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:
May. 21, 2002
Filed:
May. 14, 1999
Masato Kawata, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A non-volatile semiconductor memory manufacturing method, according to the present invention, is comprised of the process steps that follow. Device isolating layers are formed on predetermined places in a cell region. A layer of floating gate material is deposited next, all over the substrate. Either all the layer of floating electrode material, deposited on the device isolating layers or a part of it, is removed next, by etching, in order to form ditches. To fill the ditches, a first insulation layer is formed next, all over the cell region. A predetermined part of the first insulation layer is removed next, by etching, so the layer of floating electrode material is exposed. Thereafter, the ditches are filled in, on top of the device isolating oxide layers, with insulation layers. A second insulation layer is formed next, all over the cell region. Thereafter, electrode material layers and are deposited on the surface. The second insulation layer and the electrode material layers are all dry-etched, to form control electrodes in the cell region. Each part of the insulation layers is left on each of the device isolating oxide layers.