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. 21, 1999
Filed:
Feb. 26, 1998
Tadao Yasuzato, Tokyo, JP;
Shinji Ishida, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A photomask used for a projection exposure equipment comprises a transparent substrate and a light intercepting film provided on the transparent substrate. The transparent substrate comprises a main pattern region and an auxiliary pattern region provided in a periphery of the main pattern region. The auxiliary pattern region is etched to a depth at which a phase difference arises between light transmitted through the main pattern and light transmitted through the auxiliary pattern. The phase difference is of substantially an integral number of times as large as 360 degrees, wherein the integral number is one selected from the group consisting of integral numbers of one or more and integral numbers of minus one or less. The light intercepting film comprises openings on the main pattern region and the auxiliary pattern region.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile