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:
Jul. 14, 2020
Filed:
Feb. 22, 2018
Applicant:
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Inventors:
Souichi Fukaya, Echizen, JP;
Yukio Inazuki, Joetsu, JP;
Assignee:
SHIN-ETSU CHEMICAL CO., LTD., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03F 1/26 (2012.01); G03F 1/32 (2012.01); G03F 1/46 (2012.01); G03F 1/50 (2012.01); G03F 1/58 (2012.01); G03F 1/80 (2012.01); G03F 7/20 (2006.01);
U.S. Cl.
CPC ...
G03F 1/50 (2013.01); G03F 1/26 (2013.01); G03F 1/32 (2013.01); G03F 1/46 (2013.01); G03F 1/58 (2013.01); G03F 1/80 (2013.01); G03F 7/70283 (2013.01);
Abstract
A photomask blank has on a transparent substrate, an optional first film, a second film, a third film, and a fourth film. The first and third films are formed of silicon-containing materials which are resistant to chlorine base dry etching and removable by fluorine base dry etching. The second and fourth films are formed of chromium-containing materials which are resistant to fluorine base dry etching and removable by chlorine base dry etching. An etching clear time of the fourth film is longer than an etching clear time of the second film, on chlorine base dry etching.