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:
Sep. 30, 1997
Filed:
Jun. 06, 1995
Akiyoshi Suzuki, Tokyo, JP;
Miyoko Noguchi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An exposure apparatus for and a method of 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 includes a device for forming a secondary light source having decreased intensity portions at a center thereof and on first and second intersecting axes defined along the first and second directions, respectively. A projection optical system projects, on an image plane, an image of the pattern illuminated with light from the light source. The light source includes four sections having substantially the same intensity and being distributed in the four quadrants defined by the axes. An image of the light source is projected onto a pupil of the projection optical system. On the assumption of a coordinate system defined X and Y-axes extending along the first and second directions and intersecting at a center of the pupil, and that a radius of the pupil is one, coordinates of centers of the four sections are (p, p), (-p, p), (-p, -p) and (p, -p), wherein 0.25<p<0.6.