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. 17, 1992
Filed:
Feb. 11, 1991
Akio Kawamura, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A method for forming semiconductor device isolation regions including steps of forming a first insulating film on a semiconductor substrate, removing the first insulating film in a portion to become a device isolation region with use of a resist pattern formed in a one-time lithography step as a mask so as to form an opening which reaches the semiconductor substrate, removing the resist pattern to deposit a second insulating film on the first insulating film and the inside of the opening and then etching the entire surface in order to make the second insulating film remain on only the periphery of the bottom of the opening and to expose the surface of the semiconductor substrate in a central portion of the bottom of the opening, forming an oxide film on the surface of the semiconductor substrate exposed in the central portion of the bottom of the opening with use of the first insulating film and the second insulating film on the periphery of the bottom of the opening as a mask by a selective oxidation method, removing the second insulating film on the periphery of the bottom of the opening and then etching the surface of the semiconductor substrate exposed on the periphery of the bottom of the opening with use of the oxide film formed in the central portion of the bottom of the opening by the selective oxidation method and the first insulating film which remains in portions other than the device isolation region as a mask so as to form a trench, and burying the trench with a third insulating film.