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:
Jul. 15, 1986
Filed:
Nov. 05, 1984
Mitsugu Yamamura, Yokohama, JP;
Minoru Yomoda, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An alignment apparatus for positioning on a wafer an image of a mask formed by a projection optical system. The apparatus includes a first detecting system for detecting the distance between an imaging plane of the optical system and the wafer, a driving mechanism for moving the wafer in the direction of the optical axis of the optical system and a second detecting system for detecting the amount of movement of the wafer. The driving mechanism is controlled while the distance detected by the first detecting system is compared with the amount of movement detected by the second detecting system, whereby the wafer is correctly and accurately positioned on the imaging plane of the optical system.