JP4535972B2 - Work stage and exposure apparatus - Google Patents

Description

  The present invention allows a gas to be blown from the upper surface to a substrate supported above, and simultaneously sucks the gas to balance the blowing and sucking of the gas to generate a predetermined gas layer between the upper surface and the substrate. More specifically, the present invention relates to a work stage and an exposure apparatus that enable uniform exposure by suppressing generation of distortion on the substrate surface.

As shown in FIG. 4, the conventional work stage includes a box-shaped chamber 1, and a gas blowing hole 2 and a suction hole 3 are formed in the chamber 1. An air blower is connected to the blowout hole 2 via a pipe line (not shown), and when the air blower is driven based on a command from a control unit (not shown), the gas fed through the pipe is pumped. Is blown out from the blowout hole 2 toward the lower surface 4a of the substrate 4 to float the substrate 4, and an intake blower is connected to the suction hole 3 via a pipe line (not shown), from the control device. When the intake blower is driven based on the command, the suction force acts on the substrate 4 so that the substrate 4 is attracted downward (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-154040 (FIG. 4)

  However, in such a conventional work stage, the pressure inside the suction hole 3 cannot be kept constant. For example, as shown in FIG. When it was conveyed in the direction and gradually covered from the edge of the suction hole 3, the flow rate of the outside air indicated by the arrow B sucked into the suction hole 3 decreased, and the pressure inside the suction hole 3 decreased. Therefore, the differential pressure between the inside of the suction hole 3 and the outside air is increased, and the edge 4b of the substrate 4 passing over the suction hole 3 may be pulled and distorted inside the suction hole 3. Therefore, when such a conventional work stage is used in an exposure apparatus as a stage for supporting the substrate 4 coated with a photosensitive material, the substrate 4 is distorted and the surface is undulated, and uniform exposure is performed. There was a risk of not being able to.

  In view of the above, an object of the present invention is to provide a work stage and an exposure apparatus that can cope with such problems and enable uniform exposure by suppressing the occurrence of distortion on the substrate surface.

To achieve the above object, the workpiece carrier according to the first invention, the upper surface is formed flat, a plurality of sucking the gas from the plurality of outlet holes and external blowing compressed gas to the outside opens into the upper face A substrate support that supports the substrate in a non-contact manner by providing a suction hole, a supply pipe that supplies compressed gas to the plurality of blowing holes of the substrate support, and a gas sucked through the plurality of suction holes of the substrate support A gas pipe having a predetermined thickness between the upper surface of the substrate support and the substrate by blowing out gas to the substrate on the substrate support and sucking the gas. A work stage that floats the substrate, and is provided in the middle of the exhaust pipe, adjusts the exhaust flow rate and allows the introduction of outside air, and controls the opening and closing of the valve to adjust the amount of outside air introduced. And the suction hole A pressure adjustment unit to maintain a differential pressure between the outside pressure parts at a constant pressure, but with a.

With such a configuration, the substrate support is provided by supplying compressed gas through the supply pipe to the blowout hole of the substrate support provided with a plurality of blowout holes and a plurality of suction holes in the upper surface of the flat substrate. A gas is blown out to the upper substrate, the gas is sucked from the suction hole and exhausted by the exhaust pipe, and the opening / closing of a valve provided in the middle of the exhaust pipe is controlled by the pressure adjustment unit to adjust the amount of outside air introduced. And adjusting the exhaust flow rate of the exhaust pipe to maintain the pressure difference between the pressure inside the suction hole and the outside air pressure at a constant pressure, whereby a predetermined thickness is provided between the upper surface of the substrate support and the substrate. A gas layer is generated to float the substrate.

Further, the substrate support body is provided with a sintered body having a plurality of fine pores continuous in the vertical direction inside the box body with the upper part open, with the upper part of the box body closed, The air hole is used as the blowout hole, and a hole penetrating the sintered body in the vertical direction is formed as the suction hole. As a result, a compressed gas is blown out using a plurality of fine pores continuous in the vertical direction of the sintered body provided by closing the upper portion of the box body inside the box body with the upper portion opened, and the sintered body A hole penetrating in the vertical direction is drilled in to suck out external gas as a suction hole.

  Further, the supply pipe is connected to the box, and the exhaust pipe is connected to a suction hole formed in the sintered body. Compressed gas is supplied to the blowout hole by a supply pipe connected to the box, and external gas sucked from the suction hole is exhausted by an exhaust pipe connected to a suction hole formed in the sintered body.

