Gold CMP composition and method

1. A cyanide-free chemical-mechanical polishing (CMP) composition for polishing a gold-containing surface of a substrate comprising:

(a) an abrasive;

(b) a gold-oxidizing agent;

(c) a cyanide-free gold-solubilizing agent comprising a phosphonic acid chelating agent, a salt thereof, or a combination thereof; and

(d) an aqueous carrier therefor;

and wherein the cyanide-free gold-solubilizing agent is present in the composition at a concentration in the range of about 0.5% to about 6% on a weight basis.

2. The CMP composition of claim 1 wherein the gold oxidizing agent is present in the composition at a concentration in the range of about 0.5% to about 6% on a weight basis.

3. The CMP composition of claim 1 wherein the composition has a basic pH and the gold-oxidizing agent comprises a persulfate salt.

4. The CMP composition of claim 1 wherein the composition has an acidic pH and the gold-oxidizing agent comprises a halogen.

5. The CMP composition of claim 1 wherein the composition has an acidic pH and the gold-oxidizing agent comprises a reactive admixture of an oxyhalogen compound and a halide salt.

6. The CMP composition of claim 5 wherein the admixture of an oxyhalogen compound and a halide salt is selected from the group consisting of:

(a) an iodate compound admixed with an iodide salt,

(b) a bromate compound admixed with a bromide salt, and

(c) a chlorate compound admixed with a chloride salt.

7. The CMP composition of claim 5 wherein the gold-oxidizing agent comprises an admixture of an iodate compound and an iodide salt, the iodate compound being present in the composition at an initial concentration of about 2% by weight and the iodide salt being present in the composition at an initial concentration of about 2% by weight.

8. The CMP composition of claim 1 wherein the phosphonic acid chelating agent comprises amino-tris(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, or a combination thereof.

9. The CMP composition of claim 1 wherein the abrasive is present in the composition at a concentration in the range of about 0.1% to about 3% on a weight basis.

10. The CMP composition of claim 1 wherein the abrasive comprises alpha-alumina.

11. The CMP composition of claim 1 wherein the cyanide-free gold-solubilizing agent comprises a phosphonic acid chelating agent, the gold-oxidizing agent is ammonium persulfate, and the composition has a basic pH.

12. The CMP composition of claim 11 wherein the composition has a pH of about 9.