Selective tungsten deposition within trench structures
Embodiments of the disclosure provide methods which reduce or eliminate lateral growth of a selective tungsten layer. Further embodiments provide an integrated clean and deposition method which improves the selectivity of selectively deposited tungsten on trench structures. Additional embodiments provide methods for forming a more uniform and selective bottom-up gap fill for trench structures with improved film properties.
1. A deposition method comprising:
recessing a line of a metal material to form a trench having a bottom surface and two sidewalls, the trench having a depth to the bottom surface consisting essentially of the metal material and a width between the two sidewalls comprising a dielectric; and
selectively depositing a tungsten film on the recessed metal material and laterally bounded by the two sidewalls.
2. The method of claim 1 , wherein the metal material comprises one or more of copper, cobalt, tungsten or ruthenium.
3. The method of claim 1 , wherein the dielectric comprises silicon oxide, silicon nitride or combinations thereof.
4. The method of claim 1 , wherein the line of the metal material is recessed by a wet etch process.
5. The method of claim 1 , wherein the line of the metal material is recessed by a dry etch process.
6. The method of claim 1 , wherein the trench has a depth in a range of 3 nm to 200 nm.
7. The method of claim 6 , wherein the trench has an aspect ratio in a range of 1:1 to 20:1.
8. The method of claim 1 , wherein selectively depositing the tungsten film comprises exposing the trench to WF 6 and H 2 .
9. A selective deposition method comprising:
exposing a trench having a bottom surface consisting essentially of a metal material and two sidewalls comprising a dielectric to a plurality of chemical exposures to clean the surfaces of the metal material and the dielectric; and
selectively depositing a tungsten film on the cleaned surface of the metal material.
10. The method of claim 9 , wherein the plurality of chemical exposures comprises a plasma exposure.
11. The method of claim 10 , wherein the plurality of chemical exposures consists of a H 2 plasma exposure and an O 2 plasma exposure.
12. The method of claim 9 , wherein the plurality of chemical exposures comprises a thermal soak.
13. The method of claim 9 , wherein the plurality of chemical exposures comprises exposure to Ar, H 2 , O 2 or WF 6 .
14. The method of claim 9 , wherein the plurality of chemical exposures are performed at a temperature in a range of 20° C. to 400° C.
15. The method of claim 9 , wherein the tungsten film is deposited with a selectivity at least 1000 times greater than a similar process performed without the plurality of chemical exposures.
16. The method of claim 9 , wherein the tungsten film has a roughness of less than or equal to 1 nm.
17. The method of claim 8 , wherein the tungsten film has a grain size of less than or equal to 10 nm.
18. A deposition method comprising:
recessing a line of a metal material to form a trench having a bottom surface and two sidewalls, the trench having a depth to the bottom surface consisting essentially of the metal material and a width between the two sidewalls comprising a dielectric;
exposing the trench to a plurality of chemical exposures to clean the surfaces of the metal material and the dielectric; and
selectively depositing a tungsten film on the cleaned surface of the metal material.
19. The method of claim 18 , wherein the tungsten film is deposited entirely within the trench.
20. The method of claim 18 , wherein the tungsten film fills the trench.