Selective formation of metallic films on metallic surfaces
Metallic layers can be selectively deposited on one surface of a substrate relative to a second surface of the substrate. In some embodiments, the metallic layers are selectively deposited on copper instead of insulating or dielectric materials. In some embodiments, a first precursor forms a layer on the first surface and is subsequently reacted or converted to form a metallic layer. The deposition temperature may be selected such that a selectivity of above about 50% or even 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:
cleaning the substrate;
forming a surface termination on the second dielectric surface;
after cleaning carrying out one or more deposition cycles at a temperature of less than 150° C., each cycle comprising:
contacting the substrate with a first precursor; and
contacting the substrate with a second precursor comprising a metal,
wherein deposition on the first metal surface relative to the second dielectric surface has a selectivity of greater than about 50%.
2. The method of claim 1 , wherein the one or more deposition cycles are carried out prior to forming the surface termination on the second dielectric surface.
3. The method of claim 1 , wherein the one or more deposition cycles are carried out after forming the surface termination on the second dielectric surface.
4. The method of claim 3 , wherein the cleaning is carried out after forming the surface termination on the second dielectric surface.
5. The method of claim 1 , wherein the surface termination is formed in a first reaction chamber and the one or more deposition cycles are carried out in a second, different reaction chamber.
6. The method of claim 1 , wherein the first precursor comprises Si or B.
7. The method of claim 1 , wherein the second precursor comprises a metal selected from W, Ta, Nb, Ti, Mo and V.
8. The method of claim 7 , wherein the second precursor comprises WF 6 .
9. The method of claim 1 , wherein cleaning comprises removing a passivation layer from the first metal surface.
10. The method of claim 1 , wherein cleaning comprises exposing the substrate to a plasma.
11. The method of claim 1 , wherein forming the surface termination comprises silylation of the second dielectric surface.
12. The method of claim 1 , wherein forming the surface termination comprises forming —Si(CH 3 ) 3 groups on the second dielectric surface.
13. The method of claim 1 , wherein the first metal surface comprises copper.
14. The method of claim 1 , wherein the film comprises a metal nitride or metal silicide.
15. The method of claim 1 , additionally comprising annealing the substrate after cleaning and prior to carrying out the one or more deposition cycles.
16. The method of claim 1 , wherein the method has a selectivity for depositing material on the first metal surface relative to the second dielectric surface of above about 90%.
17. A method for selectively depositing a film on a first metal surface of a substrate relative to a second dielectric surface of the substrate, the method comprising:
conducting a dielectric restoration step;
carrying out one or more deposition cycles at a temperature of less than 150° C., each cycle comprising alternately and sequentially contacting the substrate with a first precursor and a second precursor comprising a metal selected from W, Ta, Nb, Ti, Mo and V,
wherein deposition on the first metal surface relative to the second dielectric surface is greater than about 50% selective.
18. The method of claim 17 , wherein the dielectric restoration step and the deposition cycles are conducted in different reaction spaces.
19. The method of claim 17 , wherein the dielectric restoration step comprises contacting the second dielectric surface with SiHxLy, where L is selected from alkyl, alkenyl, alkynyl, alkoxide and amide groups.
20. The method of claim 17 , wherein the dielectric restoration step comprises silylation of the second dielectric surface.
21. The method of claim 17 , wherein the dielectric restoration step comprises forming —Si(CH 3 ) 3 groups on the second dielectric surface.
22. The method of claim 17 , wherein the dielectric restoration step is conducted prior to conducting the one or more deposition cycles.
23. The method of claim 17 , wherein the selectivity is greater than about 90%.
24. The method of claim 17 , additionally comprising annealing the substrate at a temperature from 150° C. to 400° C. prior to conducting the deposition cycles.
25. The method of claim 17 , wherein an organic layer is formed on the dielectric surface prior to carrying out the one or more deposition cycles.
26. The method of claim 25 , wherein the organic layer makes the dielectric layer more resistant to metal fluorides.
27. The method of claim 17 , wherein the film is a metal nitride or metal silicide.
28. A method for selectively depositing a film on a substrate comprising a first metal surface and a second dielectric surface, the method comprising:
cleaning the substrate;
forming a surface termination on the second dielectric surface;
after cleaning carrying out one or more deposition cycles at a temperature of less than 150° C., each cycle comprising:
exposing the substrate to a first precursor; and
exposing the substrate to a second precursor comprising a metal,
wherein a thin film is selectively deposited on the first metal surface relative to the second dielectric surface and the selectivity is greater than about 50%.
29. The method of claim 28 , wherein the one or more cycles are carried out prior to forming a surface termination on the second dielectric surface.
30. The method of claim 28 , wherein the second precursor comprises a metal selected from W, Ta, Nb, Ti, Mo and V.
31. The method of claim 28 , wherein forming a surface termination comprises forming —Si(CH 3 ) 3 groups on the second dielectric surface.