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:
Nov. 12, 2013
Filed:
Mar. 19, 2010
Tsuneo Uenaka, Yokkaichi, JP;
Kazuyuki Higashi, Yokohama, JP;
Tsuneo Uenaka, Yokkaichi, JP;
Kazuyuki Higashi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A memory string is formed to surround the side surface of a columnar portion and a charge storing layer, and includes plural first conductive layers functioning as gates of memory transistors, and a first protecting layer stacked to protect an upper portion of the plural first conductive layers. The plural first conductive layers constitute a first stairway portion formed stepwise such that their ends are located at different positions. Each first conductive layer constitutes a step of the first stairway portion. A top surface of a first portion of the first stairway portion is covered with the first protecting layer including a first number of layers, and A tope surface of a second portion of the first stairway portion located at a lower level than the first portion is covered with the first protecting layer including a second number of layers fewer than the first number of layers.