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:
Jul. 03, 2007
Filed:
Mar. 31, 2003
Hideo Kobayashi, Tokyo, JP;
Keishi Asakawa, Tokyo, JP;
Hideo Kobayashi, Tokyo, JP;
Keishi Asakawa, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
In a method of producing a photomask blank, comprising a thin film forming step of forming, on a rectangular substrate, a thin film for causing an optical change in exposure light, a resist application step of applying a positive resist on the thin film, a baking step of heat treating the resist applied on the thin film, and a removing step of removing a resist film formed in a portion of the edge of the substrate, the removing step is carried out by exposing the resist film in the portion of the edge of the substrate after the resist application step and before the heat treating step so that, upon development subsequently carried out in the removing step, a difference in solubility or dissolving speed in a developer is obtained between an exposed area and an unexposed area and by selectively supplying the developer to the exposed area.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile