Method for integrating a ruthenium layer with bulk copper in copper metallization

1. A method for processing a substrate, comprising:

depositing a Ru metal layer onto the substrate in a chemical vapor deposition process;

thereafter, modifying the deposited Ru metal layer by nitridation to incorporate nitrogen species into the deposited Ru metal layer;

thereafter, treating the modified Ru metal layer by exposing the modified Ru metal layer to a hydrogen-containing plasma, or annealing the substrate, or a combination thereof;

thereafter, depositing an ultra thin Cu layer onto the modified and treated Ru metal layer; and

plating a bulk Cu layer onto the ultra thin Cu layer.

2. The method according to claim 1 , wherein the depositing a Ru metal layer comprises:

exposing the substrate to a process gas comprising a ruthenium carbonyl precursor and CO gas.

3. The method according to claim 1 , wherein the depositing a Ru metal layer comprises:

exposing the substrate to a process gas comprising Ru 3 (CO) 12 and CO gas.

4. The method according to claim 1 , wherein the depositing a Ru metal layer comprises:

exposing the substrate to a process gas comprising a ruthenium organometallic precursor and a reducing gas.

5. The method according to claim 4 , wherein the ruthenium organometallic precursor comprises (2,4-dimethylpentadienyl) (ethylcyclopentadienyl) ruthenium, bis(2,4-dimethylpentadienyl) ruthenium, (2,4-dimethylpentadienyl) (methylcyclopentadienyl) ruthenium, or bis(ethylcyclopentadienyl) ruthenium, or a combination of two or more thereof.

6. The method according to claim 4 , wherein the reducing gas comprises H 2 or O 2 .

7. The method according to claim 1 , wherein the depositing a Ru metal layer further comprises:

maintaining the substrate at a temperature between about 100° C. and about 400° C.

8. The method according to claim 1 , wherein the depositing a Ru metal layer is performed at a process pressure between about 0.1 mTorr and about 200 mTorr.

9. The method according to claim 1 , wherein a thickness of the Ru metal layer is between about 1 nm and about 30 nm.

10. The method according to claim 1 , wherein a thickness of the Ru metal layer is between about 1.5 nm and about 10 nm.

11. The method according to claim 1 , wherein the modifying by nitridation comprises exposing the Ru metal layer to a nitrogen-containing plasma.

12. The method according to claim 11 , wherein the nitrogen-containing plasma comprises N 2 gas or NH 3 gas, and a noble gas.

13. The method according to claim 1 , wherein the modifying is performed at a gas pressure between about 10 mTorr and about 1000 Torr.

14. The method according to claim 1 , wherein the modifying

is performed at a substrate temperature between about 100° C. and about 500° C.

15. The method according to claim 1 , wherein the hydrogen-containing plasma comprises H 2 gas and a noble gas.

16. The method according to claim 1 ,

wherein the treating is by annealing the substrate in the absence of a plasma at a substrate temperature between about 100° C. and about 500° C. while exposing the modified Ru metal layer to a noble gas, N 2 gas, NH 3 gas, H 2 gas, or a combination of two or more thereof.

17. The method according to claim 1 , wherein the ultra thin Cu layer is deposited by an ionized physical vapor deposition process.

18. The method according to claim 1 , wherein a thickness of the ultra thin Cu layer is between about 1 nm and about 30 nm.

19. The method according to claim 1 , wherein a thickness of the ultra thin Cu layer is between about 5 nm and about 20 nm.

20. A non-transitory computer readable medium containing program instructions for execution on a processor, which when executed by the processor, cause a processing tool to perform the steps in the method recited in claim 1 .

21. A method for processing a substrate, comprising:

depositing a Ru metal layer onto the substrate in a chemical vapor deposition process from a process gas comprising Ru 3 (CO) 12 and CO gas, the Ru metal layer having a thickness between about 1 nm and about 30 nm;

thereafter, modifying the deposited Ru metal layer by nitridation to incorporate nitrogen species into the deposited Ru metal layer;

thereafter, treating the modified Ru metal layer by exposing the modified Ru metal layer to a plasma comprising H 2 gas and a noble gas, or annealing the substrate in the absence of a plasma at a substrate temperature between about 100° C. and about 500° C. while exposing the modified Ru metal layer to a noble gas, N 2 gas, NH 3 gas, or H 2 gas, or a combination of two or more thereof;

thereafter, depositing an ultra thin Cu layer onto the modified and treated Ru metal layer, the ultra thin Cu layer having a thickness between about 1 nm and about 30 nm; and

plating a Cu layer onto the ultra thin Cu layer.