The pressure adjustment unit detects a pressure sensor for detecting the pressure inside the suction hole, storage means for storing a target value of pressure determined by measurement in advance, and outputs of the pressure sensor and external pressure. Comparing with the output of another pressure sensor to find the differential pressure and calculating the deviation from the target value of the storage means, and opening and closing the valve so that the deviation is within a predetermined range And a drive unit that performs. Thereby, the target value of the pressure measured and determined in advance by the storage means is stored, the pressure inside the suction hole is detected by the pressure sensor, and the output of the pressure sensor and the external pressure are detected by the calculation unit After calculating the differential pressure by comparing with the sensor output , calculate the amount of deviation from the target value read from the storage means, and drive the valve to open and close the valve so that the amount of deviation falls within the specified range. Thus , the differential pressure between the pressure inside the suction hole and the outside air pressure is made constant .

An exposure apparatus according to a second aspect of the present invention is provided on a substrate transport path of a substrate that holds both ends of a substrate coated with a photosensitive material and conveys the substrate in a predetermined direction at a constant speed. Provided with a plurality of blowing holes for opening compressed air to the outside by opening on the flat upper surface and a plurality of suction holes for sucking the gas from the outside, and for adjusting the pressure difference between the pressure inside the suction hole and the external pressure a workpiece stage for floating the substrate to generate a gas layer of desired thickness between the substrate that will be conveyed by the upper surface and said transfer means to maintain a constant pressure, is disposed above the work stage, And an exposure optical system for forming a predetermined exposure pattern by irradiating the substrate transported in a non-contact manner with exposure light through a photomask.

With such a configuration, the both ends of the substrate coated with the photosensitive material are held by the transfer means and transferred at a constant speed in a predetermined direction, and are arranged on the transfer path of the substrate of the transfer means and formed flat. The work stage is provided with a plurality of blowout holes that open to the upper surface and blow out compressed gas to the outside, and a plurality of suction holes that suck the gas from the outside, and the differential pressure between the pressure inside the suction hole and the external pressure is made constant maintained by floating the substrate to generate a gas layer of a predetermined thickness between the substrates that will be carried by said upper surface and said conveying means, by applying a photosensitive material to be conveyed on the workpiece in the exposure optical system A predetermined exposure pattern is formed by irradiating the substrate with exposure light through a photomask.

  Furthermore, the work stage is provided with a through-hole penetrating in the vertical direction in a portion corresponding to an exposure light irradiation region by the exposure optical system so that the exposure light transmitted through the substrate passes downward. . The exposure light transmitted through the substrate is released downward through a through hole provided in a vertical direction in a portion corresponding to an exposure light irradiation region by the exposure optical system.

According to the work stage of the first aspect, the differential pressure between the pressure inside the suction hole and the external air pressure can be kept constant even when the substrate passes over the suction hole opened on the upper surface of the substrate support. The edge of the substrate is not pulled inside the suction hole, and the occurrence of distortion of the substrate surface can be suppressed.

Moreover, according to the invention which concerns on Claim 2, the several fine void | hole which continued to the up-down direction which a sintered compact originally has inside can be utilized as a blowing hole. Therefore, gas can be blown uniformly over the entire upper surface of the substrate support. In this case, since the blowout holes are fine, the gas blowout power can be reduced. Therefore, the thickness of the gas layer between the upper surface of the substrate support and the substrate can be easily reduced.

Furthermore, according to the invention which concerns on Claim 3, compressed gas can be supplied uniformly to the several void | hole of a sintered compact. Therefore, gas can be blown uniformly over the entire upper surface of the substrate support.

According to the fourth aspect of the invention, it is possible to automatically adjust so that the differential pressure between the pressure inside the suction hole and the external pressure is maintained at a constant pressure. Therefore, it is easy to adjust the differential pressure between the pressure inside the suction hole and the external pressure in order to suppress the occurrence of distortion of the substrate surface.

According to the exposure apparatus of the fifth aspect, even if the substrate passes over the suction hole opened on the upper surface of the substrate support , the pressure difference between the pressure inside the suction hole and the external pressure can be kept constant. Therefore, the edge of the substrate is not pulled inside the suction hole, and the occurrence of distortion of the substrate surface can be suppressed. Therefore, the photosensitive material applied to the substrate surface can be uniformly exposed. Thereby, an exposure pattern can be formed with high accuracy.

  According to the sixth aspect of the present invention, when the substrate is transparent, the exposure light transmitted through the substrate is diffusely reflected on the upper surface of the work stage and returns to the substrate side to expose portions other than the predetermined region. There is no fear of it. Therefore, the exposure pattern can be formed with higher accuracy.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front view showing an embodiment of an exposure apparatus according to the present invention. This exposure apparatus forms a predetermined exposure pattern by irradiating a substrate coated with a photosensitive substance with exposure light through a photomask. A conveying means 5, a work stage 6, and an exposure optical system 7 are used. It consists of.

