Nonvolatile semiconductor memory device and method of manufacturing the same

摘要

A nonvolatile semiconductor memory device comprises a memory string, and a wiring. The memory string comprises a semiconductor layer, a charge storage layer, and a plurality of first conductive layers. The plurality of first conductive layers comprises a stepped portion formed in a stepped shape such that positions of ends of the plurality of first conductive layers differ from one another. The wiring comprises 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 are 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. The plurality of second conductive layers are formed such that the greater a length thereof in the perpendicular direction, the larger a diameter of the upper end thereof.

主权项

1. A nonvolatile semiconductor memory device, comprising:
a memory cell region and a contact region, the memory cell region including memory strings, each of the memory strings including a plurality of electrically rewritable memory cells connected in series and extending in a first direction, the memory strings including a first memory string, a second memory string, and a third memory string, the first memory string and the second memory string being arranged along a second direction perpendicular to the first direction, the first memory string and the third memory string being arranged along a third direction perpendicular to the first direction and crossing the second direction, the contact region including conductive layers and insulating layers stacked alternately in a stacking direction, the conductive layers including a first conductive layer and a second conductive layer disposed above the first conductive layer, the contact region further including contact electrodes, each of the contact electrodes extending in the stacking direction, the contact electrodes including a first contact electrode and a second contact electrode, the first contact electrode being electrically connected to the first conductive layer and including a first cross-sectional area at a certain height level from a substrate, the second contact electrode being electrically connected to the second conductive layer and including a second cross-sectional area at the certain height level from the substrate, the first cross sectional area being larger than the second cross sectional area.