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:
Sep. 15, 1992
Filed:
May. 24, 1991
Applicant:
Inventors:
Yasutaka Ban, Yokohama, JP;
Kazuo Tokitomo, Kawasaki, JP;
Assignee:
Fujitsu Limited, Kanagawa, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03F / ;
U.S. Cl.
CPC ...
430-5 ; 430-9 ; 430 13 ; 430292 ;
Abstract
A photomask for an ultraviolet light with a contrast of 10 or larger can be fabricated by generating a color center by irradiating a calcium fluoride crystal substrate with a KrF excimer laser (wavelength of 248 nm) with an energy of 10 J/cm.sup.2 through an original photomask formed by a chromium film on a quartz substrate and forming a pattern by a color center corresponding to an original photomask pattern. In the same way, a similar photomask can be fabricated by irradiating a calcium fluoride crystal substrate with X-rays having a wavelength ranging from 0.5 to 1.0 nm through an original mask formed by a gold film on the silicon substrate.