Copper interconnect structure with manganese oxide barrier layer
View Patent ↗Low capacitance and high reliability interconnect structures and methods of manufacture are disclosed. The method includes forming a copper based interconnect structure in an opening of a dielectric material. The method further includes forming a capping layer on the copper based interconnect structure. The method further includes oxidizing the capping layer and any residual material formed on a surface of the dielectric material. The method further includes forming a barrier layer on the capping layer by outdiffusing a material from the copper based interconnect structure to a surface of the capping layer. The method further includes removing the residual material, while the barrier layer on the surface of the capping layer protects the capping layer.
1. A method, comprising:
forming a copper based interconnect structure comprising:
forming a first barrier layer coating sidewalls and a bottom of an opening of a dielectric material;
forming an Mn-containing layer on the first barrier layer; and
forming a copper layer on the Mn-containing layer;
forming a capping layer on the copper based interconnect structure, wherein the forming the capping layer creates a residual material on a surface of the dielectric material;
forming a second barrier layer on the capping layer by outdiffusing Mn from the Mn-containing layer to a surface of the capping layer; and
removing the residual material, while the second barrier layer on the surface of the capping layer protects the capping layer.
2. The method of claim 1 , wherein the forming the second barrier layer comprises outdiffusing Mn to the surface of the capping layer during an anneal process.
3. The method of claim 1 , wherein the forming the second barrier layer comprises outdiffusing Mn from the Mn-containing layer through both the copper layer and the capping layer during an anneal process.
4. The method of claim 3 , wherein:
a bottom surface of the capping layer is on an upper surface of the copper layer; and
the second barrier layer is on an upper surface and side surfaces of the capping layer.
5. The method of claim 4 , wherein the capping layer is composed of cobalt (Co), and further comprising oxidizing the capping layer and the residual material, the oxidizing forming a first cobalt oxide (CoO) passivation layer on the capping layer and a second CoO passivation layer on the residual material.
6. The method of claim 1 , further comprising performing a chemical mechanical polish on a top surface of the copper based interconnect structure and a top surface of the dielectric material prior to the forming the capping layer on the copper based interconnect structure.
7. The method of claim 1 , wherein the capping layer extends entirely across a top surface of the copper based interconnect structure.
8. The method of claim 1 , wherein the capping layer comprises cobalt or CoWP.
9. The method of claim 1 , wherein the first barrier layer comprises one of TaN and cobalt.
10. A method, comprising:
forming a copper based interconnect structure in a dielectric material, wherein the copper based interconnect structure comprises a copper layer and an Mn-containing layer;
forming a capping layer on the copper layer, wherein the forming the capping layer creates a residual material on a surface of the dielectric material;
forming a barrier layer on the capping layer by outdiffusing Mn from the Mn-containing layer to a surface of the capping layer; and
removing the residual material, while the barrier layer on the surface of the capping layer protects the capping layer.
11. The method of claim 10 , wherein the forming the barrier layer comprises outdiffusing Mn to the surface of the capping layer during an anneal process.
12. The method of claim 10 , wherein the forming the barrier layer comprises outdiffusing Mn from the Mn-containing layer through both the copper layer and the capping layer during an anneal process.
13. The method of claim 12 , wherein:
a bottom surface of the capping layer is on an upper surface of the copper layer; and
the barrier layer is on an upper surface and side surfaces of the capping layer.
14. The method of claim 10 , further comprising performing a chemical mechanical polish on a top surface of the copper based interconnect structure and a top surface of the dielectric material prior to the forming the capping layer on the copper based interconnect structure.
15. The method of claim 10 , wherein the capping layer extends entirely across a top surface of the copper based interconnect structure.
16. The method of claim 10 , wherein the capping layer comprises cobalt or CoWP.
17. The method of claim 10 , wherein the barrier layer is formed on a top surface and side surfaces of the capping layer.
18. A method, comprising:
forming a capping layer on a copper layer, wherein the forming the capping layer creates a residual material on a surface of a dielectric material;
forming a barrier layer on the capping layer by outdiffusing Mn from an underlying Mn-containing layer, through both the copper layer and the capping layer, to at least one surface of the capping layer during an anneal process; and
removing the residual material, while the barrier layer on the surface of the capping layer protects the capping layer.
19. The method of claim 18 , further comprising performing a chemical mechanical polish on a top surface of the copper layer and a top surface of the dielectric material prior to the forming the capping layer on the copper layer.
20. The method of claim 18 , wherein the at least one surface of the capping layer comprises a top surface and side surfaces of the capping layer such that the barrier layer is formed on the top surface and the side surfaces of the capping layer.