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:
Sep. 05, 1995
Filed:
Mar. 21, 1994
Tadahiro Kato, Fukushima, JP;
Sunao Shima, Fukushima, JP;
Masami Nakano, Fukushima, JP;
Hisashi Masumura, Fukushima, JP;
Hideo Kudo, Fukushima, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
A wafer which allows manufacture of a device to proceed at an exalted yield by preventing the resolution of exposure at the step of photolithography during the manufacture of the device from being impaired is obtained by a method which comprises a slicing step for slicing a single crystal ingot thereby obtaining wafers of the shape of a thin disc, a chamfering step for chamfering the wafer obtained by the slicing step, a lapping step for imparting a flat surface to the chamfered wafer, an etching step for removing mechanical strain remaining in the lapped wafer, an obverse surface-polishing step for polishing one side of the etched wafer, and a cleaning step for cleaning the polished wafer, which method is characterized by interposing between the etching step and the obverse surface-polishing step a reverse surface-preparing step for preparing the shape of the reverse side of the wafer.