JP4258620B2 - Substrate processing method by sandblasting - Google Patents

Description

【００３６】
なお、加工前０．９ｍｍの面取り巾は、加工後は表面を０．１ｍｍ除去しているため、面取り部分が選択的に除去されないときは０．８ｍｍとなる。このため０．８ｍｍの場合は、面取り巾変化量は０と表記し、＋は面取り巾が０．８ｍｍより大きくなったことを示している。
【００３７】
【発明の効果】
本発明により、基板表面と面取り面との稜線部分の局部摩耗がなくなり、これにより露光時の基板吸着でのバキュームリーク発生の危険性を防止でき、露光時の吸着不良をなくすことができる。
【図面の簡単な説明】
【図１】基板と板材の配置を示し、（Ａ）は平面図、（Ｂ）は断面図である。
【図２】稜線付近の基板表面の除去が進まないことによる盛り上がり現象を示す一部省略断面図である。
【図３】加工装置の概要を示す斜視図である。
【図４】サンドブラストにおける移動態様を示す斜視図である。
【符号の説明】
１ 基板
２ 板材
３ 面取り面
４ 稜線部
１０ 盛り上がり部分
２０ 基板保持台
２１ サンドブラストノズル
２２ 砥粒の気流[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing method for sandblasting a synthetic quartz substrate, particularly a synthetic quartz substrate for a photomask, a substrate used for a TFT liquid crystal panel, and the like.
[0002]
[Prior art]
In general, in a TFT liquid crystal panel, there is an active method in which liquid crystal is sealed between an array side substrate in which TFT elements are incorporated and a substrate on which a color filter is mounted, and the voltage is controlled by the TFT to control the alignment of the liquid crystal. It is taken.
[0003]
In this case, at the time of manufacturing on the array side, a method is employed in which a master plate on which a circuit called a large photomask is written is baked on a non-alkali mother glass by light exposure. On the other hand, the color filter side is also manufactured by a method using lithography called a dye impregnation method. A large-sized photomask (Non-patent Document 1: “The story of photomask technology”, pages 151 to 158, Industrial Research Co., Ltd., August 20, 1996) is required for manufacturing both the array side and the color filter side. In order to perform accurate exposure, synthetic quartz glass having a small linear expansion coefficient is mainly used as a material for these large photomasks.
[0004]
On the other hand, when processing a substrate using sandblasting, the processing characteristics of sandblasting are that the ridgeline part between the surface and the chamfered surface is easily removed, and when the amount of sandblast removal is large, the ridgeline part is processed and removed greatly There is. Due to this phenomenon, the chamfering width may be different on each side of the substrate, or the chamfering width may be partially increased, which rarely occurs after the polishing process in the subsequent process. Thus, the appearance of the product may be impaired, and in the worst case, a practical problem may occur. Here, the practical problem is that in the normal exposure apparatus, the outer peripheral portion of the substrate surface is vacuum-sucked at the time of exposure, and the substrate is fixed, but when the chamfered ridge line portion is cut too much inside, It means that it cannot leak and adsorb.
[0005]
In order to solve such problems, there is a method of performing sand blasting before chamfering and then chamfering, but the substrate that is not chamfered has a problem that the edge part is weak against impact and has a high probability of being cracked or applied. is there. In addition, a method called so-called thread chamfering, in which after chamfering a little to prevent cracking and chipping, sandblasting and chamfering again, can be considered, but the process becomes long and economically disadvantageous. . Furthermore, in order to prevent the chamfered portion from being worn, there is a method of coating the chamfered portion with a curable resin or the like, but this requires an operation of peeling the resin after processing, which is economically disadvantageous.
[0006]
[Non-Patent Document 1]
“The story of photomask technology”, pages 151-158, Industrial Research Institute, Inc., August 20, 1996 [0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and in particular, when a chamfered substrate is processed by sandblasting, local wear of the ridge line portion between the substrate surface and the chamfered surface is prevented, and a change in the chamfered shape is prevented. An object is to provide a substrate processing method.
