Electroplating composition intended for coating a surface of a substrate with a metal

• US 20070062818A1
• Filed: 11/04/2005
• Published: 03/22/2007
• Est. Priority Date: 09/20/2005
• Status: Abandoned Application

• Current Assignee: Alchimer S.A.
• Original Assignee: Alchimer S.A.
• Inventors: Gonzalez, Jose, Daviot, Jerome
• Application Number:
  US11/266,799
• Publication Number:
  US 20070062818A1
• Time in Patent Office: Days
• US Class Current: 205/291
• CPC Class Codes: C25D 3/38 of copper
• CPC Class Codes: C25D 5/34 Pretreatment of metallic surfaces to be electroplated
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76873 for electroplating

Abstract

The object of the present invention is an electroplating composition intended in particular for coating a copper-diffusion barrier layer in the fabrication of interconnects for integrated circuits. According to the invention, this composition comprises, in solution in a solvent: a source of copper ions, in a concentration of between 0.4 and 40 mM; at least one copper complexing agent chosen from the group comprising primary aliphatic amines, secondary aliphatic amines, tertiary aliphatic amines, aromatic amines, nitrogen heterocycles and oximes; the copper/complexing agent(s) molar ratio being between 0.1 and 2.5, preferably between 0.3 and 1.3; and the pH of the said composition being less than 7, preferably between 3.5 and 6.5.

Claims

1. Electroplating composition intended in particular for coating a copper-diffusion barrier layer in the fabrication of interconnects for integrated circuits, characterized in that it comprises, in solution in a solvent:

a source of copper ions, in a concentration of between 0.4 and 40 mM;

at least one copper complexing agent chosen from the group comprising primary aliphatic amines, secondary aliphatic amines, tertiary aliphatic amines, aromatic amines, nitrogen heterocycles and oximes;

the copper/complexing agent(s) molar ratio being between 0.1 and 2.5, preferably between 0.3 and 1.3; and

the pH of the said composition being less than 7, preferably between 3.5 and 6.5.

2. Electroplating composition according to claim 1, wherein the abovementioned solvent is chosen from water and hydroalcoholic mixtures.

3. Electroplating composition according to claim 1, wherein the aforementioned source of copper ions is a copper salt, such as in particular copper sulphate, copper chlorate, copper nitrate or copper acetate, preferably copper sulphate.

4. Electroplating composition according to claim 1, wherein the aforementioned copper complexing agent is chosen from:

primary aliphatic amines, in particular ethylamine, cyclohexylamine, ethylenediamine and cyclohexanediamine;

secondary aliphatic amines, in particular pyrrolidine;

tertiary aliphatic amines, in particular hydroxyethyldiethylamine and tetraethylenepentamine;

aromatic amines, in particular 1,2-diaminobenzene and 3,5-dimethylaniline;

nitrogen heterocycles, in particular pyridine, 2,2′

-bipyridine, 8-hydroxyquinoline sulphonate, 1,10-phenanthroline, 3,5-dimethylpyridine and 2,2′

-bipyrimidine; and

oximes, in particular dimethylglyoxime.

5. Electroplating composition according to claim 1, wherein the aforementioned copper complexing agent is a nitrogen heterocycle chosen from pyridine, 2,2′

-bipyridine, 8-hydroxyquinoline sulphonate, 1,10-phenanthroline, 3,5-dimethylpyridine and 2,2′

-bipyrimidine.

6. Electroplating composition according to claim 1, wherein it comprises a mixture of pyridine and 2,2′

-bipyridine as copper complexing agents.

7. Electroplating composition according to claim 6, wherein it comprises, in aqueous solution:

copper sulphate, with a concentration of between 0.4 and 40 mM;

a mixture of pyridine and 2,2′

-bipyridine as copper complexing agents;

the copper/complexing agents molar ratio being between 0.3 and 1.3; and

the pH of the said composition being less than 7, preferably between 3.5 and 6.5.

8. Use of an electroplating composition according to claim 1 for coating a copper-diffusion barrier layer in the fabrication of interconnects for integrated circuits.