Selective formation of metallic films on metallic surfaces
Metallic layers can be selectively deposited on surfaces of a substrate relative to a second surface of the substrate. In preferred embodiments, the metallic layers are selectively deposited on copper instead of insulating or dielectric materials. In preferred embodiments, a first precursor forms a layer or adsorbed species on the first surface and is subsequently reacted or converted to form a metallic layer. Preferably the deposition temperature is selected such that a selectivity of above about 90% is achieved.
1. A method for selectively depositing a film on a substrate comprising a first metal surface and a second surface comprising silicon oxide, the method comprising one or more deposition cycles comprising:
contacting the substrate with a first vapor-phase precursor comprising Si or B; and
contacting the substrate with a second vapor-phase precursor comprising W,
wherein the film is deposited on the first metal surface relative to the second surface with a selectivity of above about 50%.
2. The method of claim 1 , wherein the first vapor-phase precursor comprises silane.
3. The method of claim 1 , wherein the first vapor phase precursor comprises disilane.
4. The method of claim 1 , wherein the first vapor phase precursor comprises trisilane.
5. The method of claim 1 , wherein the first vapor phase precursor comprises diborane.
6. The method of claim 1 , wherein the second vapor-phase precursor is WF 6 .
7. The method of claim 1 , wherein the film consists essentially of elemental metal.
8. The method of claim 1 , wherein the first metal surface comprises copper.
9. The method of claim 1 , wherein the first metal surface comprises a noble metal.
10. The method of claim 1 , wherein the second surface comprises a low-k material.
11. The method of claim 1 , wherein the second surface comprises SiO 2 .
12. The method of claim 1 , wherein the selectivity is above about 80%.
13. The method of claim 12 , wherein the selectivity is above about 90%.
14. The method of claim 12 , wherein the selectivity is above about 95%.
15. The method of claim 1 , further comprising repeating the deposition cycle two or more times in succession.
16. The method of claim 1 , further comprising cleaning the substrate prior to the one or more deposition cycles.
17. The method of claim 1 , further comprising treating the second surface prior to the one or more deposition cycles.
18. The method of claim 17 , wherein treating comprises silylation.
19. The method of claim 1 , wherein the deposition cycles are carried out at a deposition temperature of less than about 200° C.
20. The method of claim 19 , wherein the deposition temperature is less than about 150° C.