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:
Jan. 14, 1997
Filed:
Sep. 06, 1994
Tsukasa Ohoka, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A method of manufacturing a semiconductor device includes the following steps. A silicon oxide film having a predetermined film thickness is formed on a smooth major surface of a first silicon substrate of a first conductivity type having a first region wherein a power transistor is to be formed. The major surface of the first silicon substrate is bonded to a smooth major surface of a second silicon substrate having one of the first conductivity type and a second conductivity type. The other surface of the second silicon substrate bonded to the first silicon substrate is polished to form a silicon layer having a predetermined film thickness and a second region wherein a transistor constituting a control circuit for driving the power transistor is to be formed. The silicon layer and the silicon oxide film are removed from a predetermined portion in the first region. The power transistor of a vertical type is formed on the silicon substrate in the first region wherein the silicon layer and the silicon oxide film are selectively removed. The transistor constituting the control circuit is formed on the silicon layer on the silicon oxide film in the second region.