Patent ID: 7989880
Filing Date: 2011-08-02
Classification: H01L

Abstract:
1. A nonvolatile semiconductor memory device, comprising: a memory string having a plurality of electrically rewritable memory cells connected in series; and a wiring connected to a control electrode of the memory cells, the memory string comprising: a semiconductor layer including a columnar portion extending in a perpendicular direction with respect to a substrate; a charge storage layer formed on a side surface of the columnar portion; and a plurality of first conductive layers formed on the charge storage layer, and configured to function as a control electrode of the memory cells, the plurality of first conductive layers comprising a stepped portion formed in a stepped shape such that positions of ends of the plurality of first conductive layers differ from one another, and the wiring comprising a plurality of second conductive layers extending upwardly from an upper surface of the first conductive layers comprising the stepped portion, the plurality of second conductive layers being formed such that upper ends thereof are aligned with a surface parallel to the substrate, and such that a diameter thereof decreases from the upper end thereof to a lower end thereof, and the plurality of second conductive layers being formed such that the greater a length thereof in the perpendicular direction, the larger a diameter of the upper end thereof.