Electroless deposition of continuous cobalt layer using complexed Ti3+ metal ions as reducing agents

Patent metadata

Field	Value
Publication number	US-9428836-B2
Application number	US-201414264994-A
Country	US
Kind code	B2
Filing date	Apr 29, 2014
Priority date	Apr 29, 2014
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

A solution for electroless deposition of cobalt is provided. A reducing agent of Ti 3+ ions is provided to the solution. Co 2+ ions are provided to the solution.

First claim

What is claimed is:

1. A solution for electroless deposition of cobalt, comprising:
a complexed reducing agent of Ti 3+ ions; and
Co 2+ ions, wherein the solution further comprises amine ligands.

2. The solution, as recited in claim 1 , further comprising at least one of gluconate or tartrate ions or methoxyacetate ions.

3. The solution, as recited in claim 2 , wherein the solution has a pH between 6 and 10, inclusive.

4. The solution, as recited in claim 1 , wherein a continuous cobalt layer of at least 99.9% purity is deposited.

5. The solution, as recited in claim 1 , wherein a ratio of Ti 3+ to Co 2+ ion is between 1:5 and 5:1.

6. The method, as recited in claim 1 , wherein the solution is boron, phosphorus, hydrazine, and formaldehyde free.

7. A method for providing an electroless plating of a cobalt containing layer, comprising:
providing a Ti 3+ concentrated stock solution;
providing a Co 2+ concentrated stock solution;
combining a flow from the Ti 3+ concentrated stock solution with a flow from the Co 2+ concentrated stock solution and water to provide a mixed electrolyte for electrolessly depositing Co; and
exposing a substrate to the mixed electrolyte for electrolessly depositing Co;
wherein exposing the wafer to the mixed electrolyte for electrolessly depositing Co, comprises:
providing a solution temperature between 20° to 25° C., inclusive; and
providing a pH of between 6 and 10, inclusive.

8. The method, as recited in claim 7 , wherein the cobalt containing layer is at least 99.9% pure cobalt.

9. The method, as recited in claim 7 , wherein the Ti 3+ concentrated stock solution comprises a solution comprising TiCl 3 .

10. The method, as recited in claim 9 , wherein the Co 2+ concentrated stock solution comprises a solution of CoSO 4 and ammonium hydroxide.

11. The method, as recited in claim 10 , wherein the Co 2+ concentrated stock solution has a shelf life of over a month.

12. The method, as recited in claim 11 , wherein the Ti 3+ concentrated stock solution has a shelf life of over a month.

13. The method, as recited in claim 10 , wherein the mixed electrolyte solution is boron, phosphorus, hydrazine, and formaldehyde free.

14. The method, as recited in claim 7 , wherein the mixed electrolyte solution is boron, phosphorus, hydrazine, and formaldehyde free.

15. A method for providing an electroless plating of a cobalt layer, comprising:
providing a solution for electroless deposition of cobalt, comprising:
Ti 3+ ions; and
Co 2+ ions, wherein a ratio of Ti 3+ ions to Co 2+ ions is between 5:1 and 1:5; and

exposing a substrate to the solution for electroless deposition of cobalt, wherein the solution further comprises amine ligands.

16. The method, as recited in claim 15 , wherein the providing the solution, provides the solution at a pH of between 6 and 10, inclusive, and at a temperature between 20° to 25° C., inclusive.

17. The method, as recited in claim 15 , wherein the cobalt layer is at least 99.9% pure cobalt.

18. The method of claim 17 , wherein the solution is boron, phosphorus, hydrazine, and formaldehyde free.

19. The method of claim 15 , wherein the solution is boron, phosphorus, hydrazine, and formaldehyde free.

20. The method as recited in claim 15 , wherein the solution is boron, phosphorus, hydrazine, and formaldehyde free; wherein the cobalt layer is at least 99.9% pure cobalt, and wherein the providing the solution comprises providing the solution at a pH of between 6and 10, inclusive, and at a temperature between 20° to 25° C., inclusive.

Assignees

• Lam Res Corp

Inventors

• Norkus Eugenijus
• Stankeviciene Ina
• Jagminiene Aldona
• Joi Aniruddha
• Tamasauskaite-Tamasiunaite Loreta
• Dordi Yezdi
• Sukackiene Zita

Classifications

• H10P14/46 Primary

  using a liquid · CPC title

• C23C18/31 Primary

  Coating with metals · CPC title

• C23C18/165

  Multilayered product (layered product B32B) · CPC title

• C23C18/34

  using reducing agents · CPC title

• H01L21/288

  Electricity · mapped topic