[0008]
Means for Solving the Problem and Embodiment of the Invention
As a result of intensive studies to achieve the above-mentioned object, the present inventors have arranged a plate material around the substrate when processing a substrate surface that has been particularly chamfered using sandblasting. By providing it higher, the air flow is changed, the shape change of the chamfered part is prevented, the local wear of the ridge line part between the substrate surface and the chamfered surface is eliminated, and the present invention has been made. is there.
[0009]
Accordingly, the present invention provides the following substrate processing method.
Claim 1:
When sandblasting a synthetic quartz substrate having a chamfered peripheral part, a plate material is disposed on the peripheral part of the substrate in contact with or in proximity to the surface of the substrate so as to protrude 5 to 15 mm from the substrate surface to the blast nozzle side. A substrate processing method comprising sandblasting a surface.
Claim 2 :
Substrate, the substrate processing method according to claim 1, characterized in that the synthetic quartz substrates for photomasks.
Claim 3 :
The substrate processing method according to claim 1 or 2, wherein the substrate has a diagonal length of 500 mm or more and a thickness of 5 to 20 mm.
Claim 4 :
The substrate processing method according to any one of claims 1 to 3, wherein the chamfer width is 0.3 to 1.5 mm.
Claim 5 :
The substrate processing method according to any one of claims 1 to 4, wherein an air pressure of the sandblast is 0.05 to 0.15 MPa and an abrasive grain size is # 600 to # 3000.
[0010]
Hereinafter, the present invention will be described in more detail.
The substrate processing method of the present invention is particularly applied to a large synthetic quartz glass substrate, and is preferable as a photomask substrate, a TFT liquid crystal array side substrate, or the like. The size is such that the diagonal length is 500 mm or more, preferably 500 to 2,000 mm. The shape of the substrate may be a square, a rectangle, a circle, or the like. In the case of a circle, the diagonal length means a diameter. The thickness of the substrate is not limited, but is preferably 1 to 20 mm, particularly 5 to 12 mm.
[0011]
In this case, a substrate whose peripheral portion is chamfered is effectively used as the substrate. The chamfering width is not particularly limited, but is preferably 0.3 to 1.5 mm.
[0012]
In the present invention, the surface of the substrate is sandblasted. In the present invention, as shown in FIG. 1, the entire surface of the peripheral portion of the substrate 1 to be sandblasted is surrounded by the substrate. The board | plate material 2 is arrange | positioned in contact or proximity | contact. In this case, the height of the plate material 2 is higher than the height (thickness) of the substrate 1, and the substrate 1 is sandblasted with the plate material 2 protruding from the surface of the substrate 1 toward the sandblast nozzle (not shown) arrangement side. To do.
[0013]
That is, the present inventor, for example, encloses a substrate having a chamfering width of 45 °, 0.9 mm, and a thickness of 9 mm with a 5 mm-thick plate-shaped resin, and performs an air pressure of 0.1 MPa and a blast material FO # 1000 by sandblasting. As a result of 100μm removal processing near the periphery of the substrate, the surface of the substrate and the chamfered part ridgeline part are greatly scraped off, and the phenomenon that the chamfering width increases by 0.4 mm is recognized, and a method for not changing the chamfering width is started. did.
[0014]
In sandblasting, the blasting material on the airflow basically collides with the workpiece and the removal process proceeds. First, we investigated how the removal characteristics change by changing the airflow. As a method of changing the airflow, a method of arranging a plate material around the substrate was adopted. As a result, it was confirmed that changing the relative height of the plate material installed on the outer periphery from the substrate surface changes the way to remove the ridge line part, and this relative height is examined in more detail, and the arrangement of the plate material described above By this method, sand blasting can be performed while preventing changes in the chamfered shape as much as possible.
[0015]
Here, the protruding height h of the plate material 2 from the surface of the substrate 1 is preferably 5 to 15 mm, particularly preferably 10 to 15 mm. When the protruding height h is less than 5 mm, the wear of the ridge line portion 4 of the ridge line portion 4 between the surface of the substrate 1 and the chamfered surface 3 in FIG. 1 proceeds, and the object of the present invention may not be achieved. If the thickness exceeds 15 mm, wear of the ridge line portion 4 can be suppressed, but the removal of the substrate surface in the vicinity of the ridge line portion 4 does not proceed, resulting in a swell (see FIG. 2). . And when this swell part 10 remains, there exists a possibility of becoming the cause of a leak by vacuum suction.
