High temperature tungsten metallization process
Embodiments of the invention provide an improved process for depositing tungsten-containing materials. In one embodiment, the method for forming a tungsten-containing material on a substrate includes forming an adhesion layer containing titanium nitride on a dielectric layer disposed on a substrate, forming a tungsten nitride intermediate layer on the adhesion layer, wherein the tungsten nitride intermediate layer contains tungsten nitride and carbon. The method further includes forming a tungsten barrier layer (e.g., tungsten or tungsten-carbon material) from the tungsten nitride intermediate layer by thermal decomposition during a thermal annealing process (e.g., temperature from about 700° C. to less than 1,000° C.). Subsequently, the method includes optionally forming a nucleation layer on the tungsten barrier layer, optionally exposing the tungsten barrier layer and/or the nucleation layer to a reducing agent during soak processes, and forming a tungsten bulk layer on or over the tungsten barrier layer and/or the nucleation layer.
1. A method for forming a tungsten-containing material on a substrate, comprising:
forming an adhesion layer comprising titanium nitride on a dielectric layer disposed on a substrate;
forming a tungsten nitride intermediate layer on the adhesion layer, wherein the tungsten nitride intermediate layer comprises tungsten nitride and carbon;
forming a tungsten barrier layer from the tungsten nitride intermediate layer during a thermal annealing process, wherein the tungsten barrier layer comprises metallic tungsten or tungsten-carbon material formed by thermal decomposition of the tungsten nitride intermediate layer;
forming a nucleation layer on the tungsten barrier layer; and
forming a tungsten bulk layer on the nucleation layer.
2. A method for forming a tungsten-containing material on a substrate, comprising:
forming an adhesion layer comprising titanium nitride on a dielectric layer disposed on a substrate;
forming a tungsten nitride intermediate layer on the adhesion layer, wherein the tungsten nitride intermediate layer comprises tungsten nitride and carbon;
heating the tungsten nitride intermediate layer to a decomposition temperature during a thermal annealing process, wherein the tungsten nitride intermediate layer decomposes to form a tungsten barrier layer comprising metallic tungsten or tungsten-carbon material and the decomposition temperature is within a range from about 700° C. to less than 1,000° C.;
forming a nucleation layer on the tungsten barrier layer; and
forming a tungsten bulk layer on the nucleation layer.
3. A method for forming a tungsten-containing material on a substrate, comprising:
forming an adhesion layer comprising titanium nitride on a dielectric layer disposed on a substrate;
forming a tungsten nitride intermediate layer on the adhesion layer, wherein the tungsten nitride intermediate layer comprises tungsten nitride and carbon;
forming a tungsten barrier layer from the tungsten nitride intermediate layer during a thermal annealing process, wherein the tungsten barrier layer comprises metallic tungsten or tungsten-carbon material formed by thermal decomposition of the tungsten nitride intermediate layer; and
forming a tungsten bulk layer directly on the tungsten barrier layer.
4. The method of claim 2 , wherein the adhesion layer has a thickness within a range from about 5 Å to about 25 Å.
5. The method of claim 2 , wherein the adhesion layer is deposited by atomic layer deposition or physical vapor deposition.
6. The method of claim 2 , wherein the tungsten nitride intermediate layer has a thickness within a range from about 5 Å to about 150 Å.
7. The method of claim 2 , wherein the tungsten nitride intermediate layer is deposited by atomic layer deposition, chemical vapor deposition, or physical vapor deposition.
8. The method of claim 2 , wherein the tungsten nitride intermediate layer has a tungsten concentration within a range from about 40 at % to about 60 at %, a nitrogen concentration within a range from about 20 at % to about 40 at %, and a carbon concentration within a range from about 5 at % to about 15 at %.
9. The method of claim 8 , wherein the tungsten barrier layer has a tungsten concentration within a range from about 70 at % to about 99 at %, a nitrogen concentration within a range from about 1 ppb to about 10 at %, and a carbon concentration within a range from about 1 ppb to about 10 at %.
10. The method of claim 9 , wherein the tungsten barrier layer has an electrical resistivity of less than 200 Ωμ-cm.
11. The method of claim 2 , wherein the tungsten nitride intermediate layer has a tungsten concentration within a range from about 40 at % to about 60 at %, a nitrogen concentration within a range from about 5 at % to about 20 at %, and a carbon concentration within a range from about 20 at % to about 40 at %.
12. The method of claim 11 , wherein the tungsten barrier layer has a tungsten concentration within a range from about 70 at % to about 99 at %, a nitrogen concentration within a range from about 1 ppb to about 10 at %, and a carbon concentration within a range from about 1 at % to about 15 at %.
13. The method of claim 12 , wherein the tungsten barrier layer has an electrical resistivity of less than 200 Ωμ-cm.
14. The method of claim 11 , wherein the tungsten nitride intermediate layer further comprises oxygen and has an oxygen concentration within a range from about 1 at % to about 10 at %.
15. The method of claim 14 , wherein the tungsten barrier layer further comprises oxygen and has an oxygen concentration within a range from about 1 ppb to about 1 at %.
16. The method of claim 2 , wherein the tungsten nitride intermediate layer is heated to a temperature within a range from about 875° C. to about 915° C. for a time period within a range from about 30 seconds to about 10 minutes during the thermal annealing process.
17. The method of claim 16 , wherein the time period is within a range from about 1 minute to about 5 minutes during the thermal annealing process.
18. The method of claim 2 , wherein the tungsten nitride intermediate layer is heated to a temperature within a range from about 750° C. to about 850° C. for a time period within a range from about 10 minutes to about 60 minutes during the thermal annealing process.
19. The method of claim 2 , wherein the tungsten nitride intermediate layer is formed by chemical vapor deposition, pulsed chemical vapor deposition, plasma-enhanced chemical vapor deposition, or plasma-enhanced, pulsed chemical vapor deposition.