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:
Oct. 11, 1994
Filed:
Aug. 29, 1989
Alan R George, San Jose, CA (US);
John A Dahlquist, Palo Alto, CA (US);
Measurex Corporation, Cupertino, CA (US);
Abstract
A non-contact thickness measuring sensor is disclosed which determines the thickness of an overlying material on a substrate. The sensor includes two non-contact separation distance measuring devices which may be utilized to measure the distance from the first device to a portion of the interface between the substrate and the overlying material, while the second device determines the distance from the second device to a portion of the surface of the overlying layer. The difference in the measured distances is related to the thickness of the overlying material. In one embodiment, two lasers are used to measure the separation distances. In another embodiment, the two measured distances are coincident. Because of the coincident geometry of these two measurements, the thickness measuring sensor of this embodiment is substantially insensitive to misalignment of the sensor from the normal to the surface of the overlying layer being measured.