JP4978632B2 - Exposure equipment - Google Patents

Description

The present invention relates to a dew HikariSo location.

  When exposing a substrate such as a color filter, a technique is known in which nitrogen is jetted onto the substrate surface and the surface is purged with nitrogen. By purging with nitrogen, reaction inhibition of the resist surface by oxygen is prevented, and the exposure time is shortened.

  However, the above-described technique has not improved the production efficiency so much. For example, there is a limit to the pressure at which nitrogen is ejected from the viewpoint of preventing photomask displacement, and it is necessary to gradually replace oxygen with nitrogen at a low pressure. For this reason, a long time was required for the nitrogen purge. Therefore, even if the exposure time is shortened by performing the nitrogen purge, the time required for the nitrogen purge is added, so that the time for the entire exposure process for the substrate has not been shortened much. A method of replacing the entire chamber of the exposure apparatus with nitrogen is also conceivable, but a large amount of nitrogen gas is necessary and not practical.

  Accordingly, an object of the present invention is to provide an exposure method and an exposure apparatus that can improve the production efficiency by purging the substrate surface with an inert gas.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

According to the first aspect of the present invention, the photomask and the substrate (200) are synchronously scanned with the light transmitted through the slit from above the photomask (65) to project the pattern of the photomask into the projection optical system (66). In the exposure apparatus (60) that exposes the substrate via (), a slit formed in an arc shape so as to correspond to the shape and size of the arc-shaped projection image (i) projected onto the substrate by the projection optical system A plate material (70) provided with a nozzle (76) having a shape, a transparent film (73) provided on the plate material so as to close the opening on the projection optical system side of the nozzle, and the nozzle Gas supply means (64) for supplying an inert gas, and the plate member is disposed between the projection optical system and the substrate so that a light beam from the projection optical system passes through the nozzle. ing And it allows to solve the problems described above.

In a scanning exposure apparatus such as a mirror projection system or a lens projection system, exposure is performed by scanning an arc-shaped or linear projection image on a substrate. According to the first aspect of the present invention, the strip-shaped optical image passes through the film and is exposed, while the slit-shaped nozzle ejects the inert gas toward the strip-shaped projection image. Therefore, purging is performed simultaneously with the progress of exposure, and the time required for purging is omitted. Further, since the inert gas is ejected only in the projected image, the inert gas necessary for purging is reduced as compared with the case where the entire chamber is purged with the inert gas.

In the invention of claim 1, the plate member is disposed so as to face the gap between the film and the substrate, and the side walls (71 a, 72 b) that form the nozzles are open to the side wall and A gas flow path (75) connected to the gas supply means may be provided.

As described above, according to the exposure apparatus of the present invention, the strip-shaped optical image is transmitted through the film and the exposure is performed, while the slit-shaped nozzle ejects the inert gas toward the strip-shaped projection image. Is done. Therefore, purging is performed simultaneously with the progress of exposure, and the time required for purging is omitted. Further, since the inert gas is ejected only in the projected image, the inert gas necessary for purging is reduced as compared with the case where the entire chamber is purged with the inert gas.

The side view which shows the structure of the exposure apparatus which concerns on the reference example of this invention. The top view which shows the stage and mask holder of the exposure apparatus of FIG. Sectional drawing and a top view which show a part of mask holder of the exposure apparatus of FIG. The side view which shows the measuring device of the exposure apparatus of FIG. 3 is a flowchart showing a procedure of exposure processing executed by the control device of the exposure apparatus in FIG. 1. 6 is a flowchart showing a procedure of gap adjustment processing executed by the control device of the exposure apparatus in FIG. 1. FIG. 6 is a side view showing a state on the stage when the exposure process of FIG. 5 is being executed. Side view showing the configuration of an exposure apparatus according to implementation embodiments of the present invention. FIG. 9 is a cross-sectional view showing a nitrogen blowing portion of the exposure apparatus in FIG. 8.

( Reference example )
FIG. 1 is a side view showing a configuration of an exposure apparatus 1 according to a reference example of the present invention. The exposure apparatus 1 is configured as an apparatus that performs proximity-type exposure on the color filter substrate 100.

  The substrate 100 is composed of, for example, a glass substrate, and a photosensitive resin or a resist (negative type) in which a pigment is dispersed is formed in a thin film on the surface of the glass substrate. The substrate 100 is formed with a thickness of 1 mm and an area of 4 m2, for example. Six color filters are taken out from one substrate 100. Therefore, as shown in FIG. 2A, the exposure apparatus 1 exposes the six exposure regions 100a... 100a on the substrate 100.

