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:
Apr. 01, 1986
Filed:
Sep. 27, 1983
Yoshinori Makita, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of aligning a mask and a wafer for manufacturing semiconductor integrated circuits. The mask and wafer have respective alignment marks which are scanned by a laser beam to detect the misalignment therebetween. The relative position between the mask and wafer is changed in response to the detected misalignment. The marks are formed by bar-like mark elements. The width of the mark element, measured along the line of the beam scan, is 2 to 3 times the diameter of the scanning beam so that the light scattered by the leading edge of the mark element and the trailing edge of the mark element is separately detected by a photoelectric transducer, which produces a first signal in response to the leading edge and a second signal in response to the trailing edge. The position of the mark element is determined on the basis of the falling portion of the first signal and the rising portion of the second signal.