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:
Dec. 22, 1992
Filed:
Sep. 16, 1991
Akio Kawamura, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A method for forming a semiconductor device isolation region including steps of forming a first silicon oxide film on a silicon substrate, depositing a first silicon nitride film over the first silicon oxide film, and removing the first silicon oxide film and first silicon nitride film in a device isolation region by using a resist pattern, which is formed by a one-time photolithographic step, as a mask so as to expose the surface of the silicon substrate, removing the resist pattern, and oxidizing the exposed surface of the silicon substrate so as to form a second silicon oxide film having a smaller thickness than the first silicon oxide film and to deposit a second silicon nitride film, removing the second silicon nitride film by anisotropic etching until the second silicon oxide film is exposed in the device isolation region so as to make the second silicon nitride film remain as the side wall portion of the silicon nitride film in only the opening side wall portion of the first silicon nitride film, etching the second silicon oxide film in the opening of the first silicon nitride film on a self-aligning basis by using as etching masks the first silicon nitride film and the side wall portion of the second silicon nitride film remaining on the opening side wall portion of the first silicon nitride film, and selectively carrying out oxidation so as to form a thick silicon oxide film in the device isolation region.