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:
Mar. 31, 1998
Filed:
Jul. 18, 1996
Robert F Allen, Gilbert, AZ (US);
Paul Holzapfel, Chandler, AZ (US);
Anthony L Bartels, Phoenix, AZ (US);
Warren Lin, Fremont, CA (US);
Speedfam Corporation, Chandler, AZ (US);
Abstract
An apparatus for detecting the presence of a workpiece on a polishing pad of a chemical mechanical polishing (CMP) machine employs an optical interrogation signal that is applied during the CMP process. An optical probe assembly produces a light signal that communicates with the polishing pad; portions of the light signal reflect from the polishing pad in a scattered manner. A light receptor receives reflected light associated with the interrogation signal, and the characteristics of the received light are analyzed and processed by a processor used by the apparatus. By analyzing the scattered light signals, the apparatus distinguishes the reflective characteristics of the polishing pad from the reflective characteristics of the workpiece. Thus, the apparatus is capable of detecting a lost or broken workpiece in a fast and effective manner.