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:
Apr. 01, 2008
Filed:
Jul. 23, 2004
Masayuki Nakatsu, Niigata-ken, JP;
Tsuneo Numanami, Niigata-ken, JP;
Masayuki Mogi, Niigata-ken, JP;
Masamitsu Itoh, Yokohama, JP;
Tsuneyuki Hagiwara, Tokyo, JP;
Naoto Kondo, Tokyo, JP;
Masayuki Nakatsu, Niigata-ken, JP;
Tsuneo Numanami, Niigata-ken, JP;
Masayuki Mogi, Niigata-ken, JP;
Masamitsu Itoh, Yokohama, JP;
Tsuneyuki Hagiwara, Tokyo, JP;
Naoto Kondo, Tokyo, JP;
Shin-Etsu Chemical Co., Ltd., Chiyoda-ku, Tokyo, JP;
Kabushiki Kaisha Toshiba, Minato-ku, Tokyo, JP;
Nikon Corporation, Chiyoda-ku, Tokyo, JP;
Abstract
In a quadrangular photomask blank substrate with a length on each side of at least 6 inches, which has a pair of strip-like regions that extend from 2 to 10 mm inside each of a pair of opposing sides along an outer periphery of a substrate top surface, with a 2 mm edge portion excluded at each end, each strip-like region is inclined downward toward the outer periphery of the substrate, and a difference between maximum and minimum values for height from a least squares plane for the strip-like region to the strip-like region is at most 0.5 μm. The substrate exhibits a good surface flatness at the time of wafer exposure.