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:
Mar. 24, 1992
Filed:
Oct. 19, 1989
Minori Noguchi, Yokohama, JP;
Hiroaki Shishido, Yokohama, JP;
Mitsuyoshi Koizumi, Yokohama, JP;
Nobuyuki Akiyama, Yokohama, JP;
Toshihilo Nakata, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Method of inspecting reticles and an apparatus therefor, where means for holding and transferring an inspected reticle and a standard reticle respectively, means for illuminating light with spatial coherency adjusted onto both reticles respectively, and an objective lens for collecting transmitted light or reflected light from the illuminated body produced by the illuminating, are installed on respective Fourier transformation surfaces of both reticle surfaces, and a light blocking plate for blocking light corresponding to the adjusted spatial coherency is installed, and electric signals obtained are compared thereby a defect or a foreign substance existing on the inspected reticle can be detected.