Abstract: A large-sized substrate having a diagonal length of not less than 500 mm and a ratio of flatness/diagonal length of not more than 6×10?6 is disclosed. By use of the large-sized substrate for exposure of the present invention, the exposure accuracy, particularly the register accuracy and resolution are enhanced, so that it is possible to achieve high-precision exposure of a large-sized panel. With the processing method according to the present invention, it is possible to stably obtain a large-sized photomask substrate with a high flatness, and since the CD accuracy (dimensional accuracy) at the time of exposure of the panel is enhanced, it is possible to perform exposure of a fine pattern, leading to a higher yield of the panel. Furthermore, by applying the processing method according to the present invention, it is also possible to create an arbitrary surface shape.

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.

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.

Abstract: A process for stably and efficiently producing quality glass articles such as preforms at high yields, and a process for producing an optical device from the preform obtained by the above process. In the process for producing a glass article, molten glass gobs having a predetermined weight each are poured, or molten glass drops having a predetermined weight each are dropped through a nozzle, into a boiling liquid having a boiling point lower than the class transition temperature of the glass constituting said glass article or a liquid which is temperature-adjusted beforehand so as to be caused to boil by the amount of heat of the glass, to form glass articles.

Abstract: A process for stably and efficiently producing quality glass articles such as preforms at high yields, and a process for producing an optical device from the preform obtained by the above process. In the process for producing a glass article, molten glass gobs having a predetermined weight each are poured, or molten glass drops having a predetermined weight each are dropped through a nozzle, into a boiling liquid having a boiling point lower than the glass transition temperature of the glass constituting said glass article or a liquid which is temperature-adjusted beforehand so as to be caused to boil by the amount of heat of the glass, to form glass articles. In the process for producing an optical device, a preform obtained by the above process is softened by heating and precision-press-molded into the optical device.

Abstract: A large-sized substrate having a diagonal length of not less than 500 mm and a ratio of flatness/diagonal length of not more than 6×10?6 is disclosed. By use of the large-sized substrate for exposure of the present invention, the exposure accuracy, particularly the register accuracy and resolution are enhanced, so that it is possible to achieve high-precision exposure of a large-sized panel. With the processing method according to the present invention, it is possible to stably obtain a large-sized photomask substrate with a high flatness, and since the CD accuracy (dimensional accuracy) at the time of exposure of the panel is enhanced, it is possible to perform exposure of a fine pattern, leading to a higher yield of the panel. Furthermore, by applying the processing method according to the present invention, it is also possible to create an arbitrary surface shape.

Abstract: A functional optical device has cores which are trenches, different portions of the cores being formed from different core materials. The optical device can be formed by forming trenches 5, 7, 9 within a substrate (normally a substrate 1 covered by a cladding layer 3), covering at least part of at least one trench 7 with a cover 11, depositing a first cladding layer 13 of a first cladding material to fill the trenches 5, 9 which are not covered, removing the cover 11, depositing a second cladding layer 15 of a second cladding material to fill the trenches 7 which were previously covered, removing core material outside the trenches 5, 7, 9, and applying a cladding layer to cover the trenches.

Abstract: A large-sized substrate having a diagonal length of not less than 500 mm and a ratio of flatness/diagonal length of not more than 6.0×10?6 is disclosed. By use of the large-sized substrate for exposure of the present invention, the exposure accuracy, particularly the register accuracy and resolution are enhanced, so that it is possible to achieve high-precision exposure of a large-sized panel. With the processing method according to the present invention, it is possible to stably obtain a large-sized photomask substrate with a high flatness, and since the CD accuracy (dimensional accuracy) at the time of exposure of the panel is enhanced, it is possible to perform exposure of a fine pattern, leading to a higher yield of the panel. Furthermore, by applying the processing method according to the present invention, it is also possible to create an arbitrary surface shape.

Abstract: A functional optical device has cores which are trenches, different portions of the cores being formed from different core materials. The optical device can be formed by forming trenches 5,7,9 within a substrate (normally a substrate 1 covered by a cladding layer 3), covering at least part of at least one trench 7 with a cover 11, depositing a first cladding material to fill the trenches 5,9 which are not covered, removing the cover 11, depositing a second cladding layer 15 of a second cladding material to fill the trenches 7 which were previously covered, removing core material outside the trenches 5,7,9 and applying a cladding layer to cover the trenches.

Abstract: A large-size substrate having improved flatness is prepared by measuring the flatness of one surface or opposite surfaces of a large-size substrate having a diagonal length of at least 500 mm, and partially removing raised portions on the one surface or opposite surfaces of the substrate by means of a processing tool on the basis of the measured data. The processing tool is adapted to blast a slurry of microparticulates in water carried on compressed air against the substrate.

Abstract: A large-size substrate having improved flatness is prepared by measuring the flatness of one surface or opposite surfaces of a large-size substrate having a diagonal length of at least 500 mm, and partially removing raised portions on the one surface or opposite surfaces of the substrate by means of a processing tool on the basis of the measured data. The processing tool is adapted to blast a slurry of microparticulates in water carried on compressed air against the substrate.

Abstract: A silica glass substrate is obtained by polishing, cleaning, drying and etching a silica glass substrate slice. When the substrate on one surface is treated with a reactive reagent, defects having a size of at least 0.3 ?m in a direction parallel to the substrate major surface are absent on the substrate surface. The silica glass substrate, in which no submicron defects manifest on the substrate surface even when treated as by cleaning or etching, serves as a reticle for use in photolithographic IC fabrication, achieving an improved manufacturing yield in the semiconductor device fabrication and microelectronic system fields.

Abstract: A functional optical device has cores which are trenches, different portions of the cores being formed from different core materials. The optical device can be formed by forming trenches 5,7,9 within a substrate (normally a substrate 1 covered by a cladding layer 3), covering at least part of at least one trench 7 with a cover 11, depositing a first cladding material to fill the trenches 5,9 which are not covered, removing the cover 11, depositing a second cladding layer 15 of a second cladding material to fill the trenches 7 which were previously covered, removing core material outside the trenches 5,7,9 and applying a cladding layer to cover the trenches.

Abstract: A large-sized substrate having a diagonal length of not less than 500 mm and a ratio of flatness/diagonal length of not more than 6.0×10−6 is disclosed. By use of the large-sized substrate for exposure of the present invention, the exposure accuracy, particularly the register accuracy and resolution are enhanced, so that it is possible to achieve high-precision exposure of a large-sized panel. With the processing method according to the present invention, it is possible to stably obtain a large-sized photomask substrate with a high flatness, and since the CD accuracy (dimensional accuracy) at the time of exposure of the panel is enhanced, it is possible to perform exposure of a fine pattern, leading to a higher yield of the panel. Furthermore, by applying the processing method according to the present invention, it is also possible to create an arbitrary surface shape.

Abstract: A process for stably and efficiently producing quality glass articles such as preforms at high yields, and a process for producing an optical device from the preform obtained by the above process.

Abstract: A silica glass substrate is obtained by polishing, cleaning, drying and etching a silica glass substrate slice. When the substrate on one surface is treated with a reactive reagent, defects having a size of at least 0.3 &mgr;m in a direction parallel to the substrate major surface are absent on the substrate surface. The silica glass substrate, in which no submicron defects manifest on the substrate surface even when treated as by cleaning or etching, serves as a reticle for use in photolithographic IC fabrication, achieving an improved manufacturing yield in the semiconductor device fabrication and microelectronic system fields.