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:
Dec. 31, 2013
Filed:
Mar. 28, 2008
Tomokazu Matsuzaki, Kanagawa, JP;
Makoto Sasaki, Kanagawa, JP;
Masakuni Shimizu, Kanagawa, JP;
Renesas Electronics Corporation, Kawasaki-Shi, Kanagawa, JP;
Abstract
A method of manufacturing a semiconductor memory device which includes forming a conductive layer for a floating gate above a semiconductor layer intervening a gate insulating film therebetween, then, forming, over the conductive layer, a first spacer comprising a first silicon oxide material and a second spacer adjacent with the first spacer and comprising a second silicon oxide material, the second silicon oxide material having an etching rate lower than that of the first silicon oxide material, selectively removing the conductive layer by using the first and the second spacers as a mask, and removing the first spacer to expose a portion of the conductive layer. Since the etching rate for the second spacer is lower compared with the etching rate for the first spacer, the etching amount of the second spacer caused upon removal of the first spacer can be suppressed and, as a result, the productivity and the reliability of the semiconductor memory device can be improved.