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:
Feb. 28, 2023
Filed:
Jul. 20, 2020
Applicant:
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Inventors:
Yoko Ishitsuka, Joetsu, JP;
Atsushi Watabe, Joetsu, JP;
Daijitsu Harada, Joetsu, JP;
Masaki Takeuchi, Joetsu, JP;
Assignee:
SHIN-ETSU CHEMICAL CO., LTD., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03F 1/60 (2012.01); C03C 19/00 (2006.01); G01B 5/28 (2006.01); C03C 3/06 (2006.01); B24B 1/00 (2006.01);
U.S. Cl.
CPC ...
C03C 19/00 (2013.01); B24B 1/00 (2013.01); C03C 3/06 (2013.01); G01B 5/285 (2013.01); G03F 1/60 (2013.01); C03C 2204/08 (2013.01);
Abstract
A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 μm. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.