Method of forming a bottle-shaped trench in a semiconductor substrate
AssigneeNanya Technology Corporation
InventorsYi-Nan Chen, Tung-Wang Huang, Hsin-Jung Ho, Hsien-Wen Liu
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Abstract
A method of forming a bottle-shaped trench for capacitor in a semiconductor substrate. First, the semiconductor substrate is selectively etched to form a trench, wherein the trench has a top portion and a bottom portion. Then, an oxide film is formed on the top portion of the trench. Next, a rugged polysilicon layer is formed on the bottom portion and the top portion of the trench. The rugged polysilicon layer and the semiconductor substrate are etched through the bottom portion of the trench by diluted ammonia solution as the etchant to form a bottle-shaped trench having a rugged surface. Next, the oxide film is removed.
Claims18
A method of forming a bottle-shaped trench in a semiconductor substrate, suitable for formation of the capacitor of DRAM, comprising the steps of:
- (a) forming a hard mask having an opening on the semiconductor substrate;
- (b) etching the semiconductor substrate through the opening of the hard mask to create a trench, wherein the trench has a top portion and a bottom portion;
- (c) forming an nitride film on the surfaces of the trench and the hard mask;
- (d) filling a shield material in the bottom portion of the trench;
- (e) removing a part of the nitride film to leave the nitride film protected by the shield material and expose the surface of the semiconductor substrate at the top portion of the trench;
- (f) removing the shield material to expose the nitride film formed on the bottom portion of the trench;
- (g) forming a oxide film on the top portion of the trench;
- (h) removing the nitride film to expose the surface of the semiconductor substrate at the bottom portion of the trench;
- (i) forming a rugged polysilicon layer on the exposed surface of the semiconductor substrate at the bottom portion of the trench;
- (j) etching the rugged polysilicon layer and the semiconductor substrate through the bottom portion of the trench by a diluted ammonia solution as the etchant to form a bottle-shaped trench having a rugged surface;
- and
- (k) removing the oxide film.
A method of forming a bottle-shaped trench in a semiconductor substrate, suitable for formation of the capacitor of DRAM, comprising the steps of:
- selectively etching the semiconductor substrate to form a trench, wherein the trench has a top portion and a bottom portion;
- forming a oxide film on the top portion of the trench;
- forming a rugged polysilicon layer on the bottom portion and the top portion of the trench;
- etching the rugged polysilicon layer and the semiconductor substrate through the bottom portion of the trench by diluted ammonia solution as the etchant to form a bottle-shaped trench;
- and
- removing the oxide film.
Dependencies are inferred from the claim text.