  An exposure apparatus 1 in FIG. 1 includes a stage 2 on which a substrate 100 is placed, a driving device 3 that drives the stage 2 in the horizontal direction, an exposure optical system 50 that includes a photomask 4, and a mask holder that holds the photomask 4. 5, a driving device 6 that drives the mask holder 5 in the vertical direction, an air supply / exhaust device 7 (gas supply means) that supplies air to the mask holder 5 and exhausts air from the mask holder 5, and nitrogen in the mask holder 5 Nitrogen supply device 8 (gas supply means), measuring devices 9 ... 9 (specifying means) for measuring the height of the surface of the substrate 100, and a control device 10. In addition, the exposure apparatus 1 further includes various apparatuses such as an illumination apparatus that irradiates a light beam from above the photomask 4 toward the substrate 100 and a laser length measuring instrument that measures the horizontal position of the stage 2. However, since it is not the gist of the present invention, explanation is omitted.

  The driving device 3 and the driving device 6 are configured as electric motors, for example. The air supply / exhaust device 7 includes a pressurization / decompression line and a pressure adjustment valve, and can send out nitrogen at a desired pressure from a nitrogen tank (not shown). The nitrogen supply device 8 includes, for example, a pressure adjusting valve, and can send out nitrogen at a desired pressure from a pressurized nitrogen tank (not shown). The control device 10 is configured as a computer including, for example, a CPU, a ROM, a RAM, and an external storage device, and according to a program recorded in the external storage device, the drive device 3, the drive device 6, the air supply / exhaust device 7, and the nitrogen supply Control the operation of the device 8 and the like.

  As shown in FIG. 2A, the outer periphery of the stage 2 extends over one of the four sides (edges) of the substrate 100, which becomes the top when moving below the photomask 4, A slit-like nozzle 30 opening on the stage 2 is provided. Further, as shown in FIG. 7A, the stage 2 is provided with a gas flow path 31 provided along the nozzle 30 and opening to the nozzle 30. The gas flow path 31 is connected to the nitrogen supply measure 8. According to this, when the substrate 100 is moved under the photomask 4, oxygen contained in the atmosphere on the outer periphery of the substrate 100 can be prevented from being drawn into the gap due to frictional resistance with the photomask 4.

  As shown in FIG. 2A, the photomask 4 has a size that covers one exposure region 100a. The optical image of the photomask 4 is projected onto the exposure area 100a. As shown in FIG. 2B, the mask holder 5 is formed in a frame shape and holds the outer peripheral side of the photomask 4. The mask holder 5 includes an inner frame portion 5a and an outer frame portion 5b.

  3A is a sectional view showing the inner frame portion 5a, and FIG. 3B is a plan view of the inner frame portion 5a as viewed from below. The inner frame portion 5 a includes a lower step portion 11 and an upper step portion 12.

  The lower step portion 11 is formed in an inverted L-shaped cross section and is provided so as to surround the photomask 4. The lower part 11 includes a suction groove 18 for holding the photomask 4. The suction groove 18 is provided inside the lower surface of the horizontal portion 11 a of the lower step portion 11. The photomask 4 is sucked and fixed to the lower stage portion 11 by performing air bleeding between the photomask 4 and the lower surface of the horizontal portion 11a through a suction groove 18 by a vacuum pump (not shown).

  The lower portion 11 includes a nozzle 13 that opens downward, and a gas flow path 14 that opens to the nozzle 13. The nozzle 13 is formed by providing a gap between the inner wall 11 c of the lower step portion 11 and the side wall 4 b of the photomask 4, and is a slit-like nozzle surrounding the photomask 4. The gas flow path 14 is provided along the outer periphery of the nozzle 13. The gas flow path 14 may continuously open to the nozzle 13 over the entire circumference, or may intermittently open to the nozzle 13. The gas flow path 14 is connected to the air supply / exhaust device 7. Further, an air dam 15 protruding downward is provided on the outer peripheral side (inner wall 11 c) of the nozzle 13. The air dam 15 protrudes several tens of μm below the lower surface 4 d of the photomask 4.

  The upper step portion 12 is formed in an inverted L shape in cross section and is provided so as to surround the lower step portion 11. The upper stage portion 12 includes a nozzle 16 that opens downward, and a gas flow path 17 that opens to the nozzle 16. The nozzle 16 is formed by providing a gap between the inner wall 12 a of the upper step portion 12 and the outer wall 11 d of the lower step portion 11, and is a slit-like nozzle surrounding the lower step portion 11. The lower end of the outer peripheral side (inner wall 12a) of the nozzle 16 is higher than the lower end of the inner peripheral side (outer wall 11d). The gas flow path 17 is provided along the outer periphery of the nozzle 16. The gas channel 17 may continuously open to the nozzle 16 over the entire circumference, or may intermittently open to the nozzle 16. The gas flow path 17 is connected to the nitrogen supply device 8.

