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:
Oct. 25, 1988
Filed:
Apr. 14, 1986
Naoto Nakashima, Yokohama, JP;
Yoshitada Oshida, Fujisawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A reduction projection system alignment method for detecting the positions of an alignment pattern on a reticle and an alignment pattern on a wafer projected onto a reticle by a reduction projection lens so as to relatively align the reticle and wafer. This method comprises providing spatial images emanating from patterns on the reticle and wafer surfaces as alginment patterns of at least one of the reticle and wafer, and detecting the alignment patterns of the reticle and wafer by the same detection optical system using lights which are different in the wavelength from that of an exposure light and different from each other between the reticle and wafer. An apparatus for performing this method is also disclosed.