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:
Aug. 10, 1999
Filed:
Sep. 17, 1997
Tsuneo Miyai, Tokyo, JP;
Yuji Imai, Omiya, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A focusing operation is performed so that the center of an exposure region on a photosensitive substrate coincides with a focal point of a projection optical system, based on setting information of a variable field stop, which sets the exposure region. Even in a case where only a portion of an exposable region of the projection optical system PL is set as the exposure region using the variable field stop, and only the set portion is subjected to exposure, exposure is performed while the set exposure region is brought into accurate focus, thereby improving resolution. Accordingly, an appropriate focusing operation can be always performed so as to achieve high accuracy exposure, irrespective of variations in the shape of the exposure region.