Anti-tarnish coatings

• US 7,972,655 B2
• Filed: 11/21/2007
• Issued: 07/05/2011
• Est. Priority Date: 11/21/2007
• Status: Active Grant

• Current Assignee: MacDermid Enthone Inc. (Element Solutions Inc)
• Original Assignee: Enthone Incorporated (Element Solutions Inc)
• Inventors: Sun, Shenliang, Antonellis, Theodore, Abys, Joseph A.
• Primary Examiner(s): CAMERON, ERMA C
• Application Number:
  US11/944,287
• Publication Number:
  US 20100291303A1
• Time in Patent Office: 1,322 Days
• Field of Search: None
• US Class Current: 427/337
• CPC Class Codes: C08K 5/17 Amines; Quaternary ammonium compounds
• CPC Class Codes: C08K 5/37 Thiols
• CPC Class Codes: C09D 5/086 Organic or non-macromolecular compounds
• CPC Class Codes: C09D 7/45 Anti-settling agents
• CPC Class Codes: C09D 7/63 organic
• CPC Class Codes: C23C 18/54 Contact plating, i.e. electroless electrochemical plating
• 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: C23F 11/161 Mercaptans
• 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

Abstract

A method is disclosed for enhancing the corrosion resistance of a surface of a copper or copper alloy substrate. The method comprises depositing a metallic surface layer comprising a precious metal on a surface of the copper or copper alloy substrate by immersion displacement plating and exposing the electronic device to an aqueous composition comprising a first organic molecule comprising at least one functional group that interacts with and protects precious metal surfaces and a second organic molecule comprising at least one functional group that interacts with and protects copper surfaces.

Claims

1. A method for enhancing the corrosion resistance of a surface of a copper or copper alloy substrate, the method comprising:

depositing a metallic surface layer comprising a precious metal on the surface of the copper or copper alloy substrate; and

exposing the copper or copper alloy substrate having the metallic surface layer thereon to an aqueous composition comprising (a) a first organic molecule comprising at least one functional group that interacts with and protects precious metal surfaces, said first molecule being elected from the group consisting of thiols (mercaptans), disulfides, thioethers, thioaldehydes, thioketones, and combinations thereof, (b) a second organic molecule comprising at least one functional group that interacts with and protects copper surfaces, said second molecule being elected from the group consisting of primary amines, secondary amines, tertiary amines, aromatic heterocycles comprising nitrogen, and combinations thereof and (c) a surfactant.

2. The method of claim 1 wherein the metallic surface layer is deposited by an immersion displacement plating process, and the metallic surface layer comprises silver, gold, or a combination thereof.

3. The method of claim 1 wherein the first organic molecule is a thiol having the following general structure (I):

R₁—

S—

H 

 

Structure (I)

wherein R₁ is either a hydrocarbyl having between one carbon atom and about 24 carbon atoms or an aryl having between about five and about fourteen carbon atoms.

4. The method of claim 3 wherein the thiol is selected from the group consisting of ethanethiol;

1-propanethiol;

2-propanethiol;

2-propene-1-thiol;

1-butanethiol;

2-butanethiol;

2-methyl-1-propanethiol;

2-methyl-2-propanethiol;

2-methyl-1-butanethiol;

1-pentanethiol;

2,2-dimethyl-1-propanethiol;

1-hexanethiol;

1,6-hexanedithiol;

1-heptanethiol;

2-ethylhexanethiol;

1-octanethiol;

1,8-octanedithiol;

1-nonanethiol;

1,9-nonanedithiol;

1-decanethiol;

1-adamantanethiol;

1,11-undecanedithiol;

1-undecanethiol;

1-dodecanethiol;

tert-dodecylmercaptan;

1-tridecanethiol;

1-tetradecanethiol;

1-pentadecanethiol;

1-hexadecanethiol;

1-heptadecanethiol;

1-octadecanethiol;

1-nonadecanethiol; and

1-icosanethiol; and

combinations thereof.

5. The method of claim 3 wherein the thiol is selected from the group consisting of benzenethiol;

2-methylbenzenethiol;

3-methylbenzenethiol;

4-methylbenzenethiol;

2-ethylbenzenethiol;

3-ethylbenzenethiol;

4-ethylbenzenethiol;

2-propylbenzenethiol;

3-propylbenzenethiol;

4-propylbenzenethiol;

2-tert-butylbenzenethiol;

4-tert-butylbenzenethiol;

4-pentylbenzenethiol;

4-hexylbenzenethiol;

4-heptylbenzenethiol;

4-octylbenzenethiol;

4-nonylbenzenethiol;

4-decylbenzenethiol;

benzyl mercaptan;

2,4-xylenethiol, furfuryl mercaptan;

1-naphthalenethiol;

2-naphthalenethiol;

4,4′

-dimercaptobiphenyl; and

combinations thereof.

6. The method of claim 1 wherein the first organic molecule is a disulfide having the following structure (II):

R₁—

S—

S—

R₂ 

 

Structure (II)

wherein R₁ and R₂ are each independently either a hydrocarbyl having between one carbon atom and about 24 carbon atoms or an aryl having between about five and about fourteen carbon atoms.

7. The method of claim 6 wherein the disulfide is selected from the group consisting of diethyl disulfide, di-n-propyl disulfide, diisopropyl disulfide, diallyl disulfide, di-n-butyl disulfide, di-sec-butyl disulfide, diisobutyl disulfide, di-tert-butyl disulfide, di-n-pentyl disulfide, di-neopentyl disulfide, di-n-hexyl disulfide, di-n-heptyl disulfide, di-n-octyl disulfide, di-n-nonyl disulfide, di-n-decyl disulfide, di-n-dodecyl disulfide, di-n-tridecyl disulfide, di-n-tetradecyl disulfide, di-n-pentadecyl disulfide, di-n-hexadecyl disulfide, di-n-heptadecyl disulfide, di-n-octadecyl disulfide, di-n-decyl disulfide;

diundecyl disulfide, didodecyl disulfide, dihexadecyl disulfide, dibenzyl disulfide, dithienyl disulfide, 2-naphthyl disulfide, and combinations thereof.

8. The method of claim 1 wherein the second organic molecule is a primary amine, secondary amine, or a tertiary amine having the following general structure (III):

9. The method of claim 8 wherein the amine is selected from the group consisting of aminoethane, 1-aminopropane, 2-aminopropane, 1-aminobutane, 2-aminobutane, 1-amino-2-methylpropane, 2-amino-2-methylpropane, 1-aminopentane, 2-aminopentane, 3-aminopentane, neo-pentylamine, 1-aminohexane, 1-aminoheptane, 2-aminoheptane, 1-aminooctane, 2-aminooctane, 1-aminononane, 1-aminodecane, 1-aminododecane, 1-aminotridecane, 1-aminotetradecane, 1-aminopentadecane, 1-aminohexadecane, 1-aminoheptadecane, 1-aminooctadecane, and combinations thereof.

10. The method of claim 1 wherein the second organic molecule is an azole having the following aeneral structure (IV):

11. The method of claim 10 wherein the azole is selected from the group consisting of pyrrole (1H-azole);

imidazole (1,3-diazole);

pyrazole (1,2-diazole);

1,2,3-triazole;

1,2,4-triazole;

tetrazole;

isoindole;

indole (1H-benzo[b]pyrrole);

benzimidazole (1,3-benzodiazole);

indazole (1,2-benzodiazole);

1H-benzotriazole;

2H-benzotriazole;

imidazo[4,5-b]pyridine;

purine (7H-imidazo (4,5-d)pyrimidine);

pyrazolo[3,4-d]pyrimidine;

triazolo[4,5-d]pyrimidine; and

combinations thereof.

12. The method of claim 10 wherein the azole is selected from the group consisting of 2-(3,4-dichlorobenzyl)-benzimidazole;

2-bromobenzyl benzimidazole;

2-bromophenyl benzimidazole;

2-bromoethylphenyl benzimidazole;

2-chlorobenzyl benzimidazole;

2-chlorophenyl benzimidazole;

2-chloroethylphenyl benzimidazole; and

combinations thereof.

13. The method of claim 1 wherein the first organic molecule is present in a concentration between about 1 and about 10 g/L and the second organic molecule in a concentration between about 1 and about 10 g/L.

14. A process as set forth in claim 1 wherein said composition comprises an aqueous solution having a pH between about 7.0 and about 11.0.

15. A method for enhancing the corrosion resistance of a surface of a copper or copper alloy substrate, the method comprising:

depositing a metallic surface layer comprising silver and/or gold on the surface of the copper or copper alloy substrate; and

exposing the copper or copper alloy substrate having the metallic surface layer thereon to an aqueous composition comprising (a) a first organic molecule in a concentration between about 1 and about 10 g/L selected from the group consisting of thiols (mercaptans), disulfides, thioethers, thioaldehydes, thioketones, and combinations thereof that interacts with and protects precious metal surfaces, (b) a second organic molecule in a concentration between about 1 and about 10 g/L selected from the group consisting of primary amines, secondary amines, tertiary amines, aromatic heterocycles comprising nitrogen, and combinations thereof that interacts with and protects copper surfaces, and (c) a surfactant.

16. A process as set forth in claim 15 wherein said composition comprises an aqueous solution having a pH between about 7.0 and about 11.0.

17. A method for enhancing the corrosion resistance of a surface of a copper or copper alloy substrate, the method comprising:

depositing a metallic surface layer comprising silver and/or gold on the surface of the copper or copper alloy substrate; and

exposing the copper or copper alloy substrate having the metallic surface layer thereon to an aqueous composition comprising (a) a first organic molecule of 1-octadecanethiol in a concentration between about 1 and about 10 g/L, (b) a second organic molecule in a concentration between about 1 and about 10 g/L selected from the group consisting of primary amines, secondary amines, tertiary amines, aromatic heterocycles comprising nitrogen, and combinations thereof that interacts with and protects copper surfaces, and (c) a surfactant.

18. A process as set forth in claim 17 wherein said composition comprises an aqueous solution having a pH between about 7.0 and about 11.0.