The material of the plate material is preferably a material that is not easily worn by sandblasting, and examples thereof include polyurethane resin.
[0016]
As the sandblasting method, a known method can be adopted, and for example, processing can be performed using the apparatus of FIG. Here, in the figure, 20 is a substrate holder, 21 is a sandblast nozzle, and 22 is an air flow of abrasive grains. In addition, 1 is a board | substrate and the board | plate material 2 is not illustrated.
[0017]
In this case, the machining tool has a structure that can be arbitrarily moved in the X and Y directions, and the movement can be controlled by a computer. Processing can also be performed with an X-θ mechanism. The air pressure is related to the distance between the abrasive grains used and the processing tool substrate, and is not uniquely determined, and can be adjusted by looking at the removal speed and the processing strain depth.
[0018]
When sandblasting according to the present invention, the height data is stored in a computer based on the flatness data measured in advance, and the moving time of the sandblast nozzle is slowed at the high part to increase the residence time, while the low part On the other hand, it is possible to perform processing while controlling the staying time such as increasing the moving speed of the sandblast nozzle and shortening the residence time.
[0019]
In addition, since this manufacturing method selectively removes only a high portion of the substrate, it is possible to reliably improve a substrate with poor flatness, and a high flatness substrate can be obtained by precise control of a processing tool. In addition, the flatness of the substrate can be improved in a short time by rough control.
Then, the dimension measurement of a ridgeline part is performed. A scale loupe can be used for the dimension measurement, and a undulation meter (manufactured by Tokyo Seimitsu Co., Ltd.) can be used for the shape measurement of the ridge line portion.
[0020]
In addition, according to the Example mentioned later, the mode that the ridgeline part was selectively removed was not seen only in the chamfering width having a dimensional change according to the surface removal amount by sandblasting. It was also confirmed that the vicinity of the ridge line was removed by the undulation meter.
[0021]
In addition, when the air pressure or the grain size of the abrasive grains changes, the airflow naturally changes and the processing characteristics of the ridge line portion also change. However, considering practicality such as processing strain and processing time, the air pressure is 0. .05 to 0.15 MPa, and the abrasive grain size is preferably # 600 to # 3000.
[0022]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
[0023]
[Example 1]
A synthetic quartz substrate having a size of 620 × 720 mm and a thickness of 9.0 mm was processed with a double-sided lapping apparatus that performs planetary motion using GC # 600 (manufactured by Fujimi Abrasives Co., Ltd.) to prepare a raw material substrate. . The chamfering at this time was 45 ° and 0.9 mm, the accuracy of the raw material substrate was 4 μm in parallel and 67 μm in flatness, and the short side of the substrate was high. In addition, the flatness tester (made by Kuroda Seiko Co., Ltd.) was used for the measurement of parallelism and flatness.
[0024]
Then, this plate was mounted on the substrate holder of the apparatus shown in FIG. At that time, a polyurethane resin plate material was placed 10 mm higher than the substrate surface around the substrate so as to surround the substrate. In this case, a device having a structure in which a processing tool can be attached to a motor and rotated and a structure in which the processing tool can be pressurized with air was used. Further, the processing tool has a structure that can move substantially parallel to the substrate holder in the X and Y axis directions.
[0025]
As the abrasive grain of the blast material, FO # 1000 (manufactured by Fujimi Abrasive Co., Ltd.) was used, and the air pressure was set to 0.1 MPa.
A sandblast nozzle having a rectangular shape of 1 mm × 40 mm was used, and the distance between the sandblast nozzle and the substrate surface was 40 mm.
As the processing method, as indicated by an arrow in FIG. 4, the sandblast nozzle was continuously moved in parallel with the X axis, and the Y axis direction was moved at a pitch of 30 mm.
