Process and chemistry of plating of through silicon vias

1. A method for depositing a material on a substrate, comprising:

depositing a conformal oxide layer over at least one sidewall and a bottom surface of a feature formed in a silicon substrate, wherein the silicon substrate comprises:

a field region surrounding the feature; and

a backside, wherein the feature extends from the field region toward the backside;

selectively removing a portion of the conformal oxide layer from the bottom surface of the feature to expose a portion of the silicon substrate;

depositing a metal seed layer on the exposed portion of the silicon substrate at the bottom surface of the feature;

forming a conformal barrier layer on the conformal oxide layer after depositing the metal seed layer on the exposed portion of the silicon substrate; and

exposing the silicon substrate to an electroplating process by flowing a current through the backside of the silicon substrate to form a metal layer on the metal seed layer.

2. The method of claim 1 , wherein the exposing the silicon substrate to an electroplating process by flowing a current through the backside of the silicon substrate to form a metal layer on the metal seed layer comprises exposing the backside of the silicon substrate to a wet contact solution comprising a hydrofluoric acid solution and exposing the metal seed layer to a copper containing solution.

3. The method of claim 2 , wherein the wet contact solution further comprises potassium fluoride.

4. The method of claim 1 , wherein the conformal barrier layer comprises titanium nitride (TiN), tungsten nitride (WN), or tungsten-silicon nitride (WSiN).

5. The method of claim 4 , wherein the conformal oxide layer is a silicon dioxide layer.

6. The method of claim 1 , wherein the metal of the metal seed layer is selected from cobalt and nickel.

7. The method of claim 6 , wherein the metal of the metal seed layer is nickel deposited by an electroless process.

8. The method of claim 6 , wherein the metal of the metal seed layer is cobalt deposited by either an electroless process or a chemical vapor deposition process.

9. The method of claim 1 , wherein the metal layer comprises copper.

10. The method of claim 1 , wherein the feature is an aperture selected from contacts, vias, and lines.

11. The method of claim 1 , wherein the exposing the silicon substrate to an electroplating process by flowing a current through a backside of the silicon substrate to form a metal layer on the metal seed layer comprises exposing the backside of the silicon substrate to a potassium hydroxide solution and exposing the metal seed layer to a copper containing solution.

12. A method for depositing a material on a substrate, comprising:

depositing an oxide layer over at least one sidewall and a bottom surface of a feature formed in a silicon substrate, wherein the silicon substrate comprises:

a field region surrounding the feature and having an oxide layer disposed thereon; and

a backside, wherein the feature extends from the field region toward the backside;

selectively removing a portion of the oxide layer from the bottom surface of the feature to expose a portion of the silicon substrate, wherein at least a portion of the oxide layer remains on the at least one sidewall;

depositing a metal seed layer on the exposed portion of the silicon substrate at the bottom surface of the feature;

forming a barrier layer on the portion of the oxide layer remaining on the at least one sidewall, wherein the barrier layer comprises titanium nitride (TiN), tungsten nitride (WN), or tungsten-silicon nitride (WSiN); and

exposing the silicon substrate to an electroplating process, comprising:

exposing the backside of the silicon substrate to a potassium hydroxide solution and exposing the seed layer to a copper containing solution; and

flowing a current through the backside of the silicon substrate to form a metal layer on the metal seed layer.

13. The method of claim 12 , wherein the metal of the metal seed layer is nickel deposited by an electroless process.

14. The method of claim 13 , wherein the metal layer comprises copper.

15. The method of claim 12 , wherein the feature is an aperture selected from contacts, vias, and lines.

16. A method for depositing a material on a substrate, comprising:

depositing an oxide layer over at least one sidewall and a bottom surface of a feature formed in a silicon substrate, wherein the silicon substrate comprises:

a field region surrounding the feature and having an oxide layer disposed thereon; and

a backside, wherein the feature extends from the field region toward the backside;

selectively removing a portion of the oxide layer from the bottom surface of the feature to expose a portion of the silicon substrate, wherein selectively removing a portion of the oxide layer comprises exposing the oxide layer to an argon-based sputter etching process followed by a wet etch process, and at least a portion of the oxide layer remains on the at least one sidewall;

depositing a metal seed layer on the exposed portion of the silicon substrate at the bottom surface of the feature;

forming a barrier layer on the portion of the oxide layer remaining on the at least one sidewall; and

exposing the silicon substrate to an electroplating process by flowing a current through the backside of the silicon substrate to form a metal layer on the metal seed layer.

17. A method for depositing a material on a substrate, comprising:

depositing a conformal oxide layer over at least one sidewall and a bottom surface of a feature formed in a silicon substrate, wherein the silicon substrate comprises:

a field region surrounding the feature; and

a backside, wherein the feature extends from the field region toward the backside;

selectively removing a portion of the conformal oxide layer from the bottom surface of the feature to expose a portion of the silicon substrate;

depositing a metal seed layer on the exposed portion of the silicon substrate at the bottom surface of the feature; and

exposing the silicon substrate to an electroplating process, comprising:

exposing the backside of the silicon substrate to a wet contact solution comprising a hydrofluoric acid solution and potassium fluoride;

exposing the seed layer to a copper containing solution; and

flowing a current through the backside of the silicon substrate to form a metal layer on the metal seed layer.

18. The method of claim 17 , wherein the metal layer comprises copper and the metal of the metal seed layer is selected from cobalt and nickel.

19. A method for depositing a material on a substrate, comprising:

depositing a conformal oxide layer over at least one sidewall and a bottom surface of a feature formed in a silicon substrate, wherein the silicon substrate comprises:

a field region surrounding the feature; and

a backside, wherein the feature extends from the field region toward the backside;

selectively removing a portion of the conformal oxide layer from the bottom surface of the feature to expose a portion of the silicon substrate;

depositing a metal seed layer on the exposed portion of the silicon substrate at the bottom surface of the feature;

forming a conformal barrier layer on the oxide layer after depositing the metal seed layer on the exposed silicon substrate; and

exposing the silicon substrate to an electroplating process, comprising:

exposing the backside of the silicon substrate to a potassium hydroxide solution;

exposing the metal seed layer to a copper containing solution; and

flowing a current through the backside of the silicon substrate to form a metal layer on the metal seed layer.

20. The method of claim 19 , wherein the metal layer comprises copper and the metal of the metal seed layer is selected from cobalt and nickel.