Surface modification layer for conductive feature formation
Embodiments described herein relate generally to methods for forming a conductive feature in a dielectric layer in semiconductor processing and structures formed thereby. In some embodiments, a structure includes a dielectric layer over a substrate, a surface modification layer, and a conductive feature. The dielectric layer has a sidewall. The surface modification layer is along the sidewall, and the surface modification layer includes phosphorous and carbon. The conductive feature is along the surface modification layer.
1. A structure comprising:
a dielectric layer over a substrate, the dielectric layer having a sidewall;
a surface modification layer along the sidewall, the surface modification layer comprising phosphorous and carbon; and
a conductive feature in physical contact with the surface modification layer, the conductive feature not comprising a barrier layer.
2. The structure of claim 1 , wherein the surface modification layer is a monolayer.
3. The structure of claim 1 , wherein a thickness of the surface modification layer is in a range from about 1 nm to about 2 nm.
4. The structure of claim 1 , wherein the dielectric layer is a SiOC material.
5. The structure of claim 1 , wherein the conductive feature is free from a metal-nitride.
6. A structure comprising:
a first dielectric layer over a substrate;
a first conductive feature disposed in the first dielectric layer;
a second dielectric layer over the first dielectric layer, the second dielectric layer having sidewalls;
a surface modification layer along the sidewalls of the second dielectric layer, the surface modification layer comprising phosphorous and carbon; and
a second conductive feature disposed between the sidewalls of the second dielectric layer, the second conductive feature contacting the first conductive feature, wherein the second conductive feature is free from a barrier layer.
7. The structure of claim 6 , wherein the surface modification layer is a monolayer.
8. The structure of claim 6 , wherein the second conductive feature is free from a metal-nitride.
9. The structure of claim 6 further comprising an etch stop layer over the first dielectric layer, the second dielectric layer being over the etch stop layer, the second conductive feature being disposed between and contacting sidewalls of the etch stop layer.
10. A method for semiconductor processing, the method comprising:
etching an opening through a dielectric layer, the dielectric layer being over a substrate;
exposing surfaces of the dielectric layer that define the opening to a phosphoric acid derivative, wherein the phosphoric acid derivative includes Di-(2-ethylhexyl)phosphoric acid, dihexylphosphoric acid, ethyl hexadecyl phosphate, n-Butyl-octyl-hydrogenphosphate, diisoamylphosphoric acid, ethyl octyl phosphate, or a combination thereof; and
depositing a conductive fill material in the opening.
11. The method of claim 10 , wherein exposing the surfaces of the dielectric layer to the phosphoric acid derivative comprises flowing a gas comprising the phosphoric acid derivative on the surfaces of the dielectric layer.
12. The method of claim 10 , wherein exposing the surfaces of the dielectric layer to the phosphoric acid derivative comprises exposing the surfaces of the dielectric layer to a wet solution comprising the phosphoric acid derivative and an organic solvent.
13. The method of claim 10 , wherein exposing the surfaces of the dielectric layer to the phosphoric acid derivative comprises forming a monolayer on the surfaces of the dielectric layer, forming the monolayer comprising reacting the phosphoric acid derivative with a material of the surfaces of the dielectric layer, the monolayer comprising phosphorous and carbon.
14. The method of claim 13 , wherein a thickness of the monolayer is in a range from about 1 nm to about 2 nm.
15. The method of claim 13 , wherein the conductive fill material abuts the monolayer.
16. The method of claim 10 , wherein etching the opening comprises using a plasma process.
17. The method of claim 10 , wherein after depositing the conductive fill material, no metal-nitride layer is disposed between the conductive fill material and the surfaces of the dielectric layer, the conductive fill material further being free from a metal-nitride.
18. The method of claim 10 , wherein:
the dielectric layer is over an etch stop layer;
etching the opening further comprises etching the opening through the etch stop layer to expose a conductive feature; and
exposing the surfaces of the dielectric layer to the phosphoric acid derivative further exposes surfaces of the etch stop layer and a surface of the conductive feature that further define the opening to the phosphoric acid derivative, the phosphoric acid derivative selectively reacting with the surfaces of the dielectric layer.
19. The method of claim 10 , wherein the dielectric layer is a SiOC material.
20. The structure of claim 6 , wherein the surface modification layer has a thickness of between about 1 nm and about 2 nm.