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:
Jul. 23, 1996
Filed:
Jan. 06, 1995
Shigeyoshi Netsu, Darul Ehsan, MY;
Kihachiro Watanabe, Fukushima-ken, JP;
Makoto Tsukada, Saitama-ken, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
An elastic foamed sheet is disclosed which is usable as waxless polishing backing pads for wafers and capable of producing mirror polish wafers excelling in flatness. This elastic foamed sheet possesses at least a foamed layer 2 and is characterized by the fact that a plurality of bubbles 4 in the foamed layer 2 meet the following conditions: (1) that the bubbles are slender discrete bubbles erected parallelly to one another and dispersed at a substantially equal pitch in the direction of width of the foamed layer 2 and the bubbles 4 are substantially equal in size, shape, and position of formation in the direction of thickness of the foamed layer 2, (2) that center lines of the bubbles 4 in the direction of length thereof are parallel to the direction of thickness of the foamed layer 2, and (3) that the diameters of the bubbles 4 are minimized in the terminal part of the foamed layer 2 on one surface side thereof and gradually increased in the direction from the one surface side to the other surface side of foamed layer 2 until the bubbles form openings 6 thereof in the surface of the foamed layer 2.