Electroplated CoWP composite structures as copper barrier layers
View Patent ↗A composite material comprising a layer containing copper, and an electrodeposited CoWP film on the copper layer. The CoWP film contains from 11 atom percent to 25 atom percent phosphorus and has a thickness from 5 nm to 200 nm. The invention is also directed to a method of making an interconnect structure comprising: providing a trench or via within a dielectric material, and a conducting metal containing copper within the trench or the via; and forming a CoWP film by electrodeposition on the copper layer. The CoWP film contains from 10 atom percent to 25 atom percent phosphorus and has a thickness from 5 nm to 200 nm. The invention is also directed to a interconnect structure comprising a dielectric layer in contact with a metal layer; an electrodeposited CoWP film on the metal layer, and a copper layer on the CoWP film.
1. A method of making an interconnect structure comprising:
providing a trench or via within a dielectric material, and a conducting metal containing copper within the trench or the via; and
forming a CoWP film by electrodeposition on the copper layer, wherein the CoWP film contains 10 atom percent to 25 atom percent phosphorus.
2. The method of claim 1 wherein the CoWP film contains from 3 atom percent to 10 atom percent tungsten as measured by Rutherford backscattering spectroscopy.
3. The method of claim 1 wherein the CoWP film consists essentially of Co x W y P z ,wherein 0.68<x<0.88; 0.01<y<0.10; and z= (1−(x+y)) as measuredby Rutherford backscattering spectroscopy.
4. The method of claim 3 wherein 0.77<x<0.83 and 0.03<y<0.07.
5. The method of claim 1 further comprising depositing a metal layer along the sidewalls of the trench or via, wherein the copper layer is disposed between the CoWP film and the metal layer.
6. The method of claim 1 further comprising removing a portion of the copper conducting metal to form a recessed structure prior to forming the CoWP film.
7. The method of claim 6 further comprising forming a metal cap layer on the CoWP film.
8. The method of claim 1 wherein the CoWP film has a thickness from 5 nm to 50 nm.
9. The method of claim 1 wherein forming the CoWP film comprises providing an electroplating bath solution at a pH from 7 to 10.
10. The method of claim 9 wherein forming the CoWP film comprises applying a current density of 3 mA/cm 2 to 20 mA/cm 2 .
11. The method of claim 9 wherein Conning the CoWP films comprises applying a current density of 6 mA/cm 2 to 12 mA/cm 2 .
12. The method of claim 1 wherein the atom percent phosphorous is measured by Rutherford backscattering spectroscopy.
13. The method of claim 1 wherein forming the CoWP films comprises providing an electroplating bath solution at a pH from 8 to 9.
14. The method of claim 1 further comprising annealing the electrodeposited CoWP film in the presence of forming gas.
15. The method of claim 1 , wherein the CoWP film contains from 13.2 atom percent phosphorus to 25 atom percent phosphorus.
16. The method of claim 1 , wherein the CoWP film contains from 16.5 atom percent phosphorus to 25 atom percent phosphorus.
17. A method of making an interconnect structure comprising;
providing a tench or via in a dielectric layer, wherein the trench or the via has sidewall surfaces in contact with a metal layer;
forming a CoWP film by electrodeposition on the metal layer, wherein the CoWP film contains 10 atom percent to 25 atom percent phosphorus; and
forming a copper layer on the CoWP film.
18. The method of claim 17 wherein forming the CoWP films comprises providing an electroplating bath solution at a pH from 7 to 10.
19. The method of claim 18 wherein forming the CoWP films comprises applying a current density of 3 mA/cm 2 to 20 mA/cm 2 .
20. The method of claim 18 wherein forming the CoWP films comprises applying a current density of 6 mA/cm 2 to 12 mA/cm 2 .
21. The method of claim 17 wherein forming the CoWP films comprises maintaining the electroplating both solution at a pH from 8 to 9.
22. The method of claim 17 further comprising removing a portion of the copper conducting metal to form a recessed structure and forming a CoWP cap on the recessed copper conducting metal.
23. The method of claim 17 wherein the CoWP film has a thickness from 5 nm to 30 nm.
24. The method of claim 17 , wherein the CoWP film contains from 13.2 atom percent phosphorus to 25 atom percent phosphorus.
25. The method of claim 17 , wherein the CoWP film contains from 16.5 atom percent phosphorus to 25 atom percent phosphorus.