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. 08, 1995
Filed:
Feb. 26, 1993
Applicant:
Inventors:
Akira Shimase, Yokohama, JP;
Junzou Azuma, Yokohama, JP;
Satoshi Haraichi, Tsukuba, JP;
Fumikazu Itoh, Fujisawa, JP;
Yasuhiro Koizumi, Sayama, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03F / ;
U.S. Cl.
CPC ...
430-5 ; 2504922 ;
Abstract
An optical mask for a projection optical system and a method of correcting the mask wherein the mask includes a light intercepting pattern formed on a transparent substrate and a phase shifter for changing the phase of an exposure light provided at predetermined openings of the light intercepting pattern. An etching stopper film which transmits the exposure light is provided between said phase shifter and said light intercepting pattern and for correction of the mask a focused ion beam is utilized for removal of defects by the phase shifter.