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:
Sep. 03, 2013
Filed:
Jun. 17, 2011
Applicants:
Kenji Okamura, Tokyo, JP;
Masabumi Ito, Tokyo, JP;
Hiroshi Kojima, Tokyo, JP;
Inventors:
Assignee:
Asahi Glass Company, Limited, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G03F 1/24 (2012.01); G03F 1/22 (2012.01);
U.S. Cl.
CPC ...
Abstract
The present invention relates to a low expansion glass substrate which serves as a substrate of a reflective mask used in a lithography step of semiconductor production steps, wherein two side surfaces positioned to face each other among side surfaces formed along a periphery of the low expansion glass substrate, each have a flatness of 25 μm or less.