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:
Aug. 16, 2005
Filed:
Mar. 05, 2003
Masahiro Hayashi, Sakata, JP;
Masahiro Hayashi, Sakata, JP;
Seiko Epson Corporation, , JP;
Abstract
A method is provided for manufacturing a semiconductor device having a high breakdown voltage transistor and a low breakdown voltage transistor with different driving voltages in a common substrate. The method includes: (a) introducing an impurity of a second conductivity type in a specified region of a semiconductor substrate of a first conductivity type to form a first impurity layer and a second impurity layer; (b) further introducing an impurity of the second conductivity type in a region of the second impurity layer to form a third impurity layer; and (c) conducting a heat treatment to diffuse impurities of the first impurity layer and the third impurity layer to form a first well of the second conductivity type and a second well of the second conductivity type having an impurity concentration higher than the first well.