Semiconductor memory device and manufacturing method thereof
A semiconductor memory device includes a first source layer, a second source layer on the first source layer, a stack structure over the second source layer, and a common source line penetrating the stack structure. The second source layer includes a protective layer in contact with the common source line and a conductive layer surrounding the protective layer.
1 . A method of manufacturing a semiconductor memory device, the method comprising:
forming a source structure including a source sacrificial structure;
forming a stack structure on the source structure;
forming a trench penetrating the stack structure;
forming a first cavity by removing the source sacrificial structure through the trench;
forming a preliminary conductive layer including a first preliminary conductive part in the trench and a second preliminary conductive part in the first cavity;
forming a first protective layer over the first preliminary conductive part and in a second cavity surrounded by the second preliminary conductive part;
removing a portion of the first protective layer in the trench and the second cavity to form a third cavity exposing a sidewall of the first protective layer in the second cavity; and
removing the first preliminary conductive part and a portion of the second preliminary conductive part to expand the third cavity.
2 . The method of claim 1 , wherein forming the first protective layer includes:
forming a first preliminary protective part in the trench; and
forming a second preliminary protective part in the first cavity.
3 . The method of claim 2 , wherein removing the portion of the first protective layer includes removing the first preliminary protective part.
4 . The method of claim 3 , wherein removing the first preliminary protective part includes forming an oxidation part by oxidizing the first preliminary protective part.
5 . The method of claim 4 , wherein removing the first preliminary protective part further includes removing the oxidation part.
6 . The method of claim 3 , wherein removing the first preliminary protective part includes etching the first preliminary protective part.
7 . The method of claim 1 , further comprising forming a channel structure penetrating the stack structure.
8 . The method of claim 7 , wherein the channel structure is formed to include a channel layer in contact with the second preliminary conductive part.
9 . A method of manufacturing a semiconductor memory device, the method comprising:
forming a source sacrificial structure;
alternately stacking insulating layers and gate sacrificial layers over the source sacrificial structure;
forming a trench penetrating the insulating layers and the gate sacrificial layers;
forming a first cavity by removing the source sacrificial structure through the trench;
forming a source layer including a conductive layer in the first cavity and a protective layer in a second cavity of the conductive layer;
forming a third cavity in the first cavity by removing a portion of the protective layer in the second cavity, wherein the third cavity is connected to the trench;
removing the gate sacrificial layers between the insulating layers, wherein the protective layer overlaps each area in which the gate sacrificial layers are removed;
forming gate patterns between the insulating layers; and
forming a common source line in the third cavity and the trench, wherein the common source line is coupled to the source layer.
10 . The method of claim 9 , wherein forming the source layer includes forming a preliminary conductive layer including the second cavity in the first cavity.
11 . The method of claim 10 , wherein forming the source layer further includes forming a preliminary protective layer in the second cavity.
12 . The method of claim 9 , further comprising forming a channel structure penetrating the source sacrificial structure, the insulating layers, and the gate sacrificial layers.
13 . The method of claim 9 , wherein forming the source layer includes:
forming a preliminary conductive layer including a first preliminary conductive part in the first cavity and a second preliminary conductive part in the trench; and
forming a preliminary protective layer in the preliminary conductive layer.
14 . The method of claim 13 , wherein forming the preliminary protective layer includes forming a first preliminary protective part in the first cavity and a second preliminary protective part in the trench.
15 . The method of claim 14 , wherein forming the source layer further includes removing the second preliminary protective part.
16 . The method of claim 15 , wherein removing the second preliminary protective part includes forming an oxidation part by oxidizing the second preliminary protective part.
17 . The method of claim 16 , wherein removing the second preliminary protective part further includes removing the oxidation part.
18 . The method of claim 15 , wherein removing the second preliminary protective part includes etching the second preliminary protective part.