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. 07, 1999
Filed:
Apr. 24, 1996
Minekazu Sakai, Kariya, JP;
Tsuyoshi Fukada, Aichi-gun, JP;
Koki Mizuno, Okazaki, JP;
Yasutoshi Suzuki, Okazaki, JP;
Yoshitsugu Abe, Anjo, JP;
Hiroshi Tanaka, Toyokawa, JP;
Motoki Ito, Nagoya, JP;
Kazuhisa Ikeda, Chiryu, JP;
Hiroshi Okada, Nukata-gun, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
An etching method for a silicon substrate, which can easily smooth the etching surface of the (110)-oriented silicon, is disclosed. A container is filled with KOH solution. In the KOH solution is immersed a (110)-oriented silicon wafer having a PN junction and is also disposed a platinum electrode plate to face the silicon wafer. To between a platinum electrode of the silicon wafer and the platinum electrode plate are connected a constant voltage power source, an ammeter and a contact in series. A controller starts etching from one surface on which the PN junction is formed, and terminates voltage application when the specified time lapses after the formation of an anodic oxide film is equilibrated with the etching of the anodic oxide film on the etching surface on the PN junction part. In this case, the controller detects flowing current through the ammeter, and the point of time when the equilibrium state is obtained is the point of inflection of the detected current to the constant current after the peak thereof.