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:
Mar. 29, 2016
Filed:
Apr. 09, 2012
Shigeru Maida, Joetsu, JP;
Hisatoshi Otsuka, Joetsu, JP;
Tetsuji Ueda, Koriyama, JP;
Masanobu Ezaki, Koriyama, JP;
Shigeru Maida, Joetsu, JP;
Hisatoshi Otsuka, Joetsu, JP;
Tetsuji Ueda, Koriyama, JP;
Masanobu Ezaki, Koriyama, JP;
SHIN-ETSU CHEMICAL CO., LTD., Tokyo, JP;
Abstract
On an EUV light-reflecting surface of titania-doped quartz glass, an angle (θ) 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.