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:
Mar. 31, 1992
Filed:
Feb. 05, 1991
Applicant:
Inventors:
Nobuhisa Nakashima, Fukuoka, JP;
Tokumitsu Sakamoto, Fukuoka, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
437-7 ; 437-6 ; 437210 ; 437246 ; 437974 ; 437235 ;
Abstract
A silicon substrate (20) having a pnpn structure is soldered to a metal plate (10). A silicon oxide film (16) is naturally formed on the side surface of the silicon substrate during a process of removing defective part of the side surface, and a metal component penetrates into the silicon oxide film. The silicon substrate is dipped into an etchant to etch the silicon oxide film, so that a leak current through the metal component is effectively prevented.