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:
Dec. 27, 1994
Filed:
Jan. 10, 1992
Atsushi Kitaoka, Ichikawa, JP;
Kenji Saitoh, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of aligning a mask and a wafer includes a step for providing the mask with first and second patterns each having an optical power and providing the wafer with first and second marks each having an optical power. A radiation beam irradiating the first pattern and the first mark produces a first beam, displaceable at a first magnification with a positional deviation of the wafer with respect to the mask, and irradiating the second pattern and the second mark produces a second beam, displaceable at a second magnification, larger than the first magnification, with a positional deviation of the wafer with respect to the mask. A first detecting step projects a radiation beam to the first mark and the first pattern to produce the first beam and detects a positional deviation of the wafer with respect to the mask based on the first beam. A first aligning step roughly aligns the wafer with the mask in accordance with the first detecting step. A second detecting step projects a radiation beam to the second pattern and the second mark to produce the second beam, and detects the residual positional deviation of the wafer and the mask based on the second beam. A second aligning step precisely aligns the mask and the wafer based on the second detecting step.