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:
Aug. 19, 2008
Filed:
Aug. 19, 2003
Kesahiro Koike, Tokyo, JP;
Junji Miyagaki, Tokyo, JP;
Kesahiro Koike, Tokyo, JP;
Junji Miyagaki, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
In a method of producing a glass substrate for a mask blank, a surface of the glass substrate is polished by the use of a polishing liquid having a pH value between 7.0 and 7.6 that contains abrasive grains, and the abrasive grains include colloidal silica abrasive grains produced by hydrolysis of an organosilicon compound. The polishing process includes a surface roughness control step for initially finishing the surface of the glass substrate to a predetermined surface roughness by moving a polishing member and the glass substrate relative to each other under a predetermined pressure. This is followed by a protrusion suppressing step, carried out immediately before the end of the polishing process, under a pressure lower than the predetermined pressure, to minimize polishing rate and suppress occurrence of a fine convex protrusion. A mask blank and then a transfer mask are formed from this polished glass substrate.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile