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. 20, 1992
Filed:
Jul. 24, 1990
Masakazu Katoh, Furukawa, JP;
Takatoshi Ishikawa, Furukawa, JP;
Alps Electric Co., Ltd., Tokyo, JP;
Abstract
In the silicon substrate having porous oxidized silicon layers of this invention, which consists of a silicon substrate the one surface of which is dotted with porous oxidized silicon dots, the residual internal stress (compression stress) is dispersedly distributed in the porous oxidized silicon dots. Therefore, the entire silicon substrate having porous oxidized silicon dots of this invention is only minimally warped. Adopting a method for producing the silicon substrate of this invention which consists of covering with a mask the surface of a silicon substrate except its dotting areas to be treated, subjecting the silicon substrate to anodic formation in an aqueous hydrofluoric acid solution to form porous silicon layers in the areas to be treated and not covered with the mask and then oxidizing the formed porous silicon layers enables secured production of a silicon substrate provided with a plurality of polygonal shaped dots of porous oxidized silicon.