Nonvolatile semiconductor storage device, and method for controlling nonvolatile semiconductor storage device
According to an aspect of the present invention, there is provided, a nonvolatile semiconductor storage device including: a substrate; a stacked portion that includes a plurality of conductor layers and a plurality of insulation layers alternately stacked on the substrate, at least one layer of the plurality of conductor layers and the plurality of insulation layers forming a marker layer; a charge accumulation film that is formed on an inner surface of a memory plug hole that is formed in the stacked portion from a top surface to a bottom surface thereof; and a semiconductor pillar that is formed inside the memory plug hole through the charge accumulation film.
1. A method for manufacturing a nonvolatile semiconductor storage device, the method comprising:
forming a lower stacked portion on a substrate, by alternately stacking a plurality of conductor layers and a plurality of insulation layers;
forming a marker layer on the lower stacked portion;
forming an upper stacked portion on the marked layer, by alternately stacking a plurality of conductor layers and a plurality of insulation layers;
forming a memory plug hole in the upper stacked portion by performing a first etching process;
further forming the memory plug hole in the marker layer by performing a second etching process;
further forming the memory plug in the lower stacked portion by performing a third etching process;
forming a charge accumulation film on an inner surface of the memory plug hole; and
forming a semiconductor pillar inside the memory plug hole through the charge accumulation film.
2. The method according to claim 1 ,
wherein the first etching process has an etching condition adjusted so that an etching rate for the upper stacked portion is higher than that for the marker layer.
3. The method according to claim 1 ,
wherein the second etching process has an etching condition adjusted so that an etching rate for the marker layer is higher than that for the lower stacked portion.
4. The method according to claim 1 ,
wherein the third etching process has an etching condition same as that of the first etching process.