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. 18, 2008
Filed:
Jul. 23, 2004
Tsuneo Numanami, Niigata-ken, JP;
Masayuki Nakatsu, Niigata-ken, JP;
Masayuki Mogi, Niigata-ken, JP;
Tsuneyuki Hagiwara, Tokyo, JP;
Naoto Kondo, Tokyo, JP;
Tsuneo Numanami, Niigata-ken, JP;
Masayuki Nakatsu, Niigata-ken, JP;
Masayuki Mogi, Niigata-ken, JP;
Tsuneyuki Hagiwara, Tokyo, JP;
Naoto Kondo, Tokyo, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A photomask blank substrate is made by polishing a starting substrate to a specific flatness in a principal surface region on a top surface of the substrate so as to form a polished intermediate product, then additionally polishing the intermediate product. Substrates made in this way exhibit a good surface flatness at the time of wafer exposure. When a photomask fabricated from a blank obtained from such a substrate is held on the mask stage of a wafer exposure system with a vacuum chuck, the substrate surface undergoes minimal warping, enabling exposure patterns of small geometry to be written onto wafers to good position and linewidth accuracies.