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:
Feb. 02, 1993
Filed:
Dec. 19, 1991
Masahiro Nakagawa, Yokohama, JP;
Hideo Mizutani, Yokohama, JP;
Kouichirou Komatsu, Tokyo, JP;
Yawara Nojima, Chiba, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A projection exposure apparatus comprises a projection optical system for forming an image of a predetermined pattern on a mask onto a photosensitive substrate under exposure light having a first wavelength, an illumination system for illuminating a mask on the photosensitive substrate with light having a second wavelength different from the first wavelength through the projection optical system so as to attain alignment, and a detection system for detecting light reflected by the mark. The illumination system comprises a light source for emitting the light having the second wavelength, a first field stop for defining an illumination field on the photosensitive substrate and a second field stop for defining an illumination field on the photosensitive substrate. The first field stop has at least two linear edges which extend in a direction substantially perpendicular to a sagittal direction in a visual field of the projection optical system and are juxtaposed in the sagittal direction at a predetermined interval. The second field stop extends in a direction substantially perpendicular to a meridional direction in a visual field of the projection optical system and has at least two linear edges juxtaposed in the meridional direction at a predetermined interval.