PLATING SOLUTION FOR ELECTROLESS DEPOSITION OF COPPER

• US 20070261594A1
• Filed: 05/11/2006
• Published: 11/15/2007
• Est. Priority Date: 05/11/2006
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Vaskelis, Algirdas, Jagminiene, Aldona, Norkus, Eugenijus, Jaciauskiene, Jane
• Granted Patent: US 7,306,662 B2
• Time in Patent Office: Days
• US Class Current: 106/1.230
• CPC Class Codes: C23C 18/38 Coating with copper
• CPC Class Codes: C23C 18/48 Coating with alloys

Abstract

An electroless copper plating solution is disclosed herein. The solution includes an aqueous copper salt component, an aqueous cobalt salt component, a triamine based complexing agent, and an acidic pH-modifying substance in an amount sufficient to make the electroless copper plating solution acidic. A method of preparing an electroless copper solution is also provided.

Claims

1. An electroless copper plating solution, comprising:

an aqueous copper salt component;

an aqueous cobalt salt component;

a complexing agent that is a triamine compound; and

a pH-modifying substance in an amount sufficient to make the electroless copper plating solution acidic, wherein, the acidic pH-modifying substance is selected from a group consisting of sulfuric acid, nitric acid, hydrochloric acid, fluoroboric acid, and acetic acid.

2. The electroless copper plating solution, as recited in claim 1, wherein,

the aqueous copper salt component is selected from a group of copper salts consisting of copper(II)sulfate, copper(II)nitrate, copper(II)chloride, copper(II)tetrafluoroborate, and copper(II)acetate.

3. The electroless copper plating solution, as recited in claim 1, wherein,

the aqueous copper salt component is selected from a group of complex copper salts consisting of ethylenediamine copper(II)sulfate, bis(ethylenediamine)copper(II)sulfate, diethylenetriamine copper(II)nitrate, and bis(diethylenetriamine)copper(II)nitrate.

4. The electroless copper plating solution, as recited in claim 1, wherein,

the aqueous cobalt salt component is selected from a group consisting of cobalt(II)sulfate, cobalt(II)nitrate, cobalt(II)chloride, cobalt(II)tetrafluoroborate, and cobalt(II)acetate.

5. The electroless copper plating solution, as recited in claim 1, wherein, the triamine compound is selected from a group consisting of diethylenetriamine, dipropylenetriamine, and ethylene propylenetriamine.

6. The electroless copper plating solution, as recited in claim 1, wherein, a pH of the electroless copper plating solution is between about 4.3 and about 4.6.

7. (canceled)

8. An electroless copper plating solution, comprising:

an aqueous copper salt component having a concentration between about 0.001 molarity (M) to a solubility limit for the aqueous copper salt component;

an aqueous cobalt salt component;

a complexing agent that is a triamine compound; and

a pH-modifying substance in an amount sufficient to make the electroless copper plating solution acidic, wherein the acidic pH-modifying substance is selected from a group consisting of sulfuric acid, nitric acid, hydrochloric acid, fluoroboric acid, and acetic acid.

9. The electroless copper plating solution, as recited in claim 8, wherein the pH-modifying substance is a buffer adjusting the electroless copper plating solution to a pH of between about 4.0 and about 6.4.

10. The electroless copper plating solution, as recited in claim 8, wherein,

the aqueous copper salt component is selected from a group consisting of copper(II)sulfate, copper(II)nitrate, copper(II)chloride, copper(II)tetrafluoroborate, and copper(II)acetate.

11. The electroless copper plating solution, as recited in claim 8, wherein,

the aqueous cobalt salt component is selected from a group consisting of cobalt(II)sulfate, cobalt(II)nitrate, cobalt(II)chloride, cobalt(II)tetrafluoroborate, and cobalt(II)acetate.

12. (canceled)

13. An electroless copper plating solution, comprising:

an aqueous copper salt component;

an aqueous cobalt salt component having a concentration between about 0.001 molarity (M) to a solubility limit for the aqueous cobalt salt component;

a complexing agent that is a triamine compound; and

a pH-modifying substance in an amount sufficient to make the electroless copper plating solution acidic, wherein a pH of the electroless copper plating solution is between about 4.0 and about 6.4.

15. The electroless copper plating solution, as recited in claim 13, wherein, the aqueous copper salt component is selected from a group consisting of copper(II)sulfate, copper(II)nitrate, copper(II)chloride, copper(II)tetrafluoroborate, and copper(II)acetate.

16. The electroless copper plating solution, as recited in claim 13, wherein, the aqueous cobalt salt component is selected from a group consisting of cobalt(II)sulfate, cobalt(II)nitrate, cobalt(II)chloride, cobalt(II)tetrafluoroborate, and cobalt(II)acetate.

14. (canceled)

17. An electroless copper plating solution, comprising:

an aqueous copper salt component;

an aqueous cobalt salt component;

a complexing agent that is a triamine compound, wherein the complexing agent has a concentration between about 0.005 molarity (M) to about 10.0M; and

a pH-modifying substance in an amount sufficient to make the electroless copper plating solution acidic, wherein a pH of the electroless copper plating solution is between about 4.0 and about 6.4.

18. The electroless copper plating solution, as recited in claim 17, wherein, the electroless copper plating solution is prepared by mixing a first mixture with a second mixture, wherein,

the first mixture consists essentially of the aqueous copper salt component, the pH modifying substance, and a portion of the complexing agent;

and

the second mixture consists essentially of the aqueous cobalt salt component and a remainder of the complexing agent.

19. The electroless copper plating solution, as recited in claim 17, wherein, the electroless copper plating solution is prepared by sequentially combining the aqueous copper salt component to a volume of water, then adding the pH-modifying substance to the aqueous copper salt component/water combination, thereafter adding the complexing agent, and lastly adding the aqueous cobalt salt component.

20. A method for preparing an electroless copper plating solution comprising:

combining an aqueous copper salt component, a portion of a complexing agent and an acid as a first component;

combining an aqueous cobalt salt component and a remaining portion of the complexing agent as a second component; and

mixing the first component and the second component prior to use in a deposition operation.

21. The method for preparing an electroless copper plating solution, as recited in claim 20, wherein,

the aqueous copper salt component is selected from a group consisting of copper(II)sulfate, copper(II)nitrate, copper(II)chloride, copper(II)tetrafluoroborate, and copper(II)acetate.

22. The method for preparing an electroless copper plating solution, as recited in claim 20, wherein,

the aqueous cobalt salt component is selected from a group consisting of cobalt(II)sulfate, cobalt(II)nitrate, cobalt(II)chloride, cobalt(II)tetrafluoroborate, and cobalt(II)acetate.

23. The method for preparing an electroless copper plating solution, as recited in claim 20, wherein, the complexing agent is a triamine compound.