[0026]
The movement speed of the sandblast nozzle is 50 mm / sec at the lowest substrate outer periphery in the substrate shape, and the movement speed at each part of the substrate is obtained from the processing speed to obtain the required stay time of the sandblast nozzle at each part of the substrate. The processing position was moved by moving the stage by calculation, and both sides were processed. Further, the processing was performed with the sandblast removal amount at the highest position of the short side of the substrate set to 100 μm.
[0027]
Then, the board | substrate was taken out and the chamfering width measurement and the waviness measurement of the ridgeline part were performed.
The chamfer width was inspected using a scale loupe with a resolution of 0.05 mm. As a result, the change in the chamfer width was only 0.1 mm smaller, and the chamfer width was reduced according to the surface removal amount by sandblasting. Further, even with the undulation meter, no rise of the substrate surface in the vicinity of the chamfered ridgeline was observed.
[0028]
[Example 2]
The same procedure as in Example 1 was performed, except that the polyurethane resin plate material around the substrate was placed 5 mm higher than the substrate surface.
[0029]
[Example 3]
The same procedure as in Example 1 was performed, except that the polyurethane resin plate material around the substrate was placed 15 mm higher than the substrate surface.
[0030]
[Example 4]
The same procedure as in Example 1 was performed except that the abrasive grains were GC # 3000 and the air pressure was 0.15 MPa.
[0031]
[Example 5]
The same procedure as in Example 1 was performed except that the abrasive grains were FO # 1000 and the air pressure was 0.15 MPa.
[0032]
[Example 6]
The same procedure as in Example 1 was performed except that the abrasive grains were FO # 800 and the air pressure was 0.08 MPa.
[0033]
[Comparative Example 1]
The same procedure as in Example 1 was performed, except that the polyurethane resin plate material around the substrate and the substrate surface were arranged at the same height.
[0034]
[Comparative Example 2]
The same procedure as in Example 1 was performed, except that the urethane plate material around the substrate was placed 4 mm lower than the substrate surface.
The results are shown in Table 1.
[0035]
[Table 1]

[0036]
The chamfered width of 0.9 mm before processing is 0.8 mm when the chamfered portion is not selectively removed because the surface is removed by 0.1 mm after processing. For this reason, in the case of 0.8 mm, the amount of change in the chamfer width is expressed as 0, and + indicates that the chamfer width is larger than 0.8 mm.
[0037]
【The invention's effect】
According to the present invention, local wear of the ridge line portion between the substrate surface and the chamfered surface is eliminated, thereby preventing the risk of vacuum leak due to substrate adsorption during exposure, and eliminating adsorption failure during exposure.
[Brief description of the drawings]
FIGS. 1A and 1B show an arrangement of a substrate and a plate material, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view.
FIG. 2 is a partially omitted cross-sectional view showing a swell phenomenon due to the progress of removal of the substrate surface in the vicinity of the ridge line;
FIG. 3 is a perspective view showing an outline of a processing apparatus.
FIG. 4 is a perspective view showing a movement mode in sandblasting.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Board | plate material 3 Chamfering surface 4 Edge line part 10 Swelling part 20 Board | substrate holding stand 21 Sand blast nozzle 22 Airflow of abrasive grain

Claims (5)

When sandblasting a synthetic quartz substrate having a chamfered peripheral part, a plate material is disposed on the peripheral part of the substrate in contact with or in proximity to the surface of the substrate so as to protrude 5 to 15 mm from the substrate surface to the blast nozzle side. A substrate processing method comprising sandblasting a surface. Substrate, the substrate processing method according to claim 1, characterized in that the synthetic quartz substrates for photomasks. The substrate processing method according to claim 1 or 2, wherein the substrate has a diagonal length of 500 mm or more and a thickness of 5 to 20 mm. The substrate processing method according to claim 1, wherein the chamfer width is 0.3 to 1.5 mm. The substrate processing method according to any one of claims 1 to 4, wherein an air pressure of the sandblast is 0.05 to 0.15 MPa and an abrasive grain size is # 600 to # 3000.

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