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:
Jun. 15, 1993
Filed:
Feb. 18, 1992
Yukihiro Saeki, Yokohama, JP;
Osamu Matsumoto, Kawasaki, JP;
Masayuki Yoshida, Kawasaki, JP;
Takahide Mizutani, Kawasaki, JP;
Nobuyoshi Chida, Kawasaki, JP;
Tomohisa Shigematsu, Yokohama, JP;
Teruo Uemura, Yokohama, JP;
Kenji Toyoda, Yokohama, JP;
Hiroyuki Takamura, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A manufacturing method of a semiconductor memory device includes the steps of selectively forming a field oxide film and a gate oxide film on a semiconductor substrate, depositing a first conductive layer on an entire surface of the resultant structure, selectively etching the first conductive layer located in a region other than an element region, depositing a second conductive layer on an entire surface of the resultant structure, and etching the first conductive layer and the second conductive layer using the same mask to form a plurality of floating gates by the first conductive layer and to form a plurality of control gates by the second conductive layer, wherein the step of selectively etching the first conductive layer includes the first etching step of forming cell slits for separating the plurality of floating gates from each other and the second etching step of forming removed regions each of which includes only one end of each of the plurality of control gates.