Formation of composite tungsten films
Embodiments of the invention provide methods for depositing tungsten materials. In one embodiment, a method for forming a composite tungsten film is provided which includes positioning a substrate within a process chamber, forming a tungsten nucleation layer on the substrate by subsequently exposing the substrate to a tungsten precursor and a reducing gas containing hydrogen during a cyclic deposition process, and forming a tungsten bulk layer during a plasma-enhanced chemical vapor deposition (PE-CVD) process. The PE-CVD process includes exposing the substrate to a deposition gas containing the tungsten precursor while depositing the tungsten bulk layer over the tungsten nucleation layer. In some example, the tungsten nucleation layer has a thickness of less than about 100 Å, such as about 15 Å. In other examples, a carrier gas containing hydrogen is constantly flowed into the process chamber during the cyclic deposition process.
1. A method for forming a composite tungsten film, comprising:
positioning a substrate within a process chamber;
forming a tungsten nucleation layer on the substrate by subsequently exposing the substrate to a tungsten precursor and a reducing gas during a cyclic deposition process, wherein the reducing gas comprises hydrogen gas; and
forming a tungsten bulk layer during a plasma-enhanced chemical vapor deposition process, comprising:
exposing the substrate to a deposition gas comprising the tungsten precursor; and
depositing the tungsten bulk layer over the tungsten nucleation layer.
2. The method of claim 1 , wherein a plasma is ignited by an electric field produced between a showerhead electrode and a support pedestal electrode during the plasma-enhanced chemical vapor deposition process.
3. The method of claim 1 , wherein a plasma is ignited by an electric field produced from a support pedestal coupled to a radio frequency source during the plasma-enhanced chemical vapor deposition process.
4. The method of claim 1 , wherein a plasma is ignited by an electric field produced from a showerhead coupled to a radio frequency source during the plasma-enhanced chemical vapor deposition process.
5. The method of claim 1 , wherein a plasma is ignited by a remote plasma source coupled to the process chamber during the plasma-enhanced chemical vapor deposition process.
6. The method of claim 1 , wherein the tungsten precursor comprises tungsten hexafluoride and the reducing gas further comprises diborane or silane.
7. The method of claim 1 , wherein a carrier gas comprising hydrogen is constantly flowed into the process chamber during the cyclic deposition process.
8. A method for forming a composite tungsten film, comprising:
positioning a substrate within a process chamber;
forming a tungsten nucleation layer on the substrate by subsequently exposing the substrate to a tungsten precursor and a reducing gas during a cyclic deposition process, wherein the tungsten nucleation layer has a thickness of less than about 100 Å; and
forming a tungsten bulk layer during a chemical vapor deposition process, comprising:
exposing the substrate to a deposition gas comprising the tungsten precursor; and
depositing the tungsten bulk layer over the tungsten nucleation layer.
9. The method of claim 8 , wherein the tungsten nucleation layer has a thickness of about 15 Å.
10. The method of claim 8 , wherein the tungsten bulk layer has a thickness within a range from about 300 Å to about 1,500 Å.
11. The method of claim 8 , wherein the reducing gas comprises hydrogen gas.
12. The method of claim 11 , wherein the reducing gas further comprises diborane or silane.
13. The method of claim 8 , wherein the chemical vapor deposition process is a thermally-enhanced chemical vapor deposition process or a plasma-enhanced chemical vapor deposition process.
14. The method of claim 13 , wherein a plasma is ignited within the process chamber during the plasma-enhanced chemical vapor deposition process, and the plasma is ignited by an electric field produced between a showerhead electrode and a support pedestal electrode.
15. The method of claim 14 , wherein a plasma is ignited within the process chamber during the plasma-enhanced chemical vapor deposition process, and the plasma is ignited by an electric field produced from a support pedestal coupled to a radio frequency source.
16. The method of claim 14 , wherein a plasma is ignited within the process chamber during the plasma-enhanced chemical vapor deposition process, and the plasma is ignited by an electric field produced from a showerhead coupled to a radio frequency source.
17. The method of claim 14 , wherein a plasma is ignited outside the process chamber by a remote plasma source coupled to the process chamber during the plasma-enhanced chemical vapor deposition process.
18. The method of claim 8 , wherein a carrier gas comprising hydrogen is constantly flowed into the process chamber during the cyclic deposition process.
19. A method for forming a composite tungsten film, comprising:
positioning a substrate within a process chamber;
forming a tungsten nucleation layer on the substrate by subsequently exposing the substrate to tungsten hexafluoride and a reducing gas during a cyclic deposition process, wherein the reducing gas comprises diborane and hydrogen gas; and
forming a tungsten bulk layer during a chemical vapor deposition process, comprising:
exposing the substrate to a deposition gas comprising the tungsten hexafluoride; and
depositing the tungsten bulk layer over the tungsten nucleation layer.
20. The method of claim 19 , wherein the chemical vapor deposition process is a thermally-enhanced chemical vapor deposition process or a plasma-enhanced chemical vapor deposition process.
21. The method of claim 20 , wherein a plasma is ignited within the process chamber during the plasma-enhanced chemical vapor deposition process, and the plasma is ignited by an electric field produced between a showerhead electrode and a support pedestal electrode.
22. The method of claim 20 , wherein a plasma is ignited within the process chamber during the plasma-enhanced chemical vapor deposition process, and the plasma is ignited by an electric field produced from a support pedestal coupled to a radio frequency source.
23. The method of claim 20 , wherein a plasma is ignited within the process chamber during the plasma-enhanced chemical vapor deposition process, and the plasma is ignited by an electric field produced from a showerhead coupled to a radio frequency source.
24. The method of claim 20 , wherein a plasma is ignited outside the process chamber by a remote plasma source coupled to the process chamber during the plasma-enhanced chemical vapor deposition process.
25. The method of claim 19 , wherein a carrier gas comprising hydrogen is constantly flowed into the process chamber during the cyclic deposition process.