# US 7,608,542 B2 · Large-size glass substrate for photomask and making method, computer-readable recording medium, and mother glass exposure method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,542 B2 - Document ID: US7608542B2 - Status: Granted - Kind: B2 - Application number: 11/587,902 - Filed: 2006-06-12 - Published: 2008-10-23 - Granted: 2009-10-27 - Earliest claimed: 2005-06-17 - Assignees: Shin-Etsu Chemical Co., Ltd. - Inventors: Shuhei Ueda; Yukio Shibano; Atsushi Watabe; Daisuke Kusabiraki - Web page: https://patentgrep.com/patent/US7608542B2 ## CPC - G11B 7/261: {Preparing a master, e.g. exposing photoresist, electroforming} - G03F 1/60: Substrates - G03F 7/70791: {Large workpieces, e.g. glass substrates for flat panel displays or solar panels} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract A large-size glass substrate, from which a photomask substrate is formed, is prepared by processing a large-size glass substrate stock by (1) a flattening removal quantity based on height data of the substrate stock in the vertical attitude plus a deformation-corrective removal quantity. The deformation-corrective removal quantity is calculated from (2) a deflection of the substrate stock by its own weight in the horizontal attitude, (3) a deformation of the photomask substrate caused by chucking in an exposure apparatus, and (4) an accuracy distortion of a platen for supporting a mother glass. ## Claims ### Claim 1 A method for preparing a large-size glass substrate, from which a photomask substrate is formed, the photomask substrate being used in a mother glass exposure process including attaching a photomask substrate having opposed sides to an exposure apparatus through support of opposed side edges, disposing underneath and adjacent to the photomask substrate a mother glass serving as an array side or color filter side substrate in a TFT liquid crystal panel, and irradiating light from the exposure apparatus to the mother glass through the photomask substrate, said method comprising the step of processing a large size glass substrate stock having front and back surfaces and a diagonal length of at least 500 mm into the large-size glass substrate, by removing therefrom (1) a flattening removal quantity of material based on a height data of the flatness and parallelism of the front and back surfaces of the large-size glass substrate stock in the vertical attitude, plus a deformation-corrective removal quantity of material, the deformation-corrective removal quantity being calculated from (2) a deflection of the substrate stock by its own weight in the horizontal attitude, calculated from the thickness and size of the substrate stock, and the support position when the photomask substrate is horizontally supported, (3) a deformation of the photomask substrate caused by the photomask substrate support when the photomask substrate is attached to the exposure apparatus, and (4) an accuracy distortion of a platen for supporting the mother glass, wherein the resulting large-size glass substrate has such an arcuate shape in cross section that the surface to be opposed to the mother glass is concave when held vertically, and reduces the proximity gap variation between the mother glass and the photomask substrate formed from the large-size glass substrate which is held horizontally when the opposed side edges of the photomask substrate are supported in the exposure apparatus. ### Claim 2 (depends on 1) The method of claim 1, wherein the method further comprises, after the processing for flattening and deformation-correction step, the post step of polishing the glass substrate on one or both of its surfaces, the deformation-corrective removal quantity being calculated by further adding (5) a change of flatness by the post step of polishing. ### Claim 3 (depends on 1, 2) The method of claim 1 or 2 wherein the removing step uses a processing tool of sand blasting. ### Claim 4 (depends on 3) The method of claim 3 wherein the removing step using a processing tool of sand blasting is performed at a constant pressure. ### Claim 5 (depends on 3) The method of claim 3 wherein the sand blasting uses particles of cerium oxide, silicon oxide, aluminum oxide or silicon carbide. ### Claim 6 (depends on 1) The method of claim 1 wherein the surface of the substrate stock at an arbitrary position is processed while the substrate stock and/or the processing tool is moved. ### Claim 7 A large-size glass substrate, from which a photomask substrate is formed, wherein the photomask substrate is used in a mother glass exposure process including attaching a photomask substrate having opposed sides to an exposure apparatus through support of opposed side edges, disposing underneath and adjacent to the photomask substrate a mother glass serving as an array side or color filter side substrate in a TFT liquid crystal panel, and irradiating light from the exposure apparatus to the mother glass through the photomask substrate, said large-size glass substrate is produced by processing a large-size glass substrate stock having front and back surfaces and a diagonal length of at least 500 mm and a thickness of at least 4 mm, by (1) a flattening removal quantity of material based on a height data of the flatness and parallelism of the front and back surfaces of the large-size glass substrate stock in the vertical attitude, plus a deformation-corrective removal quantity of material, the deformation-corrective removal quantity is calculated from (2) a deflection of the substrate stock by its own weight in the horizontal attitude, calculated from the thickness and size of the substrate stock, and the support position when the photomask substrate is horizontally supported, (3) a deformation of the photomask substrate caused by the photomask substrate support