Covalent Materials Corporation

Coorstek Kk

Sachiko Kato

Yuji Fukasawa

Masanobu Ezaki

Masashi Kobata

Provided is a silica glass member which exhibits high optical transparency to vacuum ultraviolet light and has a low thermal expansion coefficient of 4.0&#xd7;10/K or less at near room temperature, particularly a silica glass member which is suitable as a photomask substrate to be used in a double patterning exposure process using an ArF excimer laser (193 nm) as a light source. The silica glass member is used in a photolithography process using a vacuum ultraviolet light source, in which the fluorine concentration is 1 wt % or more and 5 wt % or less, and the thermal expansion coefficient at from 20&#xb0; C. to 50&#xb0; C. is 4.0&#xd7;10/K or less.

Silica glass member and method of manufacturing the same

To provide titania-silica glass which is transparent glass of low thermal expansion, in particular, is of a low thermal expansion coefficient over a wide range of temperatures of 0 to 100&#xb0; C. (an operating temperature range) when it is used as a photomask or a mirror material in extreme ultraviolet ray lithography, and which is excellent in homogeneity within the field and stability. Titania-silica glass is used which has 8 to 10% by weight of titania and 90 to 92% by weight of silica, where a Ticoncentration is 10 to 60 ppm by weight.

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Hadano, Japan

Sachiko Kato