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 dielectric surface, the method comprising one or more deposition cycles comprising:
contacting the substrate with a first vapor-phase precursor; and
contacting the substrate with a second vapor-phase precursor comprising a metal selected from W, Ta, Nb, Ti, Mo and V,
wherein the film is deposited on the first metal surface relative to the second dielectric surface with a selectivity of above about 50%.
2. The method of claim 1 , wherein the first metal surface comprises copper.
3. The method of claim 1 , wherein the film comprises a metal nitride.
4. The method of claim 1 , wherein the second precursor is a metal halide.
5. The method of claim 4 , wherein the second precursor comprises a metal fluoride.
6. The method of claim 1 , wherein the metal surface comprises a noble metal.
7. The method of claim 1 , wherein the film comprises a metal silicide.
8. The method of claim 1 , wherein the film consists essentially of elemental metal.
9. The method of claim 1 , wherein the second dielectric surface comprises SiO 2 .
10. The method of claim 1 , wherein the first precursor comprises Si or B.
11. The method of claim 1 , wherein the second dielectric surface comprises a low k material with a dielectric value of less than about 4.0.
12. The method of claim 1 , wherein the selectivity is above about 90%.
13. The method of claim 1 , further comprising repeating the deposition cycle two or more times.
14. The method of claim 1 , further comprising cleaning the substrate prior to the contacting step.
15. The method of claim 1 , wherein the temperature of the substrate is less than about 175° C.
16. A method for selectively depositing a film on a substrate comprising a first copper surface and a second dielectric surface, the method comprising one or more deposition cycles comprising:
contacting the substrate with a first precursor comprising Si or B; and
contacting the substrate with a second precursor comprising a metal halide, wherein metal halide comprises a metal selected from W, Ta, Nb, Ti, Mo and V; and
wherein the film is deposited on the first copper surface with a selectivity of greater than about 90% relative to the second dielectric surface.
17. The method of claim 16 , wherein the one or more deposition cycles are carried out at a temperature less than about 150° C.
18. The method of claim 16 , wherein the second precursor comprises a metal fluoride.
19. The method of claim 16 , wherein the first precursor comprises silane, disilane, trisilane or diborane.