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:
Mar. 22, 2005
Filed:
Apr. 19, 2002
Masaki Takeuchi, Nakakubiki-gun, JP;
Yukio Shibano, Nakakubiki-gun, JP;
Masaki Takeuchi, Nakakubiki-gun, JP;
Yukio Shibano, Nakakubiki-gun, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
A glass substrate is to be used as a photomask having a patterned light-shielding film on a surface thereof and thus exposed to light. The substrate is leveled by local plasma etching such that an exposure surface may have a flatness of 0.04-2.2 nm/cm. Since the glass substrate is configured such that the exposure surface or hold surface of the resulting photomask is fully flat during the exposure step, it is suited for use as silica glass substrates for photomasks used in the photolithography of great interest in the fabrication of ICs, thus contributing to the achievement of finer patterns in the semiconductor field.