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:
Feb. 08, 1993
Kazuya Kamon, Itami, JP;
Teruo Miyamoto, Amagasaki, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A projection exposure apparatus includes a light source, a condenser lens for illuminating an illumination light emanating from the light source onto a mask on which a circuit pattern has been formed, a projection lens for condensing the illumination light which has passed through the mask onto a surface of a wafer, and an aperture member disposed between the light source and the condenser lens and having both a transmission area for shaping the light emanating from the light source and a light blocking area formed at a central portion of the transmission area. An outer diameter of the transmission area of the aperture member is set such that a ratio .sigma. of an outer diameter of an effective light source to a diameter of a pupil of the projection lens is 0.6.+-.0.3, while a light blocking rate of the light blocking area is set to 60.+-.35%.