  As shown in FIG. 2 (b), the outer frame portion 5b is held at three points by holders 6a ... 6a. The driving device 6 can independently drive the holders 6a... 6a up and down, and can adjust the vertical position and inclination of the mask holder 5. Moreover, measuring devices 9 ... 9 are provided in the outer frame portion 5b. The number and mounting positions of the measuring devices 9 ... 9 may be set as appropriate.

  As shown in FIG. 4, the measuring device 9 includes a light emitting unit 21 and a sensor 22. The light emitting unit 21 includes, for example, a light emitting diode, and is set to emit light toward the substrate 100 at a predetermined angle. The sensor 22 includes, for example, a semiconductor element. When the sensor 22 receives light on the detection surface 22a, the sensor 22 outputs a signal corresponding to the light receiving position to the control device 10. The positions of the light emitting unit 21 and the sensor 22 are such that, for example, when the substrate 100 and the photomask 4 are opposed to each other through a proximity gap, the light of the light emitting unit 21 reflected by the substrate 100 reaches the center of the detection surface 22a. It is set to be. Therefore, the control device 10 can specify the height of the substrate 100 based on the signal from the sensor 22 based on the principle of triangulation.

  The operation of the exposure apparatus 1 having the above configuration will be described below.

  FIG. 5 is a flowchart showing the procedure of exposure processing executed by the control device 10. This process is started, for example, when the substrate 100 is placed on the stage 2. The substrate 100 is placed on the stage 2 when the stage 2 is waiting outside the photomask 4.

  When the substrate 100 is placed on the stage 2, the control device 10 controls the operation of the driving device 3 to move the stage 2 until just before the top of the substrate 100 enters below the photomask 4 (step S1). ). As shown in FIG. 7A, when the top of the substrate 100 reaches a position immediately before entering the lower side of the photomask 4, the control device 10 drives the air supply / exhaust device 7 and the nitrogen supply device 8, and the nozzle 13, Nitrogen ejection from the nozzle 16 and the nozzle 30 is started (step S2). Moreover, the control apparatus 10 specifies the height of the surface of the board | substrate 100 based on the signal from measuring device 9 ... 9 (step S3). Next, based on the specified height, the operation of the driving device 6 is performed so that the difference in height between the photomask 4 and the substrate 100 becomes a proximity gap (see symbol P in FIG. 1, for example, 100 μm). Is controlled to move the photomask 4 up and down (step S4).

  When the difference in height between the photomask 4 and the substrate 100 is set to the proximity gap, the control device 10 moves the stage 2 to the first exposure position (step S5). At this time, as shown in FIG. 7B, nitrogen blown from the nozzles 13 and 16 at the position where the substrate 100 enters (the right side of the photomask 4 in the figure) and the nozzle 30 flows into the photomask 4 and the substrate. It flows in the direction of low pressure while blocking the gap between the two and the outside from the outside. The direction in which the jetted pressure flows depends on the jet pressure from each nozzle, the distance between the nozzles, the gap amount between the substrate 100 and the photomask 4, etc. When the pressure is set to be larger than the pressure of the nozzle, as shown in FIG. 7B, the nitrogen ejected from the nozzle 13 is mainly produced by the movement of the stage 2 indicated by the arrow y1. The gas flows below the mask 4 and fills the gap between the photomask 4 and the substrate 100 with nitrogen, and the nitrogen blown from the nozzle 16 and the nozzle 30 mainly moves outside the gap between the substrate 100 and the photomask 4. The oxygen flowing around the photomask 4 is removed. When the exposure region 100a is positioned below the photomask 4, the gap between the photomask 4 and the substrate 100 is filled with nitrogen as shown in FIG. 7C.

  In step S <b> 6, the control device 10 drives a light source (not shown) to expose the exposure region 100 a aligned with the photomask 4. Note that the control device 10 ejects nitrogen from the nozzle 13, the nozzle 16, and the nozzle 30 at an appropriate pressure even during exposure. In step S7, it is determined whether or not the exposure has been completed for all the exposure areas 100a... 100a. If it is determined that the exposure has not been completed, steps S5 and S6 are repeated, and the remaining exposure areas 100a. The exposure is performed sequentially. When the stage 2 is moved so as to align the photomask 4 with the remaining exposure areas 100a... 100a, the nozzle 13 at the position where the next exposure area 100a enters as in FIG. The nitrogen blown out from below flows below the photomask 4 as the stage 2 moves. If it is determined in step S7 that the exposure has been completed for all the exposure regions 100a ... 100a, the flow rate is such that oxygen does not enter the nozzles by backflow of nitrogen from the nozzles 13, 16 and 30. Then, the process ends.

