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, each cycle comprising:
contacting the substrate with a first precursor comprising silicon or boron to selectively form a layer of first material comprising Si or B on the first metal surface relative to the second dielectric surface; and
converting the first material on the first metal surface to a second metallic material by exposing the first material to a second precursor comprising metal, wherein the method has a selectivity for depositing material on the first metal surface relative to the second dielectric surface 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 second metallic material comprises a metal nitride.
4. The method of claim 1 , wherein the second metallic material comprises a transition metal.
5. The method of claim 4 , wherein the second metallic material comprises tungsten.
6. The method of claim 1 , wherein the metal surface comprises a noble metal.
7. The method of claim 1 , wherein the metallic material comprises a metal silicide.
8. The method of claim 1 , wherein the metallic material 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 second dielectric surface comprises a low k material with a dielectric value of less than about 4.0.
11. The method of claim 1 , wherein the first precursor comprises silane, disilane, or trisilane.
12. The method of claim 11 , wherein the second precursor comprises WF 6 , TaF 5 , NbF 5 , TiF 4 , MoF x , or VF x .
13. The method of claim 1 , wherein the first precursor is diborane.
14. The method of claim 1 , wherein the material of the first surface is not converted or reacted to form another compound during the selective deposition.
15. The method of claim 1 , wherein the second precursor comprises a metal halide.
16. The method of claim 1 , wherein the process has a selectivity for depositing material on the first surface versus the second surface of about above 90%.
17. The method of claim 1 , further comprising repeating the contacting and converting steps.
18. The method of claim 1 , further comprising cleaning the substrate prior to the contacting introducing step.
19. The method of claim 1 , wherein the first material has a thickness less than about 20 Å.
20. The method of claim 1 , wherein the temperature of the substrate is less than about 175° C.
21. The method of claim 1 , wherein the temperature of the substrate is selected such that the first material forms on the first metal surface with a selectivity of greater than about 90% versus the second dielectric surface.
22. The method of claim 1 , wherein converting the first material to second material is a replacement reaction.
23. The method of claim 1 , further comprising after the one or more deposition cycles:
contacting the substrate with a precursor comprising silicon or boron to form a layer comprising Si or B on the second metallic material.
24. The method of claim 23 , further comprising oxidizing the layer comprising Si or B to form SiO 2 or B 2 O 3 .
25. The method of claim 24 , further comprising removing the SiO 2 or B 2 O 3 by exposing the SiO 2 or B 2 O 3 to a metal halide source chemical.
26. The method of claim 1 , wherein the one or more deposition cycles are carried out at a temperature less than about 150° C.
27. 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:
contacting the substrate with a first precursor comprising silicon to selectively form a layer of first material comprising Si or B over the first copper surface relative to the second dielectric surface; and
converting the first material to a second metallic material by subsequently exposing the first material to a second precursor comprising a metal fluoride; wherein a temperature of the substrate is selected such that the first material forms on the first copper surface with a selectivity of greater than about 90% versus the second dielectric surface.
28. The method of claim 27 , wherein the temperature of the substrate is less than about 150° C.