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. 21, 2014
Filed:
Mar. 15, 2012
Yoichiro Nishimoto, Tokyo, JP;
Nozomu Yasunaga, Tokyo, JP;
Takayoshi Matsuda, Tokyo, JP;
Mitsubishi Electric Corporation, Chiyoda-Ku, Tokyo, JP;
Abstract
A cleaning method of a silicon substrate includes a first step of etching a surface of a silicon substrate by a metal-ion-containing mixed aqueous solution of an oxidizing agent and hydrofluoric acid and of forming a porous layer on the surface of the silicon substrate, a second step of etching a pore of the porous layer by mixed acid mainly containing hydrofluoric acid and nitric acid and of forming texture on the surface of the silicon substrate, a third step of etching the surface of the silicon substrate on which the texture is formed with an alkaline chemical solution, and a fourth step of treating the silicon substrate etched by the alkaline chemical solution by ozone-containing water, of generating an air bubble within the pore formed in the silicon substrate, and of removing metal and organic impurities from within the pore.