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. 06, 1992
Filed:
Apr. 22, 1991
Hitachi, Ltd., Tokyo, JP;
Abstract
A method and apparatus measures an image plane of a test pattern projected onto a surface of a sample disposed on a stage to precisely detect the image plane to thereby obtain a precise alignment therebetween for subsequent exposure. The test pattern is provided on a member having a conjugate surface with an upper surface of an illumination detecting unit having at least three optical sensors at different positions thereof and disposed on the stage. The upper surface of the illumination detecting unit has an analogous pattern to the test pattern on each optical sensor and, by moving the stage three dimensionally, outputs of the optical sensors are processed to obtain amounts of light and peak values thereof from which the image plane is obtained.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile