SELF ASSEMBLED MOLECULES ON IMMERSION SILVER COATINGS

• US 20090121192A1
• Filed: 11/10/2008
• Published: 05/14/2009
• Est. Priority Date: 11/08/2007
• Status: Active Grant

• Current Assignee: MacDermid Enthone Inc. (Element Solutions Inc)
• Original Assignee: Enthone Incorporated (Element Solutions Inc)
• Inventors: Abys, Joseph A., Sun, Shenliang, Antonellis, Theodore
• Granted Patent: US 8,216,645 B2
• Time in Patent Office: Days
• US Class Current: 252/392
• CPC Class Codes: C23C 22/02 using non-aqueous solutions
• CPC Class Codes: C23F 11/08 in other liquids
• CPC Class Codes: C23F 11/10 using organic inhibitors
• CPC Class Codes: C23F 11/149 Heterocyclic compounds containing nitrogen as hetero atom
• CPC Class Codes: H05K 2203/122 Organic non-polymeric compounds, e.g. oil, wax, thiol using solvent H05K2203/0783
• CPC Class Codes: H05K 2203/124 Heterocyclic organic compounds, e.g. azole, furan
• CPC Class Codes: H05K 3/244 Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473
• CPC Class Codes: H05K 3/282 for inhibiting the corrosion of the circuit, e.g. for preserving the solderability
• CPC Class Codes: Y10T 428/12556 Organic component

Abstract

A method for enhancing the corrosion resistance of an article comprising a silver coating deposited on a solderable copper substrate is provided. The method comprises exposing the copper substrate having the immersion-plated silver coating thereon to an anti-corrosion composition comprising: a) a multi-functional molecule comprising at least one organic functional group that interacts with and protects copper surfaces and at least one organic functional group that interacts with and protects silver surfaces; b) an alcohol; and c) a surfactant.

Claims

1. A method for enhancing the corrosion resistance of an article comprising a silver coating deposited on a solderable copper substrate, the method comprising:

exposing the copper substrate having the silver coating thereon to an anti-corrosion composition comprising;

a multi-functional molecule, wherein the multi-functional molecules comprises at least one nitrogen-containing organic functional group that interacts with and protects copper surfaces and at least one sulfur-containing organic functional group that interacts with and protects silver surfaces;

an alcohol;

a surfactant; and

an alkaline pH adjuster.

2. The method of claim 1 wherein the nitrogen-containing functional group comprises an amine.

3. The method of claim 1 wherein the nitrogen-containing functional group comprises one of a primary amine, secondary amine, tertiary amine, or aromatic heterocycle.

4. The method of claim 1 wherein the nitrogen-containing functional group comprises an azole.

5. The method of claim 1 wherein the nitrogen-containing functional group comprises a benzimidazole.

6. The method of claim 1 wherein the sulfur-containing functional group comprises one of a thiol, disulfide, thioether, thioaldehyde, thioketone, or aromatic heterocycle.

7. The method of claim 3 wherein the sulfur-containing functional group comprises one of a thiol, disulfide, thioether, thioaldehyde, thioketone, or aromatic heterocycle.

8. The method of claim 5 wherein the sulfur-containing functional group comprises one of a thiol, disulfide, thioether, thioaldehyde, thioketone, or aromatic heterocycle.

9. The method of claim 1 wherein the sulfur-containing functional group comprises a thiol.

10. The method of claim 1 wherein the sulfur-containing functional group comprises a disulfide.

11. The method of claim 1 wherein the multi-functional molecule comprises azole and thiol functional groups.

12. The method of claim 1 wherein the multi-functional molecule has one of the following structures:

wherein R₁ is hydrocarbyl and R₂, R₃, and R₄ are nitrogen, sulfur, or carbon;

the carbon chain of the hydrocarbyl comprises between two and about 24 carbon atoms; and

any of the carbon chain of the hydrocarbyl, R₂, R₃, and R₄ may be substituted or unsubstituted.

13. The method of claim 3 wherein the multi-functional molecule has one of the following structures:

wherein R₁ is hydrocarbyl and R₂, R₃, and R₄ are nitrogen, sulfur, or carbon;

the carbon chain of the hydrocarbyl comprises between two and about 24 carbon atoms; and

any of the carbon chain of the hydrocarbyl, R₂, R₃, and R₄ may be substituted or unsubstituted.

14. The method of claim 5 wherein the multi-functional molecule has one of the following structures:

wherein R₁ is hydrocarbyl and R₂, R₃, and R₄ are nitrogen, sulfur, or carbon;

the carbon chain of the hydrocarbyl comprises between two and about 24 carbon atoms; and

any of the carbon chain of the hydrocarbyl, R₂, R₃, and R₄ may be substituted or unsubstituted.

15. The method of claim 1 wherein the alcohol is present in a concentration between about 10 mL/L and about 500 mL/L.

16. The method of claim 1 wherein the surfactant is non-ionic.

17. The method of claim 1 wherein the multi-functional molecule is present in a concentration between about 0.1 g/L and about 10 g/L.

18. The method of claim 1 wherein:

the alcohol is present in a concentration between about 10 mL/L and about 500 mL/L;

the surfactant is non-ionic and present in a concentration between about 0.01 g/L and about 2 g/L; and

the multi-functional molecule is present in a concentration between about 0.1 g/L and about 10 g/L.

19. The method of claim 1 wherein:

the alcohol is present in a concentration between about 10 mL/L and about 500 mL/L;

the surfactant is non-ionic and present in a concentration between about 0.01 g/L and about 2 g/L; and

the multi-functional molecule is present in a concentration between about 0.1 g/L and about 10 g/L.

20. The method of claim 1 wherein the composition is free of alkali metal hydroxide.

21. A composition for enhancing the corrosion resistance of an article comprising a silver coating deposited on a solderable copper substrate, the composition comprising:

a multi-functional molecule, wherein the multi-functional molecules comprises at least one nitrogen-containing organic functional group that interacts with and protects copper surfaces and at least one sulfur-containing organic functional group that interacts with and protects silver surfaces;

an alcohol;

a surfactant; and

an alkaline pH adjuster.