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:
Nov. 01, 2011
Filed:
Sep. 18, 2009
Masahiro Hashimoto, Shinjuku-ku, JP;
Hideaki Mitsui, Shinjuku-ku, JP;
Masahiro Hashimoto, Shinjuku-ku, JP;
Hideaki Mitsui, Shinjuku-ku, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A photomask blank is for fabricating a phase shift mask having a light-transmissive substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light. The phase shift part is a dug-down part formed by digging down the light-transmissive substrate from a surface thereof to a digging depth adapted to produce the predetermined phase difference with respect to exposure light transmitted through the light-transmissive substrate at a portion where the phase shift part is not provided. The photomask blank includes a light-shielding part formed in a peripheral area around a transfer pattern area of the surface of the light-transmissive substrate and adapted to shield exposure light and further includes an etching mask film formed in the transfer pattern area of the surface of the light-transmissive substrate and made of a material being substantially dry-etchable with a chlorine-based gas, but not substantially dry-etchable with a fluorine-based gas, the etching mask film serving as an etching mask at least until the digging depth is reached when forming the dug-down part.