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:
Dec. 04, 2012
Filed:
Nov. 08, 2010
Shinya Kikugawa, Tokyo, JP;
Akira Takada, Tokyo, JP;
Satoru Takaki, Tokyo, JP;
Yosuke Sato, Tokyo, JP;
Yasuhiko Akao, Yonezawa, JP;
Shinya Kikugawa, Tokyo, JP;
Akira Takada, Tokyo, JP;
Satoru Takaki, Tokyo, JP;
Yosuke Sato, Tokyo, JP;
Yasuhiko Akao, Yonezawa, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
The present invention provides a mask blank which comprises a substrate made of a synthetic quartz glass and a light-shielding film laminated on a surface of the substrate and is for use in a semiconductor device production technique employing an exposure light wavelength of 200 nm or shorter, wherein the mask blank has a birefringence, as measured at a wavelength of 193 nm, of 1 nm or less per substrate thickness. According to the present invention, mask blanks suitable for use in the immersion exposure technique and the polarized illumination technique are provided.