  FIG. 6 is a flowchart illustrating the procedure of the gap adjustment process executed by the control device 10. This process is repeatedly executed at a predetermined cycle (for example, 0.1 second) while the stage 2 is moved under the photomask 4 (step S5 in FIG. 5).

  In step S11, the control device 10 specifies the height of the surface of the substrate 100 based on signals from the measuring devices 9. Next, based on the specified height, the photomask 4 is moved up and down by controlling the operation of the driving device 6 so that the gap amount between the photomask 4 and the substrate 100 is maintained in the proximity gap. (Step S12). Steps S11 and S12 are repeatedly executed, and closed loop control is executed.

  In steps S5 and S6, the control device 10 controls the air supply / exhaust device 7 so that the pressure in the gap between the photomask 4 and the substrate 100 becomes a static pressure that can correct the bending deformation of the photomask 4. Nitrogen is ejected from the nozzle 13 and the gap is exhausted through the nozzle 13 as necessary. For example, the control device 10 controls the air supply / exhaust device 7 so that the pressure in the gap between the photomask 4 and the substrate 100 becomes a pressure represented by the following equation.

上式では、フォトマスク４の材質比重（比重量）ρにフォトマスク４の厚さｔを乗算してフォトマスク４の単位面積あたりの重さを求め、そのフォトマスク４の単位面積あたりの重さと大気圧とを足し合わせた圧力を間隙の圧力の適正値としている。適正値において、間隙の気体がフォトマスク４を押し上げる力は、大気圧とフォトマスク４の重さによりフォトマスク４に対して下方へ働く力と同じになる。従って、フォトマスク４に働く力がキャンセルされて、自重による撓み変形が適切に矯正される。間隙の圧力が上式の適正値以下であると、フォトマスク４の変形を十分に矯正することができず、以上となると、間隙の圧力が増大しすぎてマスクが凸状に変形する。なお、フォトマスク４の平坦度が重力ベンドを矯正しても凸又は凹である事が判れば間隙の圧力を更に補正して精度を向上できる。

In the above equation, the material specific gravity (specific weight) ρ of the photomask 4 is multiplied by the thickness t of the photomask 4 to obtain the weight per unit area of the photomask 4, and the weight per unit area of the photomask 4 is calculated. The sum of the pressure and the atmospheric pressure is taken as the appropriate value for the pressure in the gap. At an appropriate value, the force with which the gas in the gap pushes up the photomask 4 is the same as the force acting downward on the photomask 4 due to the atmospheric pressure and the weight of the photomask 4. Accordingly, the force acting on the photomask 4 is canceled and the bending deformation due to its own weight is appropriately corrected. If the pressure in the gap is less than or equal to the appropriate value of the above equation, the deformation of the photomask 4 cannot be sufficiently corrected. If the pressure is above, the pressure in the gap increases too much and the mask is deformed into a convex shape. If it is found that the flatness of the photomask 4 is convex or concave even when the gravity bend is corrected, the accuracy of the gap can be further corrected by improving the gap pressure.

  In order to keep the pressure in the gap between the substrate 100 and the photomask 4 at the above-described pressure, the control device 10 may perform various controls on the air supply / exhaust device 7. For example, the operation of the air supply / exhaust device 7 may be controlled so that nitrogen is fed from the nozzle 13 at the above pressure. The pressure in the gap may be maintained at the above-mentioned pressure by monitoring the pressure in the gap and performing feedback control on the air supply / exhaust device 7 based on the monitoring result. An operation pattern of the air supply / exhaust device 7 in which the pressure of the gap quickly converges to the pressure of the above formula may be obtained in advance by experiments or the like, and the air supply / exhaust device 7 may be controlled to perform the operation. Since the upper part of the gap between the photomask 4 and the substrate 100 is surrounded by the air dam 15, gas is easily held in the gap. Therefore, it is easy to keep the gap pressure constant.

  The ejection pressure from the nozzle 16 and the nozzle 30 may be set as appropriate. However, it is desirable that the flow rate be such that the oxygen on the surface can be replaced with nitrogen at a pressure that does not affect the correction of the deflection of the photomask 4 due to supply and exhaust through the nozzle 13. In addition, since the lower end of the outer peripheral side (inner wall 12a) of the nozzle 16 is higher than the lower end of the inner peripheral side (outer wall 11d), nitrogen flows to the outer peripheral side even when nitrogen is blown out at a relatively high pressure. The effect on deflection correction is reduced.

