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:
Feb. 15, 1994
Filed:
Oct. 16, 1992
Takeo Muragishi, Hyogo, JP;
Eiichi Arima, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of making a non-volatile semiconductor memory device including a memory transistor of a dual gate structure in a memory cell adapted for storing memory information. A first gate insulating layer, a first electronically conductive layer and a second gate insulating layer are formed on the main surface of semiconductor substrate. An etching mask is formed on a third insulating layer formed on the semiconductor substrate. The third and second insulating layers are patterned by etching using a first etching technique while the conductive layer is patterned using a different etching technique to form a gate electrode narrower than the third insulating layer. Impurity ions are implanted diagonally into the main surface of the semiconductor substrate using the patterned third insulating layer at first gate electrode as masks.