side, so that the work is not damaged, the structure is simple, and the cost is low.
Further, according to the invention of claim 5, in addition to the above effect, since the average thickness of the shrunk shrink sheet is 0.5 mm or less, the curvature of the vacuum-adsorbed work is reduced.
Further, according to the invention of claim 6, in addition to the above effect, since the shrinkage sheet is provided on the flat surface of the stage body, it is easy to deal with workpieces having different shapes and sizes. Be done.
Further, according to the invention of claim 7, the above effect can be obtained in an exposure apparatus that exposes a work.
Further, according to the invention of claim 8, in addition to the above effect, since the average thickness of the shrunk shrink sheet is ½ or less of the depth of focus of the optical system, the above effect is prevented while preventing blurring of the image. Can be obtained.

It is a front sectional schematic drawing of the work stage of an embodiment. It is a perspective schematic view of the work stage shown in FIG. It is a perspective schematic view of the main part of the work stage shown in FIG. It is a cross-sectional schematic diagram which showed the flexibility which a shrink sheet has, and is the cross-sectional schematic diagram in XX of FIG. It is the cross-sectional schematic diagram which showed the flexibility which a shrinkage sheet has, and is the cross-sectional schematic diagram in YY of FIG. It is a front sectional schematic diagram of the exposure apparatus of embodiment.

Next, a mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described. The following description includes a description of an embodiment of the invention of the work suction holding method and a description of the embodiment of the invention of the work stage.
FIG. 1 is a schematic front sectional view of the work stage of the embodiment, FIG. 2 is a schematic perspective view of the work stage shown in FIG. 1, and FIG. 3 is a schematic perspective view of a main part of the work stage shown in FIG.
The work stage of the embodiment shown in FIGS. 1 to 3 is a stage for holding a plate-shaped work W, and includes a stage main body 1. The stage body 1 is a trapezoidal member having a rectangular plan view. In this embodiment, the stage body 1 holds the work W in a horizontal posture, and the upper surface, which is a horizontal flat surface, is the work holding surface.

As shown in FIGS. 1 to 3, the stage body 1 has a plurality of vacuum suction holes 21 for workpieces. The holding position of the work W is set on the upper surface of the stage main body 1, and the vacuum suction hole 21 for the work is provided at the holding position.
As shown in FIG. 1, a work exhaust passage 22 communicating with each work vacuum suction hole 21 is formed in the stage main body 1. The work stage includes an exhaust system 2 including a vacuum pump (not shown), and the work exhaust pipe 23 of the exhaust system 2 is connected to the work exhaust passage 22.

The work stage of such an embodiment is provided with a shrink sheet 3 in consideration of the problem of deformation of the work W. The shrink sheet 3 has a square frame shape as shown in FIGS. 2 and 3. In FIG. 3, some members are omitted in order to make it easier to understand the overall shape of the shrink sheet 3.
The shrinkage sheet 3 is provided in a state of being placed on the upper surface of the stage main body 1. The mounting position is a predetermined position in relation to the holding position of the work W.
In this embodiment, the work W has a rectangular plate shape. The holding position is set, for example, as a position where the held work W occupies a rectangular area concentric with the center of the stage body 1. The holding position is shown by a square imaginary line R in FIGS. 2 and 3. The work W is placed with high accuracy so that its contour coincides with the imaginary line R. The area surrounded by the imaginary line R is hereinafter referred to as a holding area.

The shrinkage sheet 3 is provided at a position where the peripheral portions of the work W overlap when the work W is placed at the holding position, and therefore is sandwiched between the work W and the work holding surface of the stage body 1. Will be. More specifically, the inner edge of the shrink sheet 3 is located inside the holding region R, and the outer edge is located outside the holding region R. Therefore, when the work W is arranged so that the contour of the work W coincides with the holding region R, the shrinking sheet 3 is sandwiched between the work W and the work holding surface of the stage body 1, and the entire circumference of the peripheral edge of the work W In the state where it overlaps with the work W. Therefore, the shrink sheet 3 has a square frame shape in which the inner edge and the outer edge are parallel to each side (hereinafter, such a shape is referred to as a frame shape in the present specification).
As such a shrinkage sheet 3, one made of silicone is used in this embodiment. The thickness is preferably 0.1 to 10 mm, more preferably about 0.5 to 2 mm.

