Investigations were carried out to understand the effect of hydrogen peroxide as an oxidant and benzotriazole (BTA) as an inhibitor on the chemical mechanical planarization (CMP) of copper. Cu-CMP was studied using electrochemistry and removal rate measurements in solutions containing the oxidizer and the inhibitor. In the presence of 0.1 M glycine, the copper removal rate was high in the solution containing 5% H2O2 at pH 2 because of a Cu-glycine complexation reaction. The dissolution rate of Cu increased due to the formation of the highly soluble Cu-glycine complex in the presence of hydrogen peroxide. Addition of 0.01 M BTA in the solution containing 0.1 M glycine and 5% H2O2 at pH 2 exhibited a reduction in the Cu removal rate by the formation of a Cu-BTA complex on the surface of copper that inhibits the dissolution. X-ray photoelectron spectroscopy and secondary-ion mass spectroscopy investigations revealed the formation of a Cu-glycine complex, which aided the understanding of the mechanism of Cu-oxidant-inhibitor interaction during polishing. (C) 2004 The Electrochemical Society.