Semiconductor memory device and manufacturing method of the semiconductor memory device
There are provided a semiconductor memory device and a manufacturing method of the semiconductor memory device. The semiconductor device includes: a first stack structure including interlayer insulating layers and first conductive patterns, which are alternately stacked; a second stack structure including a second conductive pattern overlapping with the first stack structure, and a third conductive pattern overlapping with the first stack structure with the second conductive pattern interposed between the first stack structure and the third conductive pattern, the third conductive pattern having an oxidation rate different from that of the second conductive pattern; channel structures penetrating the first stack structure and the second stack structure; and a bit line overlapping with the first stack structure with the second stack structure interposed between the first stack structure and the bit line.
1. A method of manufacturing a semiconductor memory device, the method comprising:
forming a first stack structure including interlayer insulating layers and sacrificial layers, which are alternately stacked;
forming a first conductive pattern overlapping the first stack structure;
forming a second conductive pattern overlapping with the first stack structure with the first conductive pattern interposed between the first stack structure and the second conductive pattern;
forming a hole penetrating the first stack structure, the first conductive pattern, and the second conductive pattern;
forming a multi-layer on a sidewall of the hole, wherein the multi-layer includes a first part extending along a sidewall of the first stack structure, a second part extending along a sidewall of the first conductive pattern, and a third part extending along a sidewall of the second conductive pattern, and a width of the second part is wider than that of each of the first part and the third part; and
forming a channel structure filling the hole on an inner wall of the multi-layer.
2. The method of claim 1 , wherein the second conductive pattern includes a conductive material having an oxidation rate lower than that of the first conductive pattern.
3. The method of claim 1 , wherein the first conductive pattern includes silicon, and the second conductive pattern includes a conductive material having a resistivity lower than that of the silicon.
4. The method of claim 1 , wherein the first conductive pattern includes silicon, and the second conductive pattern includes a tungsten silicide layer.
5. The method of claim 1 , wherein the first conductive pattern is formed thicker than each of the sacrificial layers, and
the second conductive pattern is formed thinner than the first conductive pattern.
6. The method of claim 1 , wherein the forming of the multi-layer includes:
forming a liner layer on a surface of the hole;
forming a blocking insulating layer by oxidizing the liner layer and the first conductive pattern by using an oxidation process in which an oxidation rate of the first conductive pattern is higher than oxidation rates of the liner layer and the second conductive pattern;
forming a data storage layer extending along an inner wall of the blocking insulating layer; and
forming a tunnel insulating layer extending along an inner wall of the data storage layer.
7. The method of claim 6 , wherein a portion of the blocking insulating layer, which extends along the sidewall of the first conductive pattern, is formed to have a width wider than portions of the blocking insulating layer, which extend along the sidewall of the first stack structure and the sidewall of the second conductive pattern, such that the inner wall of the blocking insulating layer has an uneven surface.
8. The method of claim 7 , wherein each of the data storage layer and the tunnel insulating layer extends along the uneven surface.
9. The method of claim 1 , wherein a central region of the hole includes a first central region surrounded by the first part of the multi-layer, a second central region surrounded by the second part of the multi-layer, and a third central region surrounded by the third part of the multi-layer, and
wherein the second part of the multi-layer further protrudes toward the second central region of the hole than the first part and the third part of the multi-layer such that the inner wall of the multi-layer has an uneven surface.
10. The method of claim 9 , wherein the forming of the channel structure includes:
forming a channel layer extending along the uneven surface;
filling the first central region and the second central region, which are opened by the channel layer, with a core insulating layer; and
filling the third central region opened by the channel layer with a doped semiconductor pattern.
11. The method of claim 10 , wherein a portion of a sidewall of the doped semiconductor pattern is surrounded by the second conductive pattern.
12. The method of claim 1 , further comprising:
forming a dummy hole penetrating the first stack structure, the first conductive pattern, and the second conductive pattern in the forming of the hole; and
forming a preliminary dummy channel structure in the dummy hole in the forming of the channel structure,
wherein the multi-layer extends onto a sidewall of the dummy hole.
13. The method of claim 12 , wherein the multi-layer includes a protrusion part protruding toward a central region of the dummy hole.
14. The method of claim 13 , further comprising forming a first slit penetrating the first conductive pattern and the second conductive pattern, the first slit isolating each of the first conductive pattern and the second conductive pattern into preliminary select lines,
wherein a portion of the preliminary dummy channel structure is removed, while the first slit is being formed.
15. The method of claim 1 , further comprising:
forming a second slit penetrating the first stack structure, the first conductive pattern, and the second conductive pattern; and
replacing the sacrificial layers with third conductive patterns through the second slit.