Semiconductor device containing a ruthenium diffusion barrier and method of forming

• US 20070069383A1
• Filed: 09/28/2005
• Published: 03/29/2007
• Est. Priority Date: 09/28/2005
• Status: Abandoned Application

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Suzuki, Kenji
• Application Number:
  US11/238,500
• Publication Number:
  US 20070069383A1
• Time in Patent Office: Days
• US Class Current: 257/751
• CPC Class Codes: C23C 16/16 from metal carbonyl compounds
• CPC Class Codes: C23C 16/18 from metallo-organic compounds
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation
• CPC Class Codes: H01L 21/76864 Thermal treatment
• CPC Class Codes: H01L 21/76873 for electroplating

Abstract

A semiconductor device containing a ruthenium diffusion barrier and a method of forming and integrating the ruthenium diffusion barrier with bulk Cu. The method includes forming the Ru diffusion barrier by depositing a first Ru layer onto a substrate in a first CVD process, modifying the first Ru layer by oxidation, or nitridation, or a combination thereof, depositing a second Ru layer on the modified first Ru layer, and plating a Cu layer onto the Ru diffusion barrier. According to one embodiment of the invention, the Ru diffusion barrier is treated and/or an ultra thin Cu layer deposited on the Ru diffusion barrier prior to Cu plating.

Claims

1. A method for processing a substrate, comprising:

forming a Ru diffusion barrier on the substrate, the forming comprising;

depositing a first Ru layer;

modifying the first Ru layer by oxidation, or nitridation, or a combination thereof;

depositing a second Ru layer on the modified first Ru layer; and

plating a bulk Cu layer on the Ru diffusion barrier.

2. The method according to claim 1, wherein the depositing the first and second Ru layers 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 the first and second Ru layers comprises:

exposing the substrate to a process gas comprising Ru₃(CO)₁₂ and CO gas.

4. The method according to claim 1, wherein the depositing the first and second Ru layers 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 H₂ or O₂.

7. The method according to claim 1, wherein the depositing the first and second Ru layers 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 the first and second Ru layers 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 each of the first and second Ru layers is between about 1 nm and about 30 nm.

10. The method according to claim 1, wherein a thickness of each of the first and second Ru layers is between about 1.5 nm and about 10 nm.

11. The method according to claim 1, wherein the modifying by oxidation comprises exposing the first Ru layer to air, O₂ gas, or an oxygen-containing plasma.

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

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 further comprises:

annealing the substrate at a substrate temperature between about 100°

C. and about 500°

C.

15. The method according to claim 1, further comprising:

treating the Ru diffusion barrier prior to the plating, wherein the treating comprises exposing the Ru diffusion barrier to a hydrogen-containing plasma or annealing the substrate, or a combination thereof.

16. The method according to claim 15, wherein the annealing comprises:

maintaining the substrate at a temperature between about 100°

C. and about 500°

C.

17. The method according to claim 1, further comprising:

depositing an ultra thin Cu layer on the Ru diffusion barrier prior to the plating.

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

19. The method according to claim 17, wherein a thickness of the ultra thin Cu layer is between about 1 nm and about 30 nm.

20. The method according to claim 17, wherein a thickness of the ultra thin Cu layer is between about 5 nm and about 20 nm.

21. A 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.

22. A semiconductor device, comprising:

a substrate;

a Ru diffusion barrier comprising a modified first Ru layer formed on the substrate, wherein the first Ru layer is oxidized, nitridized, or a combination thereof, and a second Ru layer formed on the modified first Ru layer; and

a bulk Cu layer on the Ru diffusion barrier.

23. The semiconductor device according to claim 22, further comprising:

an ultra thin Cu layer between the Ru diffusion barrier and the bulk Cu layer.

24. The semiconductor device according to claim 22, further comprising:

a glue layer between the substrate and the Ru diffusion barrier, wherein the glue layer comprises a tantalum-containing layer, a tungsten-containing layer, or a manganese-containing layer.

25. The semiconductor device according to claim 22, wherein the substrate comprises a dielectric layer on which at least a portion of the Ru diffusion barrier is formed.

26. A method for processing a substrate, comprising:

forming a Ru diffusion barrier on the substrate, the forming comprising;

depositing a first Ru layer,

modifying the first Ru layer by oxidation, or nitridation, or a combination thereof, and

depositing a second Ru layer on the modified first Ru layer;

treating the Ru diffusion barrier, wherein the treating comprises exposing the Ru diffusion barrier to a hydrogen-containing plasma, or annealing the substrate, or a combination thereof;

depositing an ultra thin Cu layer on the treated Ru diffusion barrier; and

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