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. 11, 1984
Filed:
Sep. 17, 1982
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for processing a signal for aligning a mask having at least one standard mark thereon with a wafer having at least one reference mark thereon, includes a first sensor for sensing the standard mark, a second sensor for sensing the reference mark through the mask, a threshold value determining circuit for detecting a peak value from a signal stream put out by the first sensor and determining a first threshold value and for detecting a peak value from a signal stream put out by the second sensor and determining a second threshold value, a signal converting circuit for converting a signal of a higher level than the first threshold value from the signal stream put out by the first sensor into a first digital signal and for converting a signal of a higher level than the second threshold value from the signal stream put out by the second sensor into a second digital signal, and a composing circuit for composing the first digital signal and the second digital signal.