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. 13, 1983
Filed:
May. 24, 1982
Mineo Nomoto, Yokohama, JP;
Katsuhiro Iwashita, Yokohama, JP;
Toru Otsubo, Fujisawa, JP;
Susumu Aiuchi, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A projecting apparatus for forming an image of a mask on a wafer by a projector of a unit magnification reflection system having a concave spherical mirror and a convex spherical mirror. The distance from the projector to the mask or the upper side of a mask holder for holding the mask and the distance from the projector to the wafer are measured. An error of the image-forming position is computed from the distance measurements. At least one of the mask, the wafer and the projector is moved along the direction of projection in a manner to eliminate the error of the image-forming position computed, thus attaining automatic focus adjustment.