Patent ID: 7842192

Claim:
A polishing solution useful for removing barrier materials in the presence of at least one nonferrous interconnect metal with limited erosion of dielectrics comprising: 0 to 20 weight percent oxidizer, at least 0.001 weight percent inhibitor for reducing removal rate of the nonferrous interconnect metals, 1 ppm to 4 weight percent organic-containing ammonium cationic salt formed with wherein the ammonium cationic salt is selected from at least one of tetrabutylammonium salts, benzyltributylammonium salts, benzyltrimethylammonium salts, benzyltriethylammonium salts and mixtures thereof, 1 ppm to 4 weight percent anionic surfactant for increasing removal rate of carbon-doped oxide, the anionic surfactant having 4 to 25 carbon atoms and the total carbon atoms of the ammonium cationic salt plus the anionic surfactant being 6 to 40 carbon atoms, 0 to 50 weight percent abrasive and balance water; and the solution having a pH of less than 5 with a tantalum nitride to copper selectivity of at least a 1 to 1 ratio as measured in Angstroms per minute with a polishing pad pressure normal to a wafer less than 15 kPa and with a tantalum nitride to carbon-doped oxide selectivity of a 1 to 2 ratio to a 10 to 1 ratio as measured in Angstroms per minute with the polishing pad pressure normal to the wafer less than 15 kPa.