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:
Jan. 04, 1994
Filed:
Dec. 24, 1991
Applicant:
Inventor:
Hiroyoshi Tanabe, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03F / ;
U.S. Cl.
CPC ...
430-5 ; 430320 ; 430321 ;
Abstract
A phase shifting mask includes an opaque layer having three adjacent apertures which comprise a predetermined pattern, and at least two phase shifters each having a different shift amount. At least two of the apertures are covered with the phase shifters so that a phase difference between each two adjacent apertures is approximately 120.degree. (1/3.lambda.). Therefore, light intensity at a medial area between each two adjacent aperture is decreased in comparison with independent lights passing through the apertures.