The conveying means 5 holds both ends of the substrate 4 coated with a photosensitive material and conveys the substrate 4 at a constant speed in the direction indicated by the arrow A in FIG. It is provided on both sides in the direction orthogonal to the (A direction). A specific example thereof is, for example, a plurality of transport rollers arranged in the transport direction as shown in FIG. In this case, the transport means 5 sinks downward by a predetermined amount due to the weight of the substrate 4 and the suction force by the suction holes 3.

A work stage 6 is provided on the transfer path of the transfer means 5. The work stage 6 is provided with a plurality of blowing holes that open to a flat upper surface 8 and blow out compressed gas to the outside, and a plurality of suction holes that suck the gas from the outside. to maintain the differential pressure at a constant pressure as it levitates the substrate 4 to generate a gas layer 9 having a predetermined thickness between the substrate 4 that will be carried by the upper surface 8 and the conveying means 5, FIG. 1 The substrate 4 can be conveyed in a non-contact manner in the direction of arrow A shown in FIG. Furthermore, a through hole 10 penetrating in the vertical direction is provided in a portion corresponding to an exposure light irradiation region by an exposure optical system 7 to be described later, so that the exposure light transmitted through the substrate 4 can go downward through the through hole 10. I have to. Specifically, as shown in FIG. 2, the unit work stages 11 whose upper surfaces are rectangular are arranged in a quadrangular shape, and the pair of unit work stages 11 are conveyed by the arrow A in the longitudinal direction in the figure. A pair of unit work stages 11 are arranged in parallel to the conveying direction outside the both ends of the pair of unit work stages 11 so as to be orthogonal to each other at a predetermined distance. . Each unit work stage 11 includes a substrate support 12, a supply pipe 13, an exhaust pipe 14, a valve 15, and a pressure adjustment unit 16, as shown in FIG. 3.

The substrate support 12 includes a rectangular parallelepiped sintered body 18 having a plurality of fine pores continuous in the vertical direction inside a rectangular parallelepiped box 17 having an open top. The upper portion of the box body 17 is closed so as to form a portion 17a, and a plurality of holes of the sintered body 18 are used as the blowout holes 2 so as to penetrate the sintered body 18 in the vertical direction. The suction hole 3 is formed by making a hole to be formed. In this case, as shown in FIG. 2, a plurality of suction holes 3 are formed in, for example, three rows along the longitudinal direction of the sintered body 18.

At least one supply pipe 13 is provided on the bottom 17 b of the box 17 of the substrate support 12. The supply pipe 13 supplies compressed gas, for example, clean air, to the plurality of blowout holes 2, one end of which is connected to the hollow portion 17 a of the box body 17, and the other end is an air supply blower (not shown). It is connected to the.

  A single exhaust pipe 14 is connected to the suction hole 3 formed in the sintered body 18 of the substrate support 12. The exhaust pipe 14 exhausts the gas sucked through a large number of suction holes 3, and one end side branches as a branch pipe 14 a in accordance with the number of the suction holes 3, and the respective end parts thereof are suction holes 3. The other end is connected to an intake blower (not shown).

  A valve 15 is provided in the middle of the exhaust pipe 14. The valve 15 is an electromagnetic valve that adjusts the exhaust gas flow rate and allows outside air to be introduced. For example, the valve 15 is an electromagnetic valve that opens and closes in response to an electrical signal.

A pressure adjusting unit 16 is connected to the valve 15 by a signal line L. The pressure adjustment unit 16 controls the valve 15 to adjust the amount of outside air introduced, and maintains the pressure difference between the pressure inside the suction hole 3 and the outside air pressure at a constant pressure. And a memory 20, a calculation unit 21, and a drive unit 22.

  The pressure sensor 19 is provided inside the portion where the branch pipe 14a of the exhaust pipe 14 joins, and detects the internal pressure. The memory 20 stores the best pressure (target value) found by measurement in advance and serves as storage means. Further, the calculation unit 21 compares the output value of the pressure sensor 19 with the output value of a pressure sensor that detects the pressure of outside air provided separately to obtain the differential pressure, and reads the differential pressure from the memory 20. The amount of deviation from the target value is calculated. The drive unit 22 opens and closes the valve 15 so that the deviation from the target value is within a predetermined range (preferably substantially zero) based on the calculation result of the calculation unit 21. The predetermined range is an allowable range of deviation from the target value such that the amount of deflection of the edge 4b of the substrate 4 shown in FIG. 5 falls within the allowable value. It is determined by size and rigidity.

