Polishing Copper-Containing patterned wafers

A method for polishing a patterned semiconductor wafer containing a copper interconnect metal with a polishing pad including the steps of:

• a. providing an aqueous polishing solution, the polishing solution containing an benzotriazole (BTA) inhibitor and a complexing compound of a formula as follows:
• where R is hydrogen or a carbon-containing compound, the complexing compound being capable of complexing copper ions and water;
• b. polishing the patterned wafer with the aqueous polishing solution and the polishing pad in a manner that dissolves copper into Cu+1 ions, the Cu+1 ions and BTA inhibitor having a concentration where [BTA]*[Cu+1]>than Ksp for Cu-BTA precipitate if the aqueous solution did not contain the complexing compound;
• and
• c. oxidizing at least some of the Cu+1 ions to Cu+2 ions to prevent the polishing from precipitating the Cu-BTA precipitate on the patterned wafer and polishing pad.