The shrink sheet 3 has the flexibility of shrinking in the thickness direction when the work W in contact with the work holding surface is vacuum-adsorbed and is in close contact with the work W, and this shrinkage prevents vacuum leakage. It has become so. Hereinafter, this point will be described with reference to FIGS. 4 and 5. 4 and 5 are schematic cross-sectional views showing the flexibility of the shrink sheet 3. FIG. 4 is a schematic cross-sectional view taken along the line XX of FIG. 2, and FIG. 5 is a schematic cross-sectional view taken along the line YY. 4 (1) and 5 (1) show a state before the work W is held on the work stage, and FIGS. 4 (2) and 5 (2) show a vacuum in which the work is held on the work stage. Indicates the adsorbed state.

The work W is placed and held at the holding position of the stage body 1. At this time, the work W comes into contact with the stage body 1 at the holding position, and the work vacuum suction hole 21 is closed. Then, the work vacuum suction hole 21 is evacuated by a vacuum pump (not shown) provided in the exhaust system 2, so that the work W is evacuated to the stage body 1 as shown in FIG. 4 (2).
At this time, as shown in FIG. 5 (2), the shrinking sheet 3 overlapping the peripheral portion of the work W shrinks in the thickness direction according to the shape of the deformed work W. The cross-sectional shape of the shrinkage sheet 3 after shrinkage is similar to the cross-sectional shape of the deformed work W, and the work W and the shrinkage sheet 3 are in close contact with each other. As a result, the space inside the shrink sheet 3 becomes a closed space (sealed space) due to the close contact between the work W and the shrink sheet 3, and vacuum leakage is prevented.

As described above, the flexibility of the shrinkage sheet 3 is such that the work W can compress the shrinkage sheet 3 and adhere to it when vacuum sucked. The shrinkage sheet 3 of the embodiment is made of silicone, but the one sold as a so-called silicone rubber sheet can be shrunk by the suction force when the work W is vacuum-adsorbed, and the shrinkage sheet of the embodiment It can be used as 3. For example, an SR sheet manufactured by Tigers Polymer Co., Ltd. can be used as the shrink sheet 3 in the embodiment. The suction force applied to the work W during vacuum suction is generally about -50 kPa to -80 kPa, and it can be said that the work W has flexibility to contract with such a force.

The thickness of the shrinkage sheet 3 is selected according to the amount of deformation of the work W in the thickness direction. The thickness of the shrinkage sheet 3 needs to exceed the maximum amount of deformation of the work W in the thickness direction. For example, when the thickness of the work W is 0.3 mm and the maximum deformation amount is 0.7 mm, the thickness of the shrinkage sheet 3 is about 1 mm.
It is necessary that the compression of the shrinkage sheet 3 according to the deformation of the work W is not a plastic deformation but an elastic deformation. However, since the shrinkage sheet 3 may be restored to its original state by the time the next work W is vacuum-adsorbed, it may exhibit so-called low resilience.

Such a shrink sheet 3 is attached in a state where it is not displaced with respect to the stage body 1 (a state in which the position is fixed). In this embodiment, the shrinkage sheet 3 is vacuum-adsorbed to the stage body 1. As shown in FIG. 1, the stage main body 1 is provided with a vacuum suction hole 24 for a sheet. The vacuum suction hole 24 for the sheet communicates with the exhaust passage 25 of a system different from the vacuum suction hole 21 for the work, and the exhaust and the opening to the atmosphere are controlled independently. That is, the seat exhaust pipe 26, which is different from the work exhaust pipe 23, is connected to the seat exhaust passage 25 formed so as to communicate with the seat vacuum suction hole. On the seat exhaust pipe 26, an on-off valve and an air release valve are provided in addition to those on the work exhaust pipe 23.

