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. 31, 2004
Filed:
Sep. 12, 2002
Toshinari Nitta, Kyoto, JP;
Masatoshi Arai, Nara, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A first polysilicon film, an ONO film, and a second polysilicon film are deposited on a substrate. After ions of an impurity have been implanted in the second polysilicon film, a silicon oxide is deposited on the substrate, followed by a heat treatment for activating the impurity. Patterning is thereafter performed on the silicon oxide film, the second polysilicon film, the ONO film and the first polysilicon film to from stack cell electrodes and an on-gate protective film. The on-gate protective film formed of a silicon oxide film is densified to have improved resistance to etching. Therefore the desired shape of the on-gate protective film is maintained. The film thickness of sidewalls on side surfaces of the stack cell electrodes is set with stability, so that the reduction in insulation withstand voltage between a contact and a control gate electrode is limited.