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:
Jun. 11, 2002
Filed:
Jun. 15, 2000
Tokyo Seimitsu Co., Ltd., Mitaka, JP;
Abstract
The present invention provides a wafer polishing apparatus capable of controlling the polishing quantity accurately. The wafer polishing apparatus comprises a rotatable polishing stool with a polishing cloth, a carrier for bringing a wafer into contact with the polishing cloth under a predetermined pressure, a pad arranged around the wafer in such a manner as to contact the polishing cloth under a predetermined pressure, a detector for detecting the change of the relative positions of the back of the wafer or the carrier and the pad, and a control unit for controlling the polishing operation in accordance with the polishing quantity computed from the detection signal of the detector, wherein an operating unit includes a sampling unit ( ) for sampling the detection signal of the detector with such a sampling period that the number of times sampled per rotation of the polishing stool is plural, a moving average calculating unit ( ) for calculating the moving average data by averaging the sampling data in the number equal to an integer multiple of the number of times sampled per rotation, and a polishing quantity computing unit ( ) for computing the polishing quantity from the moving average data.