Method of forming a bottle-shaped trench in a semiconductor substrate
AssigneeNanya Technology Corporation
InventorsYi-Nan Chen, Hsien-Wen Liu, Hsin-Chuan Tsai
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Abstract
A method of forming a bottle-shaped trench in a semiconductor substrate. The method is suitable for formation of the capacitor of DRAM. First, the semiconductor substrate is selectively etched to form a trench, wherein the trench has a top portion and a bottom portion. A nitride film is then formed on the top portion of the trench. Next, the semiconductor substrate is etched through the bottom portion of the trench by a solution of hydrogen peroxide and hydrofluoric acid as the etchant to form a bottle-shaped trench followed by removal of the nitride film.
Claims18
A method of forming the 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 oxide 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 oxide film to leave the oxide 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 oxide film formed on the bottom portion of the trench;
- (g) forming a nitride film on the top portion of the trench;
- (h) removing the oxide 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 by a solution of hydrogen peroxide and hydrofluoric acid as the etchant to form the bottle-shaped trench;
- and
- (j) removing the nitride 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 nitride film on the top portion of the trench;
- etching the semiconductor substrate through the bottom portion of the trench by a solution of hydrogen peroxide and hydrofluoric acid as the etchant to form the bottle-shaped trench;
- forming a sacrificial oxide on the surface of the bottle-shaped trench by high density plasma chemical vapor deposition;
- and
- removing the sacrificial oxide and the nitride film by a solution containing hydrofluoric acid and ethylene glycol.
A method of forming a bottle-shaped trench in a semiconductor substrate, suitable for formation of the capacitor of DRAM, comprising the steps of:
- providing a trench having a top portion and a bottom portion in the semiconductor substrate;
- forming an oxide film on the surfaces of the trench;
- filling a shield material in the bottom portion of the trench;
- removing a part of the oxide film to leave the oxide film protected by the shield material and expose the surface of the semiconductor substrate at the top portion of the trench;
- removing the shield material to expose the oxide film formed on the bottom portion of the trench;
- forming a nitride film on the top portion of the trench;
- removing the oxide film to expose the surface of the semiconductor substrate at the bottom portion of the trench;
- and
- etching the semiconductor substrate through the bottom portion of the trench using a wet etchant to form the bottle-shaped trench.
Dependencies are inferred from the claim text.