Interconnect structure having a via with a via gouging feature and dielectric liner sidewalls for BEOL integration

1. A method of forming an interconnect structure comprising:

providing an initial interconnect structure that includes a lower interconnect level comprising a first dielectric layer having a first conductive material embedded therein, an upper interconnect level comprising a second dielectric layer having at least one via opening that exposes a portion of said first conductive material located atop said lower interconnect level, said lower and upper interconnect levels are separated in part by a dielectric capping layer, and a patterned hard mask on a surface of the said upper interconnect level;

removing an exposed portion of said conductive material to form at least one via gouging feature within said conductive material at a bottom of said at least one via opening;

forming a dielectric liner layer on all exposed surfaces;

forming at least one line opening in said second dielectric layer that extends above said at least one via opening;

selectively removing said dielectric liner layer from said at least one via gouging feature while keeping at least a portion of said dielectric liner layer at sidewalls of said at least one via opening unremoved;

forming a first diffusion barrier layer on all exposed surfaces; and

filling said at least one line opening and at least one via opening with a second conductive material.

2. The method of claim 1 , wherein said providing said initial interconnect structure comprises:

forming said first conductive material within said first dielectric layer;

forming a dielectric capping layer on said first dielectric layer and said first conductive material;

forming said second dielectric layer on said dielectric capping layer;

forming a patterned hard mask having via patterns on said second dielectric layer; and

transferring said via patterns into said second dielectric material layer said dielectric capping layer.

3. The method of claim 2 , further comprising, before said forming said first conductive material, forming a second diffusion barrier within said first dielectric layer.

4. The method of claim 1 , wherein said forming said at least one via gouging feature comprises ion-sputtering with a gas source.

5. The method of claim 4 , wherein said gas source comprises Ar, He, Xe, Ne, Kr, Rn, N 2 or H 2 .

6. The method of claim 1 , wherein said dielectric liner layer comprises a dielectric material.

7. The method of claim 6 , wherein said dielectric liner layer comprises SiO 2 , Si 3 N 4 , SiC, or a nitrogen and hydrogen doped silicon carbide (SiC(N, H)).

8. The method of claim 1 , wherein said forming said dielectric liner layer comprises a chemical vapor deposition (CVD), a plasma enhanced chemical vapor deposition (PECVD), an atomic layer deposition (ALD) process, or a plasma enhanced atomic layer deposition (PEALD).

9. The method of claim 1 , wherein said dielectric liner layer has a thickness in the range from about 2 nm to about 100 nm.

10. The method of claim 9 , wherein said dielectric liner layer has a thickness in the range from about 5 nm to about 20 nm.

11. The method of claim 1 , wherein said selectively removing said dielectric liner layer comprises a plasma stripping process, a wet chemical etching process, or an ion-sputtering process with a gas resource.

12. The method of claim 11 , wherein said plasma stripping process comprises a hydrogen plasma stripping process.

13. The method of claim 11 , wherein said wet chemical etching process comprises a wet chemical etching process with a dilute HF solution, a dilute HCl solution, a H 2 O 2 solution, or a combination comprising two or more of the foregoing solutions.

14. The method of claim 11 , wherein said gas source comprises Ar, He, Xe, Ne, Kr, Rn, N 2 or H 2 .