Shin-etsu Chemical Co., Ltd.

Osamu Sekizawa

Hisatoshi Otsuka

Kazuo Shirota

Shigeru Maida

Naoki Yanagisawa

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.

Titania-doped quartz glass and making method

A synthetic quartz glass ingot is prepared by vapor phase hydrolyzing or oxidatively decomposing a silica feedstock in a flame to form fine particles of silica, depositing the silica particles on a target and melting and vitrifying the particles to form a synthetic quartz glass ingot on the target while the target is moved back and forth. The method further comprises: (i) continuously feeding the silica feedstock at a predetermined rate, (ii) keeping the flame in constant contact with an overall growing face, (iii) cyclically repeating the back and forth movement of the target at a predetermined speed, and (iv) maintaining the shape of the growing ingot unchanged.

Manufacture of synthetic quartz glass ingot and synthetic quartz glass member

When a synthetic quartz glass substrate is prepared from a synthetic quartz glass block, (I) the block has a hydrogen molecule concentration of 5&#xd7;10-1&#xd7;10molecules/cm, (II) the substrate has a hydrogen molecule concentration of 5&#xd7;10-5&#xd7;10molecules/cm, (III) the substrate has an in-plane variation of its internal transmittance at 193.4 nm which is up to 0.2%, and (IV) the substrate has an internal transmittance of at least 99.6% at 193.4 nm. The synthetic quartz glass substrate has a high transmittance and a uniform transmittance distribution, and is adapted for use with excimer lasers, particularly ArF excimer lasers.

Synthetic quartz glass substrate for excimer lasers and making method

A synthetic quartz glass substrate having (i) an OH concentration of 1-100 ppm and a hydrogen molecule concentration of 1&#xd7;10-1&#xd7;10molecules/cm, (ii) an in-plane variation of its internal transmission at wavelength 193.4 nm which is up to 0.2%, and (iii) an internal transmission of at least 99.6% at wavelength 193.4 nm is suited for use with excimer lasers.

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Joetsu, Japan

Osamu Sekizawa