Low deposition rates for flowable PECVD
PECVD methods for depositing a film at a low deposition rate comprising intermittent activation of the plasma are disclosed. The flowable film can be deposited using at least a polysilane precursor and a plasma gas. The deposition rate of the disclosed processes may be less than 500 Å/min.
1. A method comprising:
simultaneously exposing a substrate surface having at least one feature thereon to reactants comprising a polysilane precursor and a plasma gas; and
igniting the plasma gas at a regular interval to form a plasma and deposit a flowable film on the substrate surface within the at least one feature, the flowable film deposited at a rate of less than or equal to about 500 Å/min.
2. The method of claim 1 , wherein the flowable film is deposited at a rate of less than or equal to about 250 Å/min.
3. The method of claim 1 , wherein the regular interval has a duty cycle in a range of about 5% to about 90%.
4. The method of claim 3 , wherein the duty cycle is less than or equal to about 40%.
5. The method of claim 1 , wherein the polysilane precursor comprises one or more of disilane, trisilane, tetrasilane, neopentasilane or cyclohexasilane.
6. The method of claim 1 , wherein the plasma gas comprises one or more of He, Ar, Kr, H 2 , N 2 , O 2 , O 3 or NH 3 .
7. The method of claim 1 , wherein the plasma has a power less than or equal to about 200 W.
8. The method of claim 1 , wherein forming the flowable film occurs at a temperature of less than or equal to about 50° C.
9. The method of claim 1 , wherein the flowable film comprises one or more of SiN, SiO, SiC, SiOC, SiCN, SiON, or SiCON.
10. The method of claim 9 , wherein the reactants further comprise one or more of propylene, acetylene, ammonia, hydrazine, NO 2 , N 2 , N 2 O, O 2 , ozone or water.
11. The method of claim 1 , wherein the flowable film comprises a metal silicide.
12. The method of claim 11 , wherein the reactants further comprise one or more tungsten, tantalum and/or nickel precursors.
13. The method of claim 1 , wherein the flowable film consists essentially of silicon.
14. The method of claim 1 , further comprising curing the flowable film to form a substantially seam-free gapfill.
15. The method of claim 14 , wherein the gapfill has a hydrogen content of less than or equal to about 10 atomic percent.
16. A method comprising:
simultaneously exposing a substrate surface having at least one feature thereon to reactants comprising a polysilane precursor and a plasma gas;
igniting the plasma gas at a regular interval to form a plasma and deposit a flowable silicon-containing film on the substrate surface within the at least one feature, the regular interval having a duty cycle less than 40%, and the flowable silicon-containing film being deposited at a rate of less than or equal to about 500 Å/min; and
curing the flowable film to form a substantially seam-free gapfill.
17. The method of claim 16 , wherein the flowable silicon-containing film comprises one or more of Si, SiN, SiO, SiC, SiCN, SiOC, SiON, SiCON.
18. The method of claim 16 , wherein the plasma has a power less than or equal to about 200 W and a frequency in a range of about 10 Hz to about 10 kHz.
19. The method of claim 16 , wherein forming the flowable silicon-containing film occurs at a temperature of less than or equal to about 50° C. and a pressure in a range of about 1 Torr to about 10 Torr.
20. A method comprising:
simultaneously exposing a substrate surface having at least one feature thereon to reactants comprising a polysilane precursor and a plasma gas, the polysilane precursor comprising one or more of disilane, trisilane, tetrasilane, neopentasilane, or cyclohexasilane, the plasma gas comprising one or more of He, Ar, Kr, H 2 , N 2 , O 2 , O 3 or NH 3 ;
igniting the plasma gas at a regular interval to form a plasma and deposit a flowable film on the substrate surface within the at least one feature, the regular interval having a duty cycle less than 40%, the plasma having a power less than or equal to about 200 W, the film consisting essentially of silicon, the substrate surface being maintained at a temperature of less than or equal to about 50° C., and the flowable film being deposited at a rate of less than or equal to about 250 Å/min; and
curing the flowable film to form a substantially seam-free gapfill.