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 forming an integrated circuit comprising 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;
removing excess first vapor-phase precursor;
contacting the substrate with a second vapor-phase second reactant comprising a metal halide, wherein the metal halide comprises W or Mo, and
removing excess second vapor-phase reactant,
wherein the film is deposited with a selectivity for the first metal surface relative to the second dielectric surface of above 80%.
2. The method of claim 1 , wherein the second vapor-phase reactant is WF 6 .
3. The method of claim 1 , wherein the first vapor-phase precursor is a silane or borane.
4. The method of claim 1 , wherein the film comprises a metal nitride.
5. The method of claim 1 , wherein the film comprises a metal silicide.
6. The method of claim 1 , wherein the film consists essentially of elemental metal.
7. The method of claim 1 , wherein the first metal surface comprises copper.
8. The method of claim 1 , wherein the first metal surface comprises a noble metal.
9. The method of claim 1 , wherein the second surface comprises a low-k material.
10. The method of claim 9 , wherein the low-k material has a dielectric value of less than about 4.
11. The method of claim 1 , wherein the second surface comprises SiO 2 .
12. The method of claim 1 , wherein the selectivity is above 90%.
13. The method of claim 1 , wherein the deposition cycle is repeated two or more times in succession.
14. The method of claim 1 , wherein the one or more deposition cycles are carried out at a deposition temperature of less than about 200° C.
15. The method of claim 14 , wherein the deposition temperature is less than about 150° C.
16. The method of claim 1 , further comprising cleaning the substrate prior to the one or more deposition cycles.
17. The method of claim 16 , wherein cleaning comprises removing a passivation layer from the first metal surface.
18. The method of claim 16 , wherein cleaning comprises exposing the first metal surface to NH 3 plasma.
19. The method of claim 1 , further comprising treating the second surface prior to the one or more deposition cycles.
20. The method of claim 19 , wherein treating comprises silylation.