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:
Oct. 03, 2000
Filed:
Jun. 06, 1995
Akiyoshi Suzuki, Tokyo, JP;
Miyoko Noguchi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An exposure apparatus for forming an image of a fine pattern having linear features extending in orthogonal first and second directions. The apparatus includes an illumination optical system for illuminating the pattern, the illumination optical system including a device for forming a secondary light source having decreased intensity portions at a center thereof and on first and second axes defined to intersect with each other at the center and defined along the first and second directions, respectively, wherein the secondary light source includes four sections being distributed in four quadrants defined by the center and the first and second axes, a projection optical system for projecting, on an image plane, an image of the pattern illuminated with light from the secondary light source, and a quartered detector, having four detector sections, for detecting a light quantity distribution of the secondary light source. Each of the four detector sections of the quartered detector independently detects a light quantity of a corresponding one of the four sections of the secondary light source.