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:
Jul. 27, 1999
Filed:
Dec. 11, 1997
Kazuo Masaki, Kawasaki, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A projection exposure apparatus including a projection optical system for projecting a pattern formed in a reticle onto a photosensitive substrate, and an alignment system for positioning the reticle and the photosensitive substrate with respect to each other by observing a reticle mark alignment formed on the reticle and a substrate alignment mark formed on the photosensitive substrate; wherein the alignment system comprises an imaging section having an imaging surface tilted with respect to an optical axis of the alignment system and with respect to a direction orthogonal to a measuring direction for each of the alignment marks, the imaging section having respective best focus positions for the alignment marks at different positions on the imaging surface; and wherein the alignment marks are simultaneously detected at the respective best focus positions so as to position the reticle and the photosensitive substrate with respect to each other. The best focus positions are determined by the focus detecting section within the image processing system according to image signals obtained from the imaging section.