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. 04, 2008
Filed:
Sep. 30, 2005
Toyokazu Sakata, Tokyo, JP;
Kousuke Hara, Tokyo, JP;
Toyokazu Sakata, Tokyo, JP;
Kousuke Hara, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
A method for manufacturing a semiconductor element includes preparing an SOI layer having a transistor forming area and an element isolation area, forming an oxidation-resistant mask layer on the SOI layer, forming a resist mask over the transistor forming area on the oxidation-resistant mask layer, a first etching that etches the oxidation-resistant mask layer using the resist mask so that a predetermined thickness of the oxidation-resistant mask layer remains, a second etching that etches the remaining oxidation-resistant mask layer, using the resist mask and exposing the SOI layer at the element isolation area, and oxidizing the exposed SOI layer using the remaining oxidation-resistant mask layer, to form an element isolation layer. An etching rate during the first etching is higher than during the second etching and a silicon-to-etching selection ratio during the second etching is higher than during the first etching.