  An exposure optical system 7 is disposed above the work stage 6 as shown in FIG. The exposure optical system 7 forms a predetermined exposure pattern by irradiating exposure light through a photomask 23 onto a substrate 4 coated with a photosensitive material conveyed on the upper surface 8 of the work stage 6. A light source 24, a mask stage 25, and a condenser lens 26.

  The light source 24 emits exposure light including ultraviolet rays, and is, for example, an ultrahigh pressure mercury lamp, a xenon lamp, an ultraviolet laser oscillator, or the like. Further, the mask stage 25 is disposed in the vicinity of the upper surface 8 of the work stage 6. The mask stage 25 holds the strip-shaped photomask 23 in a plane parallel to the upper surface 8 so that the longitudinal direction thereof is orthogonal to the transport direction (arrow A direction). The photomask 23 is formed with a plurality of mask patterns 27 arranged along the longitudinal direction. Further, a condenser lens 26 is disposed between the light source 24 and the mask stage 25. The condenser lens 26 is used to vertically irradiate the exposure light emitted from the light source 24 onto the photomask 23 held on the mask stage 25, and the focal position thereof is a condensing point of the light source 24. It is located in the vicinity.

Next, the operation of the exposure apparatus configured as described above will be described.
First, the transport means 5 is activated, and the substrate 4 having a photosensitive material coated on the surface is held by the transport means 5 and transported in the direction of arrow A shown in FIG. At this time, for example, clean air of compressed gas supplied through the supply pipe 13 is blown out from the blow hole 2 of the work stage 6 shown in FIG. 3 onto the upper surface 8, and gas is sucked from the suction hole 3. Yes.

  When the substrate 4 transported by the transport means 5 reaches the upper surface 8 of the work stage 6, the compressed gas blown from the blowout holes 2 is blown onto the lower surface 4 a of the substrate 4, so that the substrate 4 is placed on the upper surface 8 of the work stage 6. Surface. On the other hand, since the blown-out gas is sucked from the suction hole 3, the substrate 4 that has floated is attracted to the upper surface 8 side of the work stage 6. At this time, if the gas suction by the suction hole 3 is adjusted to be stronger than the gas blown from the blow hole 2, a thin gas layer 9 is formed between the lower surface 4 a of the substrate 4 and the upper surface 8 of the work stage 6. As a result, the substrate 4 floats and is transported on the work stage 6 in a non-contact manner.

  In this case, the edge 4 b of the substrate 4 gradually covers the suction hole 3 on the upper surface 8 of the work stage 6 as the substrate 4 moves. At the same time, the outside air sucked into the suction hole 3 indicated by the arrow B in FIG. 3 decreases, and the pressure inside the suction hole 3 decreases.

At this time, as shown in FIG. 3, the pressure drop in the suction hole 3 is detected by the pressure sensor 19 of the pressure adjustment unit 16, and the output is sent to the calculation unit 21. The calculation unit 21 compares the input pressure signal with the value of a pressure sensor that detects the external air pressure provided separately to obtain the differential pressure between the pressure inside the suction hole 3 and the external air pressure, and is measured in advance and stored in the memory. The target value of the pressure stored in 20 is read and compared. Then, the drive unit 22 is driven to open the valve 15 so that the amount of deviation from the target value is within a predetermined range (preferably substantially zero), and the outside air is exhausted from the exhaust pipe as indicated by an arrow C in FIG. 14 and the exhaust flow rate is made constant. As a result, the pressure inside the junction part of the branch pipe 14a of the exhaust pipe 14, that is, the pressure inside the suction hole 3 becomes constant, the differential pressure between the inside of the suction hole 3 and the outside air is kept constant, and the edge 4b of the substrate 4 is sucked. The amount of distortion caused by being pulled inside the hole 3 is in an allowable range. Therefore, the surface of the substrate 4 is kept uniform or substantially uniform.

Next, the exposure light is emitted from the light source 24 shown in FIG. 1, the exposure light is irradiated vertically to the photomask 23 held on the mask stage 25 is collimated by the condenser lens 26. Further, the exposure light passing through the photomask 23 is irradiated vertically onto the substrate 4 to be transported on the upper surface 8 of the workpiece stage 6 in the direction of arrow A shown in FIG. As a result, the mask pattern 27 formed on the photomask 23 is transferred to the photosensitive material applied to the surface of the substrate 4. In this case, the exposure light transmitted through the substrate 4 passes through a through hole 10 provided on the work stage 6 in the vertical direction downward. Therefore, the exposure light that has passed through the substrate 4 is not diffusely reflected, for example, at the edge of the suction hole 3 on the upper surface 8 and returned to the substrate 4 side, so that a portion different from the predetermined region is not exposed. If a light absorber is provided below the through hole 10, the exposure light transmitted through the substrate 4 can be absorbed and removed.

