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:
Aug. 24, 1999
Filed:
Mar. 25, 1997
Tadahiro Kato, Nishigou-mura, JP;
Hisashi Masumura, Nishigou-mura, JP;
Sadayuki Okuni, Nishigou-mura, JP;
Hideo Kudo, Nishigou-mura, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
According to the invention, the flatness and quality can be improved while simplifying the process even when large size wafers of 200 to 300 mm or above are processed. Basic steps involved are a slicing step E for obtaining thin disc-shape wafers by slicing, a chamfering step F for chamfering the sliced wafers, a flattening step G for flattening the chamfered wafers, an alkali etching step H for removing process damage layers from the flattened wafers, and a double-side polishing step K of simultaneously polishing the two sides of the etched wafers. If necessary, a plasma etching step is used in lieu of the flattening and etching steps G and H respectively.