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. 24, 1998
Filed:
Jan. 13, 1997
Keiji Hashimoto, Tokyo, JP;
Junji Fujikawa, Tokyo, JP;
Hiroshi Mohri, Tokyo, JP;
Masahiro Takahashi, Tokyo, JP;
Hiroyuki Miyashita, Tokyo, JP;
Yukio Iimura, Tokyo, JP;
Dai Nippon Printing Co., Ltd., Tokyo, JP;
Abstract
The invention relates a halftone phase shift photomask and a blank therefor, which enables the transmittance of a phase shift portion to be varied even after blank or photomask fabrication, can accommodate to a variety of patterns, and can be fabricated on a mass scale. The exposure light transmittance of a halftone phase shift layer is arbitrarily variable within the range of 1% to 50%, inclusive, by exposing the blank or photomask to a high temperature elevated to at least 150.degree. C., to an oxidizing atmosphere, or to a reducing atmosphere at a step that can provided independent of the steps for film-forming or photomask fabrication step. This enables the exposure light transmittance of the halftone phase shift layer to be changed to any desired value after blank or photomask fabrication, and so an optimal halftone phase shift photomask to be obtained depending on the size, area, location, shape, and the like of the transferred pattern.