Further, in this embodiment, as shown in FIGS. 1 and 2, the shrinkage sheet 3 is provided in a state of being stretched on the frame body 31. It is not always necessary for the shrink sheet 3 to include the frame 31, but the frame 31 is provided for ease of handling and for alignment.
The frame 31 is a metal plate-shaped member such as aluminum or stainless steel. In this embodiment, the frame 31 is also frame-shaped in accordance with the frame-shaped shrink sheet 3. The frame body 31 is thinned along the inner edge to form a step, and the outer edge of the shrinkage sheet 3 is fixed at this portion. Fixing is performed by, for example, bonding with an adhesive.

The shape and size of the outer edge of the frame 31 are the same as the contour shape and size of the stage body 1. Therefore, by aligning the outer edge of the frame 31 on which the shrink sheet 3 is stretched with the edge of the stage body 1 and placing the shrink sheet 3 on the stage body 1, the alignment of the shrink sheet 3 is completed. In order to further facilitate the alignment, a plurality of positioning plates 32 are provided on the edge of the stage body 1.

The vacuum suction for fixing the position of the shrinkage sheet 3 described above is directly performed on the frame 31. That is, the vacuum suction hole 24 for the sheet is formed at a position facing the frame body 31 placed so as described above, and the frame body 31 is directly vacuum sucked. There is. The shrinkage sheet 3 may be directly vacuum-adsorbed, but if the shrinkage sheet 3 is repeatedly vacuum-adsorbed, it may be worn out, which may cause a problem in terms of durability.

According to the work stage of the above embodiment, when the work W is vacuum-sucked to the work stage, the shrinkage sheet 3 is compressed in the thickness direction by the peripheral portion of the work W and contracted as described above. Since this shrinkage depends on the shape of the work W in the thickness direction, the shrinkage sheet 3 and the work W are in close contact with each other even if the work W is deformed in the thickness direction. Therefore, even if the work W is deformed, the error of vacuum suction is prevented, and appropriate processing is performed without being displaced in the work stage.
At this time, unlike the clamp mechanism, it is not necessary to press the work W from the opposite side, so that the work W is not damaged. Further, since the above effect is achieved by a simple structure in which the shrinkage sheet 3 is interposed between the work W and the stage main body 1 at the peripheral edge of the work W, it does not become a large scale and is inexpensive. It has become.

Further, since the shrink sheet 3 is removable, it is easy to deal with cases where the dimensions and shapes of the work W are different. That is, if the shape and / or size of the work W is different, the shrink sheet 3 is replaced. After stopping the vacuum suction by the vacuum suction hole 24 for the sheet, the shrinking sheet 3 is pulled away from the stage main body 1 by holding the frame body 31. Then, the shrinkage sheets 3 having different shapes and / or sizes are similarly positioned by the frame body 31 and installed on the stage main body 1, and the positions are fixed by vacuum suction in the vacuum suction holes 24 for the sheets.
Although it is possible to implement the structure in which the frame body 31 is detachably fixed to the stage body 1 by screwing, the replacement work is easier in the structure in which the position is fixed by vacuum suction.

In the above embodiment, the shrinkage sheet 3 is made of silicone, but a sheet made of another material can be used as long as it is elastically deformed and has the flexibility to adhere to the work W. The material of the shrink sheet 3 is preferably conductive. When the work W is repeatedly adsorbed and held and the work W is picked up after the treatment, the shrinkage sheet 3 may be charged (peeling charge or the like). The charge may attract surrounding dust, or an electric discharge may occur to damage the work W. When the shrinkable sheet 3 is conductive, the stage body 1 is normally grounded, so that even if it is charged, the charge is easily released and a problem is unlikely to occur. Since various conductive silicone rubber sheets are commercially available, they can be appropriately selected and used.

It is desirable that the average thickness of the contracted sheet 3 in the compressed state when the work W is vacuum-sucked is thin. This is because if the thickness at the time of compression is large, the work W is in close contact with the stage body at the central portion, so that the curvature of the work W becomes large (the curvature becomes small). Specifically, the average thickness of the compressed sheet 3 during compression is preferably 0.5 mm or less.

