Method of fabricating semiconductor device with adhesion layer

1. A method of fabricating a semiconductor structure, the method comprising:

depositing a dielectric layer over a gate stack;

removing a portion of the gate stack to form a trench in the dielectric layer;

depositing an insulating layer in the trench;

depositing an adhesion layer over the insulating layer; and

performing a hydrogen-containing plasma treatment on the adhesion layer.

2. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

performing the hydrogen-containing plasma treatment during the depositing the adhesion layer.

3. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

performing the hydrogen-containing plasma treatment after the depositing the adhesion layer.

4. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

flowing at least one of hydrogen, ammonia gas, or nitrogen-hydrogen gas over the adhesion layer.

5. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

mixing the at least one of hydrogen, ammonia gas, or nitrogen-hydrogen gas with an inert gas.

6. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

flowing a hydrogen-containing gas at a flow rate ranging from about 5 standard cubic centimeters per minute (sccm) to about 500 sccm over the adhesion layer.

7. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

performing the hydrogen-containing plasma treatment at a temperature ranging from about 15 degrees Celsius to about 420 degrees Celsius.

8. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

treating the adhesion layer at a pressure ranging from about 35 mTorr to about 10 Torr.

9. The method of claim 1 , wherein the performing the hydrogen-containing plasma treatment on the adhesion layer comprises:

treating the adhesion layer for a duration ranging from about 5 seconds to about 300 seconds.

10. The method of claim 1 , further comprising:

forming an interfacial layer in the trench;

depositing a work function layer in the trench and over the insulating layer;

depositing a blocking layer in the trench and over the adhesion layer; and

depositing a conductive material in the trench and over the blocking layer.

11. A method of manufacturing a semiconductor device, the method comprising:

forming a trench in an inter-layer dielectric (ILD) over a fin structure and an isolation feature;

depositing a first conductive layer in the trench;

performing a first redox reaction on the first conductive layer;

depositing a second conductive layer in the trench; and

performing a second redox reaction on the second conductive layer.

12. The method of claim 11 , wherein the performing the first redox reaction comprises:

exposing the first conductive layer to a hydrogen-containing gas or carbon monoxide.

13. The method of claim 11 , wherein the performing the first redox reaction comprises:

annealing the first conductive layer in a hydrogen-containing gas environment at a temperature ranging from about 650 degree Celsius to about 950 degree Celsius.

14. The method of claim 11 , wherein the performing the first redox reaction comprises:

removing oxygen atoms from a surface of the first conductive layer extending to a depth of about 100 angstrom (Å).

15. The method of claim 14 , wherein the removing oxygen atoms comprises:

reducing a concentration of oxygen atoms by at least 5% by weight.

16. The method of claim 11 , wherein the performing the first redox reaction comprises:

biasing a substrate with a direct current (DC) bias voltage ranging from about 50 watts to about 5000 watts, wherein the substrate is in contact with the fin structure.

17. The method of claim 11 , wherein the performing the second redox reaction comprises:

exposing the second conductive layer to a hydrogen-containing gas or a carbon monoxide.

18. The method of claim 11 , further comprising:

depositing a third conductive layer in the trench; and

performing a third redox reaction on the third conductive layer.

19. A method of fabricating a semiconductor structure, the method comprising:

depositing a dielectric layer over a transistor element;

forming a trench in the dielectric layer;

depositing an insulating layer in the trench;

depositing an adhesion layer over the insulating layer; and

performing a redox reaction in-situ with the depositing of the adhesion layer.

20. The method of claim 19 , wherein the performing of the redox reaction comprises performing at least one of a plasma treatment, and the redox reaction involves a hydrogen-containing gas or carbon monoxide.