Semiconductor device manufacturing method including exposing electrode layers into a hole

1. A semiconductor device manufacturing method comprising:

alternately stacking a plurality of insulating layers and electrode layers;

forming a hole penetrating through a multilayer body of the insulating layers and the electrode layers;

forming a conductive film on an inner wall of the hole;

anisotropically etching the conductive film to selectively leave the conductive film on a sidewall of the hole;

altering the conductive film into an insulator by heat treatment; and

removing the insulator covering the electrode layers to expose the electrode layers into the hole.

2. The method according to claim 1 , wherein the conductive film is altered into the insulator by thermal oxidation.

3. The method according to claim 1 , wherein the electrode layers and the conductive film are made of the same material.

4. The method according to claim 3 , wherein the electrode layers and the conductive film contain silicon.

5. The method according to claim 1 , wherein the insulating layers are silicon oxide layers.

6. The method according to claim 1 , wherein the conductive film at bottom of the hole is removed by the anisotropic etching.

7. The method according to claim 1 , wherein a thickness of the conductive film left on the sidewall of the hole is relatively thinner on a lower portion of the hole than on an upper portion of the hole.

8. The method according to claim 2 , wherein by the heat treatment, oxidation is advanced by at least a thickness of the conductive film.

9. The method according to claim 2 , wherein the thermal oxidation is advanced also toward the electrode layers in a portion of the conductive film opposed to the electrode layers.

10. The method according to claim 2 , wherein the thermal oxidation forms a thermally oxidized portion expanded in volume into the hole relative to the conductive film.

11. The method according to claim 1 , wherein the insulator is removed by etching.

12. The method according to claim 11 , wherein in the etching for removing the insulator, the insulating layers are overetched in a direction expanding the hole relative to end surfaces of the electrode layers exposed into the hole.

13. The method according to claim 1 , further comprising:

after exposing the electrode layers into the hole, forming an insulating film including a charge storage layer on the sidewall of the hole; and

forming a semiconductor layer inside the insulating film in the hole.

14. The method according to claim 13 , wherein the forming the insulating film includes:

forming a first silicon oxide film on the sidewall of the hole;

forming a silicon nitride film as the charge storage layer inside the first silicon oxide film; and

forming a second silicon oxide film inside the silicon nitride film.

15. A semiconductor device manufacturing method comprising:

forming a recess in a conductive layer;

burying a sacrificial film in the recess;

alternately stacking a plurality of insulating layers and electrode layers on the conductive layer having the sacrificial film buried therein;

forming a hole penetrating through a multilayer body of the insulating layers and the electrode layers;

forming a conductive film on an inner wall of the hole;

anisotropically etching the conductive film to selectively leave the conductive film on a sidewall of the hole;

altering the conductive film into an insulator by heat treatment;

removing the insulator covering the electrode layers to expose the electrode layers into the hole; and

removing the sacrificial film in the recess through the hole to connect the hole exposing the electrode layers to the recess.