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. 13, 2009
Filed:
Sep. 02, 2005
Sakae Koyata, Tokyo, JP;
Tomohiro Hashii, Tokyo, JP;
Katsuhiko Murayama, Tokyo, JP;
Kazushige Takaishi, Tokyo, JP;
Takeo Katoh, Tokyo, JP;
Sakae Koyata, Tokyo, JP;
Tomohiro Hashii, Tokyo, JP;
Katsuhiko Murayama, Tokyo, JP;
Kazushige Takaishi, Tokyo, JP;
Takeo Katoh, Tokyo, JP;
Sumco Corporation, Tokyo, JP;
Abstract
This silicon wafer production process comprises in the order indicated a planarization step, in which the front surface and the rear surface of a wafer are ground or lapped, a single-wafer acid etching step, in which an acid etching liquid is supplied to the surface of the wafer while spinning and the entire wafer surface is etched to control the surface roughness Ra to 0.20 μm or less, and a double-sided simultaneous polishing step, in which the front surface and the rear surface of the acid etched wafer are polished simultaneously. The process may comprise a single-sided polishing step, in which the top and bottom of the acid etched wafer are polished in turn, instead of the double-sided simultaneously polishing step.