Interconnect structure
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 of making an interconnect structure comprising:
forming a copper interconnect structure in a dielectric material;
forming a capping layer in contact with a top surface of the copper interconnect structure, wherein an interface of a bottom surface of the capping layer and the top surface of the copper interconnect structure is co-planar with a top surface of the dielectric material; and
forming a barrier layer outdiffused from a top surface and side surfaces of the capping layer,
wherein the copper interconnect structure comprises:
a layer of Tantalum Nitride (TaN);
a layer of CuMn directly on the TaN layer; and
an electroplated copper layer on the CuMn layer.
2. The method of claim 1 , wherein the capping layer comprises Ru and the barrier layer comprises MnO.
3. The method of claim 2 , further comprising forming a barrier layer at an interface of the copper interconnect structure and the dielectric material.
4. The method of claim 1 , wherein the capping layer comprises cobalt and the barrier layer comprises MnO.
5. The method of claim 4 , further comprising forming a barrier layer at an interface of the copper interconnect structure and the dielectric material.
6. The method of claim 5 , further comprising oxidizing the capping layer.
7. The method of claim 1 , wherein the capping layer extends entirely across a topmost surface of the copper interconnect structure.
8. The method of claim 1 , wherein the barrier layer comprises Mn outdiffused from the CuMn layer to an upper surface of the capping layer during an anneal process.
9. A method of making an interconnect structure comprising:
forming an interconnect structure in a dielectric material;
forming a capping layer in contact with a top surface of the interconnect structure, wherein an interface of a bottom surface of the capping layer and the top surface of the interconnect structure is co-planar with a top surface of the dielectric material; and
forming a barrier layer outdiffused from a top surface and side surfaces of the capping layer,
wherein the interconnect structure comprises:
a layer of Tantalum Nitride (TaN);
a layer of CuMn on the TaN layer; and
an electroplated copper layer on the CuMn layer.
10. The method of claim 9 , wherein the capping layer comprises Ru and the barrier layer comprises MnO.
11. The method of claim 10 , further comprising forming a barrier layer at an interface of the interconnect structure and the dielectric material.
12. The method of claim 9 , wherein the capping layer comprises cobalt and the barrier layer comprises MnO.
13. The method of claim 12 , further comprising forming a barrier layer at an interface of the interconnect structure and the dielectric material.
14. The method of claim 13 , further comprising oxidizing the capping layer.
15. The method of claim 9 , wherein the capping layer extends entirely across a topmost surface of the interconnect structure.
16. The method of claim 9 , wherein the barrier layer comprises Mn outdiffused from the CuMn layer to an upper surface of the capping layer during an anneal process.
17. A method of making an interconnect in a semiconductor structure, the method comprising:
forming a self-aligned barrier layer on a capping layer by outdiffusing atoms from an underlying layer, through both a first layer and the capping layer, to an outer surface of the capping layer.
18. The method of claim 17 , wherein the underlying layer comprises Mn and the atoms are Mn atoms.
19. The method of claim 17 , wherein the self-aligned barrier layer is provided over at least a top surface of the capping layer.
20. The method of claim 17 , wherein the capping layer comprises Ru and the barrier layer comprises MnO.