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:
Sep. 18, 1990
Filed:
Mar. 07, 1989
Applicant:
Inventors:
Noel S Poduje, Needham Heights, MA (US);
Roy E Mallory, Bedford, MA (US);
Assignee:
ADE Corporation, Bedford, MA (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R / ;
U.S. Cl.
CPC ...
324661 ; 324690 ;
Abstract
An edge detection system for measuring lateral position in the presence of height variations such as found in gauging the edge position of a wafer uses first and second capacitive probes formed of passive elements with the active components kept outside the probe and at a distance that permits a smaller, stabler and more economical probe to be located at the location of the wafer. The probes are instrumented in an electronic circuit having plural operational amplifiers that drive the probes to compensate the edge detection for wafer height effects.