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:
May. 10, 1994
Filed:
Jun. 01, 1993
Koichi Matsumoto, Tokyo, JP;
Kazuo Ushida, Tokyo, JP;
Masaomi Kameyama, Tokyo, JP;
Hiroyuki Tsuchiya, Konosu, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A projection exposure apparatus is provided with an illumination optical system for illuminating a reticle having a predetermined pattern and a projection optical system having a predetermined numerical aperture for projecting the predetermined pattern of the reticle illuminated by the illumination optical system onto a wafer surface. The projection optical system is arranged so that, with respect to the focusing of an image of the reticle onto the wafer surface, spherical aberration, which depends on the numerical aperture of the projection optical system, shows a positive tendency corresponding to overcorrection in third-order spherical aberration and a negative tendency corresponding to undercorrection in fifth-order spherical aberration.