It is desirable that the shrink sheet 3 overlaps with the work W on the entire circumference of the peripheral portion of the work W. However, the invention of the present application can be carried out even if there are some places where they do not overlap. For example, it is assumed that the shrink sheet 3 has a shape having a substantially frame shape but having at least one interrupted portion. When the shrinkage sheet 3 shrinks in the thickness direction, it may be preferable to allow elongation in the circumferential direction, and a portion may be intentionally interrupted. Even in such a case, if such a break is a short distance, the space inside the shrink sheet 3 becomes a lower pressure than the atmosphere due to the decrease in conductance, so that the work W can be vacuum-sucked and deformed. Vacuum suction is also possible for the work W. The short distance can be, for example, 10 mm or less.

Further, when the work W is deformed only at a specific place in the circumferential direction, the shrinkage sheet may overlap with the work W only at that place, and in this case as well, the shrinkage sheet has an unterminated circumferential shape. There is no need.
It is desirable that the area where the shrink sheet 3 and the work W overlap includes the peripheral edge of the work W, but it can be implemented even if the area overlaps with the peripheral portion slightly inside the peripheral edge. However, if the shrink sheet 3 overlaps the vacuum suction hole 21 for the work, the vacuum suction of the work W is hindered. Therefore, it is necessary not to overlap the vacuum suction hole 21 for the work.

Further, as described above, it is desirable that the shrinkage sheet 3 is provided on the flat surface of the stage body 1. Although the present invention can be implemented in a structure in which a recess is provided in the stage body 1 and the shrink sheet 3 is placed in a state where the shrink sheet 3 is dropped and the thickness of the shrink sheet 3 is larger than the depth of the recess, a different shape and / or It becomes difficult to handle the size work W.

Next, as an example of using the work stage of the embodiment, an embodiment of the invention of the exposure apparatus equipped with the work stage will be described.
FIG. 6 is a schematic front sectional view of the exposure apparatus of the embodiment. The exposure apparatus shown in FIG. 6 is, for example, an exposure apparatus for a printed circuit board.
The exposure apparatus shown in FIG. 6 includes a work stage 4 that holds the work W at a predetermined position, an exposure system 5 that irradiates the work W held by the work stage 4 with light of a predetermined pattern to expose the work W, and a transport system 6. And have. The exposure system includes a light source and an optical system that projects light from the light source as an image of a predetermined pattern.

The exposure apparatus of the embodiment does not particularly select the exposure method, and any method of projection exposure, contact or proximity exposure, and DI (direct imaging) exposure can be adopted. For example, in the case of projection exposure, the exposure system 5 is composed of a light source, a mask irradiated with light from the light source, an optical system that projects an image of the mask on the work stage 4, and the like. In the case of DI exposure, a configuration in which a plurality of exposure units equipped with a laser light source and a space modulation element such as a DMD (Digital Mirror Device) that spatially modulates the light from the laser light source to form a pattern is provided. Will be adopted.

As the transport system 6, in this embodiment, a combination of a conveyor and a transport hand is adopted. Conveyors 61 and 62 are provided on both sides of the work stage 4. The transfer conveyors 61 and 62 are for loading and unloading the work W to the work stage 4, and for convenience of explanation, the transfer conveyor 61 on the right side is used as the first transfer conveyor and the transfer conveyor 62 on the left side is used as the second transfer conveyor. ..
Conveyors 63 and 64 are provided on both sides of the work stage 4 so as to operate in cooperation with the conveyors 61 and 62. Regarding the transport hands 63 and 64, for convenience of explanation, the transport hand 63 on the right side is referred to as the first transport hand, and the transport hand 64 on the left side is designated as the second transport hand.

Each of the transport hands 63, 64 includes frames 631, 641 and work suction pads 632, 642 attached to the frames 631, 641. Each frame 631, 641 is provided with a transport drive mechanism 633, 643. Although the details of the transport drive mechanisms 633 and 643 are not shown, the frames 631, 641 can be linearly moved in the transport direction (left-right direction on the paper surface of FIG. It is a mechanism. The device includes a control unit (not shown), and each transport drive mechanism 633, 643 is controlled by a control unit (not shown).

