Methods of filling trenches using high-density plasma deposition (HDP)
Methods of filling trenches/gaps defined by circuit elements on an integrated circuit substrate are provided. The methods include forming a first high-density plasma layer on an integrated circuit substrate including at least one trench thereon using a first reaction gas. The first high-density plasma layer is etched using an etch gas including nitrogen fluoride gas (NF 3 ). A second high-density plasma layer is formed on the etched first high-density plasma layer using a second reaction gas including nitrogen fluoride.
1. A method of filling trenches, the method comprising:
forming a first high-density plasma layer on an integrated circuit substrate including at least one trench thereon using a first reaction gas;
etching the first high-density plasma layer using an etch gas including nitrogen fluoride (NF 3 ) gas; and
forming a second high-density plasma layer on the etched first high-density plasma layer using a second reaction gas including nitrogen fluoride.
2. The method of claim 1 wherein the first reaction gas comprises oxygen (O 2 ), silane (SiH 4 ) and an inert gas and wherein the second reaction gas further comprises oxygen, silane and is free of an inert gas.
3. The method of claim 1 wherein forming the first high-density plasma layer comprises depositing the first high-density plasma oxide layer and wherein forming the second high-density plasma layer comprises depositing the second high-density plasma oxide layer.
4. The method of claim 3 wherein the first reaction gas comprises:
a silane gas having a flow rate of from about 10 to about 300 standard cubic centimeters per minute (SCCM);
an oxygen gas having a flow rate of from about 10 to about 300 SCCM; and
at least one of an argon (Ar) gas and a helium (He) gas having a flow rate of from about 0 to about 500 SCCM.
5. The method of claim 1 wherein the etch gas comprises:
an oxygen gas having a flow rate of from about 10 to about 300 standard cubic centimeters per minute (SCCM);
an argon (Ar) gas having a flow rate of from about 0 to about 500 SCCM; and
a nitrogen fluoride gas having a flow rate of from about 100 to about 500 SCCM.
6. The method of claim 5 wherein the etch gas further comprises hydrogen (H 2 ) gas.
7. The method of claim 1 wherein etching the first high-density plasma layer comprises etching the first high-density plasma layer using a chemical dry etching process.
8. The method of claim 1 wherein etching of the first high-density plasma layer comprises etching the first high-density plasma layer at a plasma power of from about 3000 to about 5000 Watts and a bias power of from about 0 to about 1500 Watts.
9. The method of claim 1 wherein forming of the second high-density plasma layer comprises depositing the second high-density plasma layer at a temperature of from about 650 to about 800° C.
10. The method of claim 1 wherein the second reactant gas comprises:
an oxygen gas having a flow rate of from about 10 to about 400 standard cubic centimeters per minute (SCCM);
a silane gas having a flow rate of from about 10 to about 400 SCCM; and
a nitrogen fluoride gas having a flow rate of from about 10 to about 300 SCCM.
11. The method of claim 10 wherein a flow-rate ratio of oxygen to silane is from about 1 to about 2.5.
12. The method of claim 10 wherein a flow-rate ratio of nitrogen fluoride to the second reaction gas (NF 3 /(NF 3 +SiH 4 +O 2 )) is from about 0.1 to about 0.5.
13. The method of claim of 1 wherein etching further comprises wet etching a portion of the first high-density plasma layer before forming the second high-density plasma layer.
14. The method of claim 13 wherein wet etching comprises wet etching the first high-density plasma layer using a nitrogen fluoride solution, a ammonium fluoride (NH 4 F) and hydrogen fluoride (HF) (LAL) solution and/or a buffered oxide etchant (BOE).
15. A method of filling trenches, the method comprising:
forming a first high-density plasma layer on an integrated circuit substrate including at least one trench thereon using a first reaction gas including oxygen (O 2 ) and silane (SiH 4 );
partially etching the first high-density plasma layer by chemically dry etching the first-high-density plasma layer using an etch gas including oxygen and nitrogen fluoride (NF 3 ); and
forming a second high-density plasma layer on the first high-density plasma layer using a second reaction gas including oxygen, silane and nitrogen fluoride at a temperature of from about 650 to about 800° C.
16. The method of claim 15 wherein the first reaction gas further comprises an inert gas and wherein the second reaction gas is free of an inert gas.
17. The method of claim 15 wherein forming the first high-density plasma layer comprises depositing the first high-density plasma oxide layer and wherein forming the second high-density plasma layer comprises depositing the second high-density plasma oxide layer.
18. The method of claim 17 wherein the first reaction gas comprises:
a silane gas having a flow rate of from about 10 to about 300 standard cubic centimeters per minute (SCCM);
an oxygen gas having a flow rate of from about 10 to about 300 SCCM; and
at least one of an argon (Ar) gas and a helium (He) gas having a flow rate of from about 0 to about 500 SCCM.
19. The method of claim 15 wherein the etch gas comprises:
an oxygen gas having a flow rate of from about 10 to about 300 standard cubic centimeters per minute (SCCM);
an argon (Ar) gas having a flow rate of from about 0 to about 500 SCCM; and
a nitrogen fluoride gas having a flow rate of 100 to 500 SCCM.
20. The method of claim 19 wherein the etch gas further comprises hydrogen (H2) gas.
21. The method of claim 15 wherein etching of the first high-density plasma layer further comprises etching the first high-density plasma layer at a plasma power of from about 3000 to about 5000 Watts and a bias power of from about 0 to about 1500 Watts.
22. The method of claim 15 wherein the second reactant gas comprises:
an oxygen gas having a flow rate of from about 10 to about 400 standard cubic centimeters per minute (SCCM);
a silane gas having a flow rate of from about 10 to about 400 SCCM; and
a nitrogen fluoride gas having a flow rate of from about 10 to about 300 SCCM.
23. The method of claim 22 wherein a flow-rate ratio of oxygen to silane is from about 1 to about 2.5.
24. The method of claim 22 wherein a flow-rate ratio of nitrogen fluoride to the second reaction gas (NF 3 /(NF 3 +SiH 4 +O 2 )) is from about 0.1 to about 0.5.
25. The method of claim of 15 wherein etching further comprises wet etching a portion of the first high-density plasma layer before forming the second high-density plasma layer.
26. The method of claim 25 wherein wet etching comprises wet etching the first high-density plasma layer using a nitrogen fluoride solution, a ammonium fluoride (NH 4 F) and hydrogen fluoride (HF) (LAL) solution and/or a buffered oxide etchant (BOE).