Shin-etsu Chemical Co., Ltd.

Shigeru Maida

Hisatoshi Otsuka

Tetsuji Ueda

Masanobu Ezaki

Motoyuki Yamada

Kazuo Shirota

Koji Matsuo

Osamu Sekizawa

Naoki Yanagisawa

On an EUV light-reflecting surface of titania-doped quartz glass, an angle (&#x3b8;) 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.

Titania-doped quartz glass and making method

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&#xb0; C. for 100 hours as suitable material for the EUV lithography member.

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&#xb0; 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 nmin an effective region of the EUV light-reflecting surface and is suited for use in the EUV lithography.

Titania doped quartz glass and making method

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.

EUV lithography member, making method, and titania-doped quartz glass

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&#xb0; C., inclusive, to 900&#xb0; C., exclusive; (b) a step of holding a vacuum pressure at or below 10.0 Pa in a temperature range from 900&#xb0; C., inclusive, to 1100&#xb0; C., exclusive; and (c) a step of holding a vacuum pressure at or below 3.0 Pa in a temperature range from 1100&#xb0; C. to a transparent-vitrification temperature.

Method of producing synthetic quartz glass for excimer laser

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&#xb0; 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.

Nanoimprint mold-forming synthetic quartz glass and making method

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.

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.

Titania and sulfur co-doped quartz glass member and making method

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.

Titania-doped quartz glass member and making method

In the nanoimprint lithography, a titania-doped quartz glass having a CTE of &#x2212;300 to 300 ppb/&#xb0; C. between 0&#xb0; C. and 250&#xb0; C. and a CTE distribution of up to 100 ppb/&#xb0; C. at 25&#xb0; C. is suited for use as nanoimprint molds.

Titania-doped quartz glass for nanoimprint molds

In the nanoimprint lithography, titania-doped quartz glass having an internal transmittance distribution of up to 10% at wavelength 365 nm is suited for use as nanoimprint molds.

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Joetsu, Japan

Shigeru Maida