Low temperature plasma enhanced chemical vapor deposition of conformal silicon carbon nitride and silicon nitride films
Methods and apparatus for forming conformal silicon nitride films at low temperatures on a substrate are provided. The methods of forming a silicon nitride layer include performing a deposition cycle including flowing a processing gas mixture into a processing chamber having a substrate therein, wherein the processing gas mixture comprises precursor gas molecules having labile silicon to nitrogen, silicon to carbon, or nitrogen to carbon bonds, activating the precursor gas at a temperature between about 20° C. to about 480° C. by preferentially breaking labile bonds to provide one or more reaction sites along a precursor gas molecule, forming a precursor material layer on the substrate, wherein the activated precursor gas molecules bond with a surface on the substrate at the one or more reaction sites, and performing a plasma treatment process on the precursor material layer to form a conformal silicon nitride layer.
1. A method of forming a silicon nitride layer, comprising:
performing a deposition cycle, comprising:
flowing a processing gas mixture into a processing chamber having a substrate therein, wherein the processing gas mixture comprises precursor gas molecules having labile silicon to nitrogen, silicon to carbon, or nitrogen to carbon bonds;
activating the precursor gas at a temperature between about 20° C. to about 480° C. by preferentially breaking labile bonds to provide one or more reaction sites along a precursor gas molecule;
forming a precursor material layer on the substrate, wherein the activated precursor gas molecules bond with a surface on the substrate at the one or more reaction sites; and
performing a plasma treatment process on the precursor material layer to form a conformal silicon nitride layer.
2. The method of claim 1 , wherein activating the precursor gas further comprises:
generating a plasma in the processing chamber at an RF power density from about 0.01 W/cm 2 to about 40 W/cm 2 .
3. The method of claim 2 , wherein the temperature is less than 300° C.
4. The method of claim 1 , wherein the precursor gas is selected from the group consisting of substituted silazanes, substituted silanes, or combinations thereof.
5. The method of claim 4 , wherein the substituted silazanes comprises tetramethylcyclotetrasilazanes, hexamethylcyclotetrasilazanes (HMCTZ), octamethylcyclotetrasilazanes, hexamethyldisilazane (HMDS), or combinations thereof.
6. The method of claim 4 , wherein the substituted silanes comprises bis-diethylamine silane (BDEAS), bis(tertiary-butylamino)silane (BTBAS), tris(dimethylamino)silane (TDMAS), or combinations thereof.
7. The method of claim 1 , wherein the plasma treatment process cross-links the precursor gas compounds in the precursor material layer.
8. The method of claim 1 , wherein the deposition cycle is repeated from 1 to 120 times.
9. The method of claim 1 , wherein the processing gas mixture further comprises ammonia (NH 3 ), hydrazine (N 2 H 4 ), helium (He), argon (Ar), xenon (Xe), hydrogen (H 2 ), nitrogen (N 2 ), or combinations thereof.
10. The method of claim 1 , wherein the performing the plasma treatment process comprises:
stopping the flow of the precursor gas molecules; and
flowing a plasma treatment gas into the processing chamber, wherein the plasma treatment gas comprises ammonia (NH 3 ), hydrazine (N 2 H 4 ), helium (He), argon (Ar), xenon (Xe), hydrogen (H 2 ), nitrogen (N 2 ), or combinations thereof.
11. The method of claim 10 , wherein the conformal silicon nitride layer is doped with carbon.
12. The method of claim 11 , wherein controlling the duration of the plasma treatment process controls the amount of carbon in the silicon nitride layer.
13. The method of claim 1 , further comprising:
performing a UV cure process on the conformal silicon nitride layer without exposing the silicon nitride layer to oxygen.
14. The method of claim 1 , wherein the conformal silicon nitride layer has a conformality of 90% or greater.
15. A method of forming a silicon nitride layer, comprising:
performing a deposition cycle, comprising:
flowing a processing gas mixture into a processing chamber having a substrate therein, wherein the processing gas mixture comprises precursor gas molecules having labile silicon to nitrogen, silicon to carbon, or nitrogen to carbon bonds;
generating a plasma in the processing chamber at an RF power density from about 0.01 W/cm 2 to about 40 W/cm 2 and at a temperature between about 20° C. to about 480° C. to activate the precursor gas by preferentially breaking labile bonds to provide one or more reaction sites along a precursor gas molecule;
forming a precursor material layer on the substrate, wherein the activated precursor gas molecules bond with a surface on the substrate at the one or more reaction sites; and
performing a plasma treatment process on the precursor material layer to form a conformal silicon nitride layer and control the amount of carbon in the conformal silicon nitride film composition, wherein performing the plasma treatment process comprises:
stopping the flow of the precursor gas molecules; and
flowing a plasma treatment gas into the processing chamber, wherein the plasma treatment gas comprises ammonia (NH 3 ), hydrazine (N 2 H 4 ), helium (He), argon (Ar), xenon (Xe), hydrogen (H 2 ), nitrogen (N 2 ), or combinations thereof; and
repeating the deposition cycle from 1 to 120 times.
16. The method of claim 15 , wherein activating the precursor gas provides a single reaction site along the precursor gas molecule.
17. The method of claim 15 , wherein the precursor gas is selected from the group consisting of tetramethylcyclotetrasilazanes, hexamethylcyclotetrasilazanes (HMCTZ), octamethylcyclotetrasilazanes, hexamethyldisilazane (HMDS), bis-diethylamine silane (BDEAS), bis(tertiary-butylamino)silane (BTBAS), tris(dimethylamino)silane (TDMAS), or combinations thereof.
18. A method of forming a silicon nitride layer, comprising:
performing a deposition cycle, comprising:
flowing processing gas molecules mixture into a processing chamber having a substrate therein, wherein the processing gas mixture comprises precursor gas molecules selected from the group consisting of tetramethylcyclotetrasilazanes, hexamethylcyclotetrasilazanes (HMCTZ), octamethylcyclotetrasilazanes, hexamethyldisilazane (HMDS), bis-diethylamine silane (BDEAS), bis(tertiary-butylamino)silane (BTBAS), tris(dimethylamino)silane (TDMAS), or combinations thereof;
generating a plasma in the processing chamber at an RF power density from about 0.01 W/cm 2 to about 40 W/cm 2 and at a temperature between about 20° C. to about 480° C. to activate the precursor gas by preferentially breaking labile bonds in the precursor gas molecules to provide one or more reaction sites along a precursor gas molecule;
forming a precursor material layer on the substrate, wherein the activated precursor gas molecules bonds to a substrate surface at the reaction site; and
performing a plasma treatment process on the precursor material layer to form a conformal silicon nitride layer;
repeating the deposition cycle so that the conformal silicon nitride layer is from 90 Å to about 110 Å thick; and
performing a UV cure process on the conformal silicon nitride layer without exposing the silicon nitride layer to oxygen.
19. The method of claim 18 , wherein the plasma treatment process cross-links the precursor gas molecules in the precursor material layer and wherein the UV cure process tunes the amount of stress in the conformal silicon nitride layer.
20. The method of claim 18 , wherein the conformal silicon nitride layer is doped with carbon.