Abstract
During Cu CMP, Cu surface is oxidized by an oxidizer or a complexiation reagent. To inhibit oxidation, a corrosion inhibitor is co-added in the slurry. Balancing oxidation and surface passivation is of importance in advanced Cu CMP. Layer formation onto clean Cu surfaces in BTA (C_6H_5N_3)-H_2O_2 aqueous solutions was studied by using in-situ spectroscopic ellipsometry. Time changes in an ellipsometric parameter, Δ, which corresponds to the layer thickening, were discussed with respect to BTA and H_2O_2 concentrations. BTA forms a passivation layer and the oxidation from H_2O_2 precedes that. Too high addition of BTA accelerates the layer formation. Competition between oxidation and passivation is discussed.