A plurality of work suction pads 632 and 642 are provided at equal intervals so as to suck the work W in the peripheral portion. A work suction source (not shown) is connected to each work suction pad 632, 642. The on / off of the work suction source is also controlled by a control unit (not shown).
The work stage 4 is provided with an elevating mechanism 40. The elevating mechanism 40 is driven when the work W is delivered, and is also used for the purpose of adjusting the distance of the work W with respect to the exposure system 5. The elevating mechanism 40 is composed of a linear motion mechanism including a servomotor, and is controlled by a control unit.

Next, the operation of the exposure apparatus of such an embodiment will be described.
First, the first transfer conveyor 61 conveys the work W to a position below the first transfer hand 63. Then, the first transport hand 63 is lowered to suck and hold the work W. After ascending by a predetermined distance, the first transport hand 63 moves in the horizontal direction and reaches an upper position of the work stage 4. After that, the first transport hand 63 descends by a predetermined distance, and the work W is placed on the work stage 4.

The first transfer hand 63 has the work W slightly pressed against the upper surface of the stage body 1, and in this state, the opening / closing valve on the work exhaust pipe 23 is opened to evacuate the work vacuum suction hole 21 to evacuate the work. W is vacuum-adsorbed. A little later than this timing, the first transfer hand 63 releases the suction of the work W, releases the work W, and rises.
The first transport hand 63 returns to the initial standby position. In parallel, the exposure system 5 operates, and the work W is irradiated with light of a predetermined pattern to perform exposure. After the exposure for a predetermined time, the second transfer hand 64 is positioned above the work stage 4, then descends by a predetermined distance to suck the work W. The opening / closing valve on the work exhaust pipe 23 is closed, the atmosphere release valve is opened, and the work exhaust passage 22 is opened to the atmosphere with a slight delay from the suction of the work W. As a result, the vacuum suction of the work W is released.

After that, the second transfer hand 64 moves up to the upper part of the second transfer conveyor 62 after rising by a predetermined distance. Then, the second transfer hand 64 descends by a predetermined distance, places the work W on the second transfer conveyor 62, and then releases the suction of the work W. The second transfer conveyor 62 carries out the work W to a position for the next processing or operation. Such an operation is repeated, and the work W is exposed one by one.

In the exposure apparatus of the embodiment, since the shrink sheet 3 prevents the vacuum leak at the time of vacuum suction of the work W as described above, the vacuum suction does not cause an error and the pattern is always projected at an accurate position. It can be performed. Therefore, the quality of the product is maintained high.
The above-described embodiment is an exposure apparatus for a printed circuit board, but in addition to this, if the object is a plate-shaped work W such as an exposure apparatus for a liquid crystal display, the same applies to other exposure apparatus. it can. Further, examples of use of the work stage 4 other than the exposure apparatus include a substrate inspection apparatus, a silk printing apparatus, a drilling apparatus, and the like.

When the work stage 4 of the embodiment is adopted in the exposure apparatus, the average thickness of the shrinkage sheet 3 shrunk during vacuum suction of the work W is 1 of the depth of focus when the image is projected by the optical system. It is preferably 1/2 or less.
In the work stage of the embodiment, the shrinkage sheet 3 is sandwiched between the stage body 1 and the work W, so that the work stage is brought closer to the optical system by the thickness of the shrinkage sheet 3 at that portion. Therefore, if the thickness of the shrunk sheet 3 is thicker than 1/2 of the depth of focus, the image is likely to be blurred. The peripheral portion of the work W in which the shrink sheet 3 is interposed is often an unused area (outside the area where the pattern should be projected in the work W), but in the case of the used area, the exposure pattern is blurred. This can cause product defects. Therefore, it is preferably 1/2 or less of the depth of focus.

