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:
Dec. 19, 2000
Filed:
Oct. 23, 1998
Virginia Chi-Chuen Chao, Essex Jct., VT (US);
Scott A Estes, Essex Junction, VT (US);
Thomas B Faure, Georgia, VT (US);
Thomas M Wagner, South Burlington, VT (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for forming chrome photomasks and phase-shift masks without producing chrome opaque defects. The method involves rinsing the mask blank with dilute acid, preferably nitric or perchloric acid, during processing to form the photomask. When a dry etch is used to form the photomask, the mask blank is rinsed after wet development of the photoresist. When a wet etch is used to form the photomask, the mask blank is rinsed after the wet etch. This method decreases the number of defects per photomask as well as the mask-to-mask variation in the number of defects.