when the photomask substrate is attached to the exposure apparatus, and (4) an accuracy distortion of a platen for supporting the mother glass, the large-size glass substrate has such an arcuate shape in cross section that the surface to be opposed to the mother glass is concave when held vertically, and reduces the proximity gap variation between the mother glass and the photomask substrate formed from the large-size glass substrate which is held horizontally when the opposed side edges of the photomask substrate are supported in the exposure apparatus. ### Claim 8 (depends on 7) The large-size glass substrate of claim 7 which has a surface flatness/diagonal length of up to 4.8′10-5 in the horizontal attitude. ### Claim 9 (depends on 7, 8) The large-size glass substrate of claim 7 or 8 which has a diagonal length of up to 825 mm and a thickness from 3 mm to less than 6 mm. ### Claim 10 (depends on 7, 8) The large-size glass substrate of claim 7 or 8 which has a diagonal length of 800 to 1650 mm and a thickness of 6 to 11 mm. ### Claim 11 (depends on 7, 8) The large-size glass substrate of claim 7 or 8 which has a diagonal length of 1800 to 2150 mm and a thickness of 9 to 16 mm. ### Claim 12 (depends on 7, 8) The large-size glass substrate of claim 7 or 8 which has a diagonal length of 2151 to 3000 mm and a thickness of 9 to 20 mm. ### Claim 13 A mother glass exposure process comprising attaching a photomask substrate having opposed sides to an exposure apparatus through support of opposed side edges, disposing underneath and adjacent to the photomask substrate a mother glass serving as an array side or color filter side substrate in a TFT liquid crystal panel, and irradiating light from the exposure apparatus to the mother glass through the photomask substrate, wherein said photomask substrate is formed from a large-size glass substrate which is prepared by processing a large-size glass substrate stock having front and back surfaces and a diagonal length of at least 500 mm and a thickness of at least 4 mm, by (1) a flattening removal quantity of material based on a height data of the flatness and parallelism of the front and back surfaces of the large-size glass substrate stock in the vertical attitude, plus a deformation-corrective removal quantity of material, the deformation-corrective removal quantity is calculated from (2) a deflection of the substrate stock by its own weight in the horizontal attitude, calculated from the thickness and size of the substrate stock, and the support position when the photomask substrate is horizontally supported, (3) a deformation of the photomask substrate caused by the photomask substrate support when the photomask substrate is attached to the exposure apparatus, and (4) an accuracy distortion of a platen for supporting the mother glass, the large-size glass substrate has such an arcuate shape in cross section that the surface to be opposed to the mother glass is concave, when held vertically, the photomask substrate is held horizontally when the opposed side edges of the photomask substrate are supported in the exposure apparatus, whereby the proximity gap variation between the mother glass and the photomask substrate is reduced. ### Claim 14 (depends on 13) The mother glass exposure process of claim 13 wherein the large-size glass substrate has a surface flatness/diagonal length of up to 4.8×10−5 in the horizontal attitude. ### Claim 15 A computer-readable recording medium for recording a method for preparing a large-size glass substrate from a large-size glass substrate stock having front and back surfaces and a diagonal length of at least 500 mm and a thickness of at least 4 mm, a photomask substrate being formed from said large size glass substrate, the photomask substrate being used in a mother glass exposure process including attaching the photomask substrate having opposed sides to an exposure apparatus through support of opposed side edges, disposing underneath and adjacent to the photomask substrate a mother glass serving as an array side or color filter side substrate in a TFT liquid crystal panel, and irradiating light from the exposure apparatus to the mother glass through the photomask substrate, said medium having recorded therein a program for operating the computer to execute the following steps: a step of calculating (1) a flattening removal quantity of material based on a height data of the flatness and parallelism of the front and back surfaces of a large-size glass substrate stock having a diagonal length of at least 500 mm and a thickness of at least 4 mm in the vertical attitude, a step of calculating a deformation-corrective removal quantity of material from (2) a deflection of the substrate stock by its own weight in the horizontal attitude, calculated from the thickness and size of the substrate stock, and the support position when the photomask substrate is horizontally supported, (3) a deformation of the photomask substrate caused by the photomask substrate support when the photomask substrate is attached to the exposure apparatus, and (4) an accuracy distortion of a platen for supporting the mother glass, and a step of delivering a command to a processing machine to carry out processing for flattening and deformation-correction by removing a total quantity of material derived from the flattening removal quantity and the deformation-corrective removal quantity. ### Claim 16 (depends on 15) The recording medium of claim 15 wherein the method further comprises, after the processing for flattening and deformation-correction step, the post step of polishing the glass substrate on one or both of its surfaces, the program further includes a step of calculating the total quantity of material by further adding (5) a change of flatness by the post step of polishing.