Methods for forming cobalt and ruthenium capping layers for interconnect structures
Methods and apparatus for forming an interconnect structure, the method including selectively depositing two or more capping layers atop a top surface of a via within a low-k dielectric layer, wherein the two or more capping layers include a first layer of ruthenium and a second layer of cobalt.
1. A method of forming an interconnect structure, the method comprising:
selectively depositing two or more capping layers atop a top surface of a via within a low-k dielectric layer, wherein the two or more capping layers comprise a first layer of ruthenium and a second layer of cobalt.
2. The method of claim 1 , wherein the via comprises a copper metal fill material.
3. The method of claim 1 , wherein the via comprises a copper metal fill material deposited atop a liner layer.
4. The method of claim 1 , wherein the via comprises a copper metal fill material deposited atop a liner layer, wherein the liner layer comprises ruthenium, cobalt, and combinations thereof.
5. The method of claim 1 , wherein the via comprises a copper metal fill material deposited atop a liner layer, and wherein the liner layer is deposited atop a barrier layer.
6. The method of claim 1 , wherein the two or more capping layers each have a thickness of 5 to 20 angstroms.
7. The method of claim 1 , wherein the first layer of ruthenium is directly atop the top surface of the via, and the second layer of cobalt is directly atop a top surface of the first layer of ruthenium.
8. The method of claim 1 , wherein the second layer of cobalt is directly atop the top surface of the via, and the first layer of ruthenium is directly atop a top layer of the second layer of cobalt.
9. A method of selectively depositing a capping layer atop a substrate having a metal surface and a low-k dielectric surface, comprising:
contacting the metal surface with one of ruthenium, cobalt, or combinations thereof to selectively deposit and form a first capping portion atop the metal surface, wherein a top surface of the metal surface is adjacent to a top surface of the low-k dielectric surface; and
contacting a top surface of the first capping portion with one of ruthenium, cobalt, or combinations thereof to selectively deposit and form a second capping portion atop the first capping portion, wherein the first capping portion and second capping portion comprise different material.
10. The method of claim 9 , wherein the low-k dielectric surface inhibits a deposition of ruthenium, cobalt, or combinations thereof thereon.
11. The method of claim 9 , wherein the metal surface is the top surface of a copper filled via.
12. The method of claim 11 , wherein the copper filled via comprises a liner layer, wherein the liner layer comprises ruthenium, cobalt, and combinations thereof.
13. The method of claim 9 , wherein the first capping portion and second capping portion each have a thickness of 5 to 20 angstroms.
14. The method of claim 9 , wherein the first capping portion comprises ruthenium and the second capping portion comprises cobalt.
15. The method of claim 9 , wherein the first capping portion comprises cobalt and the second capping portion comprises ruthenium.
16. The method of claim 9 , wherein the metal surface is a top surface of a copper filled via, wherein the via comprises a high aspect ratio and a hole of less than 20 nanometers.