The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 15, 2012
Filed:
Aug. 26, 2010
Akio Koike, Chiyoda-ku, JP;
Kenta Saito, Chiyoda-ku, JP;
Long Shao, Chiyoda-ku, JP;
Yasutomi Iwahashi, Chiyoda-ku, JP;
Shinya Kikugawa, Chiyoda-ku, JP;
Akio Koike, Chiyoda-ku, JP;
Kenta Saito, Chiyoda-ku, JP;
Long Shao, Chiyoda-ku, JP;
Yasutomi Iwahashi, Chiyoda-ku, JP;
Shinya Kikugawa, Chiyoda-ku, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
The present invention provides a TiO—SiOglass whose coefficient of linear thermal expansion in the range of the time of irradiation with EUV light is substantially zero when used as an optical member of an exposure tool for EUVL and which has extremely high surface smoothness. The present invention relates to a TiO-containing silica glass having a TiOcontent of from 7.5 to 12% by mass, a temperature at which a coefficient of linear thermal expansion is 0 ppb/° C., falling within the range of from 40 to 110° C., and a standard deviation (σ) of a stress level of striae of 0.03 MPa or lower within an area of 30 mm×30 mm in at least one plane.