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. 01, 1983
Filed:
Apr. 04, 1983
Susumu Sakaguchi, Annaka, JP;
Kenichi Taguchi, Joetsu, JP;
Masaaki Iguchi, Annaka, JP;
Kunihiro Ito, Annaka, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
The invention provides a method for surface-finishing of a single crystal wafer of a ferroelectric material into a substrate plate suitable for use, for example, as a SAW filter element which is mirror-polished only on one of the surfaces, the other surface having an adequate roughness. Different from conventional methods, the inventive method comprises the successive steps of (a) slicing a single crystal boule into wafers, (b) lapping of the wafer on both surfaces to impart adequate roughness to the surfaces, (c) chemically etching the thus lapped surfaces to remove the strain produced in the preceding mechanical working, and (d) mirror-polishing one of the thus etched surfaces so that high uniformity of the thickness and greatly decreased warping of the wafer can be ensured.