(Implementation form)
Figure 8 is a diagram showing an exposure apparatus 60 according to the implementation embodiments of the present invention. The exposure apparatus 60 is configured as a projection exposure apparatus that scans and exposes an arc-shaped projection image on the color filter substrate 200.

  Similarly to the substrate 100, the substrate 200 is formed of, for example, a glass substrate, and a photosensitive resin or a resist (negative type) in which a pigment is dispersed is formed in a thin film on the surface of the glass substrate.

  The exposure apparatus 60 supplies nitrogen to a stage 61 on which the substrate 200 is placed, a driving device 62 that drives the stage 61 in the horizontal direction, a nitrogen ejection part 63 disposed on the substrate 200, and a nitrogen ejection part 63. A nitrogen supply device 64, an exposure optical system 67 including a photomask 65 and a projection optical system 66, a drive device 68 for driving the photomask 65 in the horizontal direction, and a control device 69 are provided. In addition, the exposure device 60 includes various devices such as an illumination device that irradiates the transmitted light of the slit from above the photomask 65, and a laser length measuring device that measures the horizontal position of the stage 61. Since it is not the gist of the present invention, the description is omitted.

The driving device 62 and the driving device 68 are configured to include, for example, an electric motor, and the stage 61 or the photomask 65 of FIG. 8 is arranged so that the arc-shaped projection image of the light beam L is scanned over the entire substrate 200 or the photomask 65. It can be driven in the left-right direction. The configuration of the nitrogen supply device 64 and the control device 69 is substantially the same as the configuration of the nitrogen supply device 8 and the control device 10 according to the reference example . The projection optical system 66 may be, for example, a mirror projection optical system combining a trapezoidal reflecting mirror, a convex mirror, and a concave mirror, or a lens projection optical system including a plurality of lens groups.

  The nitrogen blowing portion 63 includes a plate member 70 having an arc-shaped hole, and a pellicle 73 stretched on the upper surface of the plate member 70. The plate member 70 has an outer shape formed in an arc shape, and includes frame portions 71 and 72 that extend in an arc shape, and end portions 74 and 74 that close both ends thereof. As shown also in FIG. 9, the frame portion 72 includes a gas flow path 75 extending along the frame portion 72. The gas flow path 75 opens to the side wall 72 a of the frame portion 72 and is connected to the nitrogen supply device 64. Side walls 71 a and 72 a facing each other of the frame portion 71 and the frame portion 72 form a slit-like nozzle 76 that opens on the substrate 200. The pellicle 73 is a permeable film, and may be formed using, for example, cellulose. The nitrogen ejection part 63 is arranged so that the light beam L from the projection optical system 66 passes through the nozzle 76.

  The operation of the exposure apparatus 60 having the above configuration will be described.

  When the substrate 200 is placed on the stage 61, the control device 69 drives the nitrogen supply device 64 so as to eject nitrogen onto the substrate 200 via the nitrogen ejection unit 63. Next, the driving devices 62 and 68 operate so as to drive a light source (not shown) to irradiate the photomask 65 with the light beam L and to scan the photomask 65 and the substrate 200 synchronously with respect to the projection optical system 66. To control. As a result, as shown in FIG. 9, while the substrate 200 is sequentially exposed by the linear projection image i, nitrogen is always blown to the projection image i of the substrate 200 to prevent resist reaction inhibition. The

DESCRIPTION OF SYMBOLS 1,60 Exposure apparatus 3,6,62,68 Drive apparatus 4,65 Photomask 7 Supply / exhaust apparatus 8,64 Nitrogen supply apparatus 9 Measurement apparatus 10,69 Control apparatus 13,16,30,76 Nozzle 66 Projection optical system 100 200 substrates

Claims (2)

In an exposure apparatus that scans the photomask and the substrate synchronously while irradiating light transmitted through the slit from above the photomask, and exposes the photomask pattern onto the substrate via a projection optical system.
A plate material provided with slit-shaped nozzles formed in an arc shape so as to correspond to the shape and size of an arc-shaped projection image projected onto the substrate by the projection optical system, and the projection optical system side of the nozzle A permeable film provided on the plate so as to close the opening, and a gas supply means for supplying an inert gas through the nozzle,
The exposure apparatus according to claim 1, wherein the plate member is disposed between the projection optical system and the substrate so that a light beam from the projection optical system passes through the nozzle . In the plate material, a side wall that is disposed so as to sandwich the gap between the film and the substrate to form the nozzle, a gas flow path that opens to the side wall and is connected to the gas supply unit, The exposure apparatus according to claim 1, wherein each is provided .

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