1 Stage body 2 Exhaust system 21 Vacuum suction hole for work 24 Vacuum suction hole for sheet 3 Shrink sheet 31 Frame body 4 Work stage 5 Exposure system 6 Conveyance system W work

Claims (8)

This is a work suction holding method in which a plate-shaped work that is warped or curved and deformed when traced in the circumferential direction in the peripheral portion is vacuum sucked and held on a work stage having a vacuum suction hole.
The work stage is
A stage body having a vacuum suction hole for the work on the work holding surface,
It is equipped with an exhaust system that sucks the work by vacuum sucking the vacuum suction holes for the work when the work comes into contact with the work at the holding position set on the work holding surface.
A shrink sheet is provided on the work holding surface,
The shrink sheet has a shape that surrounds the area outside the area provided with the vacuum suction hole for the work, and when the work comes into contact with the work holding surface at the holding position, the work and the work holding surface of the stage body are brought into contact with each other. It has a shape that extends along the peripheral part of the work while being sandwiched between them.
The shrink sheet has elasticity due to elasticity that contracts in the thickness direction when the work in contact with the work holding surface is vacuum-sucked and adheres to the work, and the flexibility is the deformation of the peripheral portion of the work. It is a shrinkage property that contracts to different thicknesses according to the above and traces the deformation of the work, and the deformation and shrinkage to different thicknesses are the deformation in the circumferential direction of the peripheral portion of the work and the deformation to different thicknesses. Including shrinkage,
The shrink sheet has a thickness exceeding the maximum amount of deformation in the thickness direction of the work.
A work suction holding method characterized in that a space facing a vacuum suction hole for a work is sealed by filling a space between a work holding surface of the work stage and a deformed work with a shrunk shrink sheet. .. A work stage that holds a plate-shaped work
A stage body having a vacuum suction hole for the work on the work holding surface,
It is a work stage equipped with an exhaust system that sucks the work by vacuum sucking the vacuum suction holes for the work when the work comes into contact with the work at the holding position set on the work holding surface.
A shrink sheet is provided on the work holding surface,
The shrink sheet has a shape that surrounds the area outside the area provided with the vacuum suction hole for the work, and when the work comes into contact with the work holding surface at the holding position, the work and the work holding surface of the stage body are brought into contact with each other. It has a shape that extends along the peripheral part of the work while being sandwiched between them.
The shrink sheet has elasticity due to elasticity that contracts in the thickness direction when the work in contact with the work holding surface is vacuum-sucked and adheres to the work, and the flexibility is the deformation of the peripheral portion of the work. It is a shrinkage property that contracts to different thicknesses according to the above and traces the deformation of the work, and the deformation and shrinkage to different thicknesses are the deformation in the circumferential direction of the peripheral portion of the work and the deformation to different thicknesses. Including shrinkage,
The shrink sheet has a thickness exceeding the maximum amount of deformation in the thickness direction of the work.
The shrink sheet is detachably attached to the work holding surface,
The shrink sheet has a frame-like shape, and the inner edge of the shrink sheet is located inside the holding area, which is the area occupied by the work when the work is held, and the shrink sheet is outside the holding area. A work stage characterized by the location of the outer edge of the. The work stage according to claim 2, wherein the shrink sheet has a shape that overlaps with the work on the entire circumference of a peripheral portion of the work that is in contact with the work holding surface at the holding position. The shrink sheet has a shape having a region that does not partially overlap in the peripheral portion of the work that is in contact with the work holding surface at the holding position, and the length of the non-overlapping region in the circumferential direction is 10 mm or less. The work stage according to claim 2, wherein the work stage is provided. Claims 2, 3 or 4 are characterized in that the average thickness of the shrunk sheet shrunk in the thickness direction when the work in contact with the work holding surface is vacuum-adsorbed is 0.5 mm or less. The work stage described. Any of claims 2 to 5, wherein the stage body has a flat surface outside the region provided with the vacuum suction hole for the work, and the shrink sheet is provided on the flat surface. Work stage described in the crab. Light source and
An optical system that projects light from a light source as an image of a predetermined pattern,
An exposure apparatus comprising the work stage according to any one of claims 2 to 6, wherein the holding position is a projection position of an image of a predetermined pattern by an optical system. The average thickness of the shrinking sheet that shrinks in the thickness direction when the work in contact with the work holding surface is vacuum-adsorbed is 1/2 or less of the depth of focus when the optical system projects the image. 7. The exposure apparatus according to claim 7.

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