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. 13, 2021
Filed:
Jun. 04, 2018
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Takuro Kosaka, Joetsu, JP;
Tsuneo Terasawa, Joetsu, JP;
Shigeo Irie, Joetsu, JP;
Takahiro Kishita, Joetsu, JP;
SHIN-ETSU CHEMICAL CO., LTD., Tokyo, JP;
Abstract
A photomask blank is processed into a transmissive photomask for use in photolithography for forming a pattern on a recipient using exposure light. The photomask blank comprises a transparent substrate, a first film of a material which is etchable by chlorine/oxygen-based dry etching, and a second film of a silicon-containing material. The second film includes a layer having a refractive index n of at least 1.6 or an extinction coefficient k of at least 0.3 with respect to the wavelength of inspection light which is longer than the exposure light.