Method of forming a bottle-shaped trench in a semiconductor substrate
AssigneeNanya Technology Corporation
InventorsYi-Nan Chen, Hsien-Wen Liu
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Abstract
A method of forming a bottle-shaped trench 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. An oxide film is then formed on the top portion of the trench. Next, the semiconductor substrate is etched through the bottom portion of the trench with a diluted ammonia solution as the etchant to form a bottle-shaped trench followed by removal of the oxide film.
Claims14
A method of forming a bottle-shaped trench in a semiconductor substrate, suitable for formation of a capacitor for 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 a 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 an 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) etching the semiconductor substrate through the bottom portion of the trench with a diluted ammonia solution as the etchant to form a bottle-shaped trench;
- and
- (j) 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 an oxide film on the top portion of the trench;
- etching the semiconductor substrate through the bottom portion of the trench with a diluted ammonia solution as the etchant to form a bottle-shaped trench;
- and
- removing the oxide film.
Dependencies are inferred from the claim text.