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:
Nov. 10, 2009
Filed:
Mar. 13, 2008
Susumu Onishi, Nagano, JP;
Masashi Maruta, Nagano, JP;
Susumu Onishi, Nagano, JP;
Masashi Maruta, Nagano, JP;
Fujikoshi Machinery Corp., Nagano-Shi, JP;
Abstract
The double-side polishing apparatus for polishing both faces of a wafer is capable of reliably measuring not only a thickness of an outer part of the wafer but also a thickness of a center part thereof. The double-side polishing apparatus comprises: a lower polishing plate; an upper polishing plate held by a frame; and a carrier having a through-hole for holding the wafer. A window section, through which a laser beam passes, is formed in a part of the upper polishing plate, under which the wafer held by the carrier passes. An optical thickness measuring equipment is provided to a part of the frame, under which the window section passes while the upper polishing plate is rotated. The thickness measuring equipment emits the laser beam through the window section, receives reflected beams reflected from an upper face and a lower face of the wafer, and calculates the thickness of the wafer on the basis of peak values of the reflected beams.