Flowable film curing using H2 plasma
Embodiments herein provide methods of plasma treating an amorphous silicon layer deposited using a flowable chemical vapor deposition (FCVD) process. In one embodiment, a method of processing a substrate includes plasma treating an amorphous silicon layer by flowing a substantially silicon-free hydrogen treatment gas into a processing volume of a processing chamber, the processing volume having the substrate disposed on a substrate support therein, forming a treatment plasma of the substantially silicon-free hydrogen treatment gas, and exposing the substrate having the amorphous silicon layer deposited on a surface thereof to the treatment plasma. Herein, the amorphous silicon layer is deposited using an FCVD process. The FCVD process includes positioning the substrate on the substrate support, flowing a processing gas into the processing volume, forming a deposition plasma of the processing gas, exposing the surface of the substrate to the deposition plasma, and depositing the amorphous silicon layer on the surface of the substrate.
1. A method of processing a substrate, comprising:
depositing an amorphous silicon layer on the surface of the substrate using a flowable chemical vapor deposition (FCVD) process, comprising:
positioning a substrate on a substrate support disposed in a processing volume of a processing chamber;
flowing a processing gas into the processing volume;
forming a deposition plasma of the processing gas;
exposing the surface of the substrate to the deposition plasma; and
depositing the amorphous silicon layer on the surface of the substrate; then
purging the processing volume, comprising:
stopping the flow of the processing gas;
extinguishing the deposition plasma; and then
plasma treating the amorphous silicon layer, comprising:
flowing a substantially silicon-free hydrogen treatment gas into a processing volume;
forming a treatment plasma of the substantially silicon-free hydrogen treatment gas by capacitively coupling the treatment gas with an electrode at an RF power between about 100 W and about 500 W;
exposing the amorphous silicon layer to the treatment plasma; and
maintaining the substrate at a temperature between about −100° C. and about 100° C. during the exposing the amorphous silicon layer to the treatment plasma.
2. The method of claim 1 , wherein the treatment plasma is formed by capacitively coupling the substantially silicon-free treatment gas with an electrode at an RF power between about 0.10 W/cm 2 of substrate surface area and about 1 W/ cm 2 .
3. The method of claim 1 , wherein plasma treating the amorphous silicon layer comprises maintaining the processing volume at a pressure between about 1 mTorr and about 2 Torr.
4. The method of claim 1 , wherein the hydrogen treatment gas is substantially silicon-free and substantially oxygen-free.
5. The method of claim 1 , wherein the substantially silicon-free hydrogen treatment gas comprises H 2 and an inert gas.
6. The method of claim 5 , wherein a ratio of H 2 to inert gas is between about 1:10 and about 5:1.
7. The method of claim 5 wherein the inert gas is Ar.
8. The method of claim 1 , wherein plasma treating the amorphous silicon layer comprises exposing the substrate to the treatment plasma for more than about 10 seconds.
9. The method of claim 1 , wherein the processing gas comprises one or more silicon precursors selected from the group consisting of silane (SiH 4 ), disilane (Si 2 H 6 ), trisilane (Si 3 H 8 ), and tetrasilane (Si 4 H 10 ), neopentasilane (NPS), and cyclohexasilanes.
10. The method of claim 9 , wherein the processing gas is one or both of substantially nitrogen-free and substantially oxygen-free.
11. The method of claim 1 , wherein the plasma treated amorphous silicon layer has a refractive index of not less than about 4.1.
12. The method of claim 1 , further comprising a plurality of sequential cycles of depositing the amorphous silicon layer and plasma treating the amorphous silicon layer.
13. A method of processing a substrate, comprising:
depositing an amorphous silicon layer, comprising:
positioning the substrate on a substrate support disposed in a processing volume;
flowing a processing gas into the processing volume, wherein the processing gas is substantially oxygen-free and substantially nitrogen-free;
forming a deposition plasma of the processing gas by capacitively coupling the processing gas with an electrode at an RF or other ac frequency power of less than about 300 W;
exposing the surface of the substrate to the deposition plasma; and
depositing the amorphous silicon layer on a surface of the substrate; then
purging the processing volume, comprising:
stopping the flow of the processing gas;
extinguishing the deposition plasma;
flowing a purge gas into the processing volume; and
evacuating the purge gas from the processing volume before plasma treating the amorphous silicon layer; and then plasma treating the amorphous silicon layer, comprising:
flowing a treatment gas into the processing volume, wherein the treatment gas comprises H 2 and an inert gas in a ratio between about 1:10 and about 5:1, and wherein the treatment gas is substantially silicon-free and substantially oxygen-free;
forming a treatment plasma of the treatment gas by capacitively coupling the treatment gas with an electrode at an RF power between about 100 W and about 500 W;
exposing the amorphous silicon layer to the treatment plasma for a duration of more than about 10 seconds; and
maintaining the substrate at a temperature between about −100° C. and about 100° C. during the exposing the amorphous silicon layer to the treatment plasma.
14. The method of claim 13 , wherein depositing the amorphous silicon layer further comprises maintaining the processing volume at a pressure between about 10 mTorr and about 10 Torr.
15. The method of claim 13 , wherein the plasma treated amorphous silicon layer has a refractive index of not less than about 4.1.
16. The method of claim 13 , further comprising a plurality of sequential cycles of depositing the amorphous silicon layer and plasma treating the amorphous silicon layer.
17. The method of claim 16 , wherein forming the deposition plasma comprises applying an RF or other ac frequency power of less than about 300 W to a showerhead disposed in the processing volume.
18. A method of processing a substrate, comprising:
depositing an amorphous silicon layer, comprising:
positioning a substrate on a substrate support disposed in a processing volume;
flowing a processing gas into the processing volume, wherein the processing gas is substantially oxygen-free and substantially nitrogen-free;
forming a deposition plasma of the processing gas by capacitively coupling the processing gas with an electrode at an RF or other ac frequency power of less than about 300 W;
exposing the surface of the substrate to the deposition plasma; and
depositing the amorphous silicon layer on a surface of the substrate; then
purging the processing volume, comprising:
stopping the flow of the processing gas;
extinguishing the deposition plasma;
flowing a purge gas into the processing volume; and
evacuating the purge gas from the processing volume before plasma treating the amorphous silicon layer; and then
plasma treating the amorphous silicon layer, comprising:
flowing a treatment gas into the processing volume, wherein the treatment gas comprises H 2 and an inert gas in a ratio between about 1:10 and about 5:1, and wherein the treatment gas is substantially silicon-free and substantially oxygen-free;
forming a treatment plasma of the treatment gas by capacitively coupling to an electrode at an RF or other ac frequency power between about 100 W and about 500 W;
exposing the amorphous silicon layer to the treatment plasma for a duration of more than about 10 seconds; and then
maintaining the substrate at a temperature between about −100° C. and about 100° C. during the exposing the amorphous silicon layer to the treatment plasma.
19. The method of claim 18 , wherein the plasma treated amorphous silicon layer has a refractive index of not less than about 4.1.