Abstract: On an EUV light-reflecting surface of titania-doped quartz glass, an angle (?) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

Abstract: Methods for selecting titania-doped quartz glass which experiences a reduction in OH group concentration of less than or equal to 100 ppm upon heat treatment at 900° C. for 100 hours as suitable material for the EUV lithography member.

Abstract: Titania-doped quartz glass is manufactured by mixing a silicon-providing reactant gas and a titanium-providing reactant gas, preheating the reactant gas mixture at 200-400° C., and subjecting the mixture to oxidation or flame hydrolysis. A substrate of the glass is free of concave defects having a volume of at least 30,000 nm3 in an effective region of the EUV light-reflecting surface and is suited for use in the EUV lithography.

Abstract: On an EUV light-reflecting surface of titania-doped quartz glass, an angle (?) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

Abstract: Titania-doped quartz glass is manufactured by mixing a silicon-providing reactant gas and a titanium-providing reactant gas, preheating the reactant gas mixture at 200-400° C., and subjecting the mixture to oxidation or flame hydrolysis. A substrate of the glass is free of concave defects having a volume of at least 30,000 nm3 in an effective region of the EUV light-reflecting surface and is suited for use in the EUV lithography.

Abstract: Titania-doped quartz glass is manufactured by mixing a silicon-providing reactant gas and a titanium-providing reactant gas, preheating the reactant gas mixture at 200-400° C., and subjecting the mixture to oxidation or flame hydrolysis. A substrate of the glass is free of concave defects having a volume of at least 30,000 nm3 in an effective region of the EUV light-reflecting surface and is suited for use in the EUV lithography.

Abstract: On an EUV light-reflecting surface of titania-doped quartz glass, an angle (?) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

Abstract: A member is made of titania-doped quartz glass in which striae have a curvature radius of at least 150 mm in a surface perpendicular to an EUV-reflecting surface. The member free of exposed striae and having a high flatness is useful in EUV lithography.

Abstract: Disclosed is a method of producing a synthetic quartz glass for excimer laser by depositing on a target silica particulates obtained by subjecting a silica raw material to vapor-phase hydrolysis or oxidative decomposition in an oxyhydrogen flame in a vacuum sintering furnace to form a porous silica base material, vitrifying the porous silica base material, and subjecting the vitrified material to hot forming, an annealing treatment and a hydrogen doping treatment, wherein the vitrification of the porous silica base material includes: (a) a step of holding a vacuum pressure at or below 20.0 Pa in a temperature range from 400° C., inclusive, to 900° C., exclusive; (b) a step of holding a vacuum pressure at or below 10.0 Pa in a temperature range from 900° C., inclusive, to 1100° C., exclusive; and (c) a step of holding a vacuum pressure at or below 3.0 Pa in a temperature range from 1100° C. to a transparent-vitrification temperature.

Abstract: Synthetic quartz glass is prepared by subjecting a silicon-providing feedstock to flame hydrolysis in oxyhydrogen flame, depositing silica fine particles on a rotating quartz glass target while concurrently melting and vitrifying them, thereby forming a synthetic quartz glass ingot, shaping, annealing, and effecting dehydrogenation treatment at a temperature of at least 600° C. and a pressure of up to 5 Pa for a holding time of at least 12 hours. The synthetic quartz glass has a high helium gas permeability and is suited for forming nanoimprint molds.

Abstract: A titania-doped quartz glass suited as an EUV lithographic member is prepared by feeding a silicon-providing reactant gas and a titanium-providing reactant gas through a burner along with hydrogen and oxygen, subjecting the reactant gases to oxidation or flame hydrolysis to form synthetic silica-titania fine particles, depositing the particles on a rotating target, and concurrently melting and vitrifying the deposited particles to grow an ingot of titania-doped quartz glass. The target is retracted such that the growth front of the ingot may be spaced a distance of at least 250 mm from the burner tip.

Abstract: A member is made of titania-doped quartz glass in which striae have a curvature radius of at least 150 mm in a surface perpendicular to an EUV-reflecting surface. The member free of exposed striae and having a high flatness is useful in EUV lithography.

Abstract: Synthetic quartz glass is prepared by subjecting a silicon-providing feedstock to flame hydrolysis in oxyhydrogen flame, depositing silica fine particles on a rotating quartz glass target while concurrently melting and vitrifying them, thereby forming a synthetic quartz glass ingot, shaping, annealing, and effecting dehydrogenation treatment at a temperature of at least 600° C. and a pressure of up to 5 Pa for a holding time of at least 12 hours. The synthetic quartz glass has a high helium gas permeability and is suited for forming nanoimprint molds.

Abstract: A titania and sulfur co-doped quartz glass member is provided. Due to co-doping of titania and sulfur, the quartz glass member undergoes zero expansion at a certain temperature and low thermal expansion over a wide temperature range, and is thus suited for use in a commercial EUV lithography tool. A manufacturing method and an optical member for EUV lithography are also provided.

Abstract: Methods for selecting titania-doped quartz glass which experiences a reduction in OH group concentration of less than or equal to 100 ppm upon heat treatment at 900° C. for 100 hours as suitable material for the EUV lithography member.

Abstract: A titania and sulfur co-doped quartz glass member is provided. Due to co-doping of titania and sulfur, the quartz glass member undergoes zero expansion at a certain temperature and low thermal expansion over a wide temperature range, and is thus suited for use in a commercial EUV lithography tool. A manufacturing method and an optical member for EUV lithography are also provided.

Abstract: Titania-doped quartz glass is manufactured by mixing a silicon-providing reactant gas and a titanium-providing reactant gas, preheating the reactant gas mixture at 200-400° C., and subjecting the mixture to oxidation or flame hydrolysis. A substrate of the glass is free of concave defects having a volume of at least 30,000 nm3 in an effective region of the EUV light-reflecting surface and is suited for use in the EUV lithography.

Abstract: In a titania-doped quartz glass member having a surface where EUV light of up to 70 nm wavelength is reflected, a refractive index distribution in the surface has only one extreme point within a central 80% region of the member. The titania-doped quartz glass member has a surface with a high level of precision and thus can be formed into an EUV lithography photomask substrate which is improved in flatness and thermal expansion properties.

Abstract: On an EUV light-reflecting surface of titania-doped quartz glass, an angle (?) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

Abstract: In a titania-doped quartz glass member having a surface where EUV light of up to 70 nm wavelength is reflected, a refractive index distribution in the surface has only one extreme point within a central 80% region of the member. The titania-doped quartz glass member has a surface with a high level of precision and thus can be formed into an EUV lithography photomask substrate which is improved in flatness and thermal expansion properties.