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. 21, 1995
Filed:
Sep. 01, 1993
Yuichi Kunori, Hyogo, JP;
Natsuo Ajika, Hyogo, JP;
Hiroshi Onoda, Hyogo, JP;
Makoto Ohi, Hyogo, JP;
Atsushi Fukumoto, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a semiconductor memory device according to the present invention, a conductive layer is formed on a field oxide film in a boundary region on the main surface of a semiconductor substrate. A floating gate electrode, an interlayer insulating film, and a control gate electrode are formed on the semiconductor substrate in a memory cell array region with a gate insulating film interposed therebetween. A gate electrode is formed in a peripheral circuit region with the gate insulating film interposed therebetween. An interlayer insulating film is formed on the conductive layer, the gate electrode, and the control gate electrode. A contact hole is formed at a predetermined position of the interlayer insulating film. An interconnection layer is selectively formed on the interlayer insulating film including the inner surface of the contact hole. According to the present invention, it is possible to prevent formation of a concave portion on the surface of the field oxide film in the boundary region. It is also possible to protect the memory cell array region from an external noise by forming the conductive layer on the field oxide film in the boundary region and by fixing the potential of the conductive layer.