Patent ID: 7988878

Claim:
A solution useful for removing a barrier from a semiconductor substrate, the semiconductor substrate containing tantalum nitride (TaN), copper and carbon-doped oxide (CDO), comprising by weight percent 0.001 to 25 oxidizer, 0.02 to 0.35 anionic surfactant, 0 to 15 inhibitor for a nonferrous metal, 0 to 40 abrasive, 0 to 20 complexing agent for the nonferrous metal, 0.01 to 12 barrier removal agent selected from formamidine, formamidine salts, formamidine derivatives, guanidine, guanidine derivatives, guanidine salts and mixtures thereof; and water; and the solution has an acidic pH and provides a TaN/CDO selectivity of at least 2 to 1 as measured with a microporous polyurethane polishing pad pressure measured normal to a wafer of less than 13.8 kPa.