Chemical mechanical polishing of copper has been conducted using Fe(NO3)(3) as the copper etchant, benzotriazole (BTA) as the inhibitor, and gamma -alumina particles as the abrasives. The dishing effects were evaluated for the slurries containing various Fe(NO3)(3) and BTA concentrations. Copper dishing increases dramatically with Fe(NO3)(3) concentration in the absence of BTA. BTA reduces copper dishing significantly when BTA concentration is increased. No significant improvement in copper dishing reduction has been observed when the BTA concentration is higher than 0.005 mol/dm(3). The copper polishing process is not successful at high Fe(NO3)(3) concentrations in the absence of BTA. However, a BTA concentration of 0.005 mol/dm(3) or higher in the slurry formulation can lead to a reliable implementation of the acidic copper polishing process.