  In the above description, although the case where the through hole 10 is provided in the work stage 6 has been described, the present invention is not limited thereto, and the through hole 10 may not be provided. Further, the conveying means 5 is not limited to the one in which the conveying rollers are arranged, and any means may be used as long as it can convey while holding both ends of the substrate. Furthermore, the work stage 6 is not limited to that used in the exposure apparatus.

It is a front view which shows embodiment of the exposure apparatus by this invention. It is a top view which shows the principal part of the said exposure apparatus. It is explanatory drawing of the work stage shown in the cross section of XX in FIG. It is sectional drawing which shows the principal part of the conventional work stage. It is explanatory drawing which shows the state which the edge of the board | substrate was distorted in the conventional work stage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Outlet 3 ... Suction hole 4 ... Substrate 5 ... Conveying means 6 ... Work stage 7 ... Exposure optical system 8 ... Upper surface 9 ... Gas layer 10 ... Through-hole 11 ... Unit work stage 12 ... Substrate support 13 ... Supply pipe 14 ... exhaust pipe 15 ... valve 16 ... pressure adjusting unit 17 ... box 17a ... hollow part 18 ... sintered body 19 ... pressure sensor 20 ... memory (memory means)
21 ... Calculation unit 22 ... Drive unit 23 ... Photomask

Claims (6)

A substrate support that has a flat upper surface and is provided with a plurality of blowing holes that open to the upper surface and blow compressed gas to the outside and a plurality of suction holes that suck the gas from the outside to support the substrate in a non-contact manner;
A supply pipe for supplying compressed gas to the plurality of blowout holes of the substrate support;
An exhaust pipe for exhausting the gas sucked through the plurality of suction holes of the substrate support;
A workpiece that blows out gas to the substrate on the substrate support and sucks the gas to generate a gas layer having a predetermined thickness between the upper surface of the substrate support and the substrate to float the substrate Stage,
A valve provided in the middle of the exhaust pipe to adjust the exhaust flow rate and to introduce outside air;
A pressure adjusting unit that controls the opening and closing of the valve to adjust the introduction amount of outside air, and maintains a differential pressure between the pressure inside the suction hole and the outside pressure at a constant pressure;
Work stage characterized by having The substrate support is provided with a sintered body having a plurality of fine vacancies continuous in the vertical direction inside the box with the upper portion open, with the upper portion of the box closed, and the voids of the sinter 2. The work stage according to claim 1, wherein the suction hole is formed as a suction hole by forming a hole penetrating in the vertical direction in the sintered body.   3. The work stage according to claim 2, wherein the supply pipe is connected to the box and the exhaust pipe is connected to a suction hole formed in the sintered body. The pressure adjustment unit includes a pressure sensor that detects a pressure inside the suction hole, a storage unit that stores a target value of a pressure determined by measurement in advance, and another output that detects an output and an external pressure of the pressure sensor . A calculation unit that compares the output of the pressure sensor to obtain a differential pressure and calculates a deviation amount from the target value of the storage means, and a drive that opens and closes the valve so that the deviation amount falls within a predetermined range The work stage according to any one of claims 1 to 3, wherein the work stage is composed of a part. Conveying means for holding both ends of the substrate coated with the photosensitive material and conveying the substrate in a predetermined direction at a constant speed;
The suction means is provided on a transport path of the substrate of the transport means, and is provided with a plurality of blowing holes that open on a flatly formed upper surface and blow compressed gas to the outside and a plurality of suction holes that suck the gas from the outside. work stage to float the substrate to generate a gas layer of a predetermined thickness between the substrates to maintain the pressure difference between the hole interior of the pressure and the external atmospheric pressure at a constant pressure Ru is conveyed by the upper surface to the conveying means When,
An exposure optical system which is disposed above the work stage and forms a predetermined exposure pattern by irradiating exposure light through a photomask to the substrate which is conveyed in a non-contact manner on the work stage;
An exposure apparatus comprising:   The work stage is provided with a through-hole penetrating in a vertical direction in a portion corresponding to an exposure light irradiation region by the exposure optical system, so that the exposure light transmitted through the substrate passes downward through the through-hole. 6. An exposure apparatus according to claim 5, wherein:

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