In-situ specyroscopic ellipsometry of the Cu surfaces in benzotriazole-hydrogen (BTA-H2O2) solutions using micro flow cell

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 (C6H5N3)-H2O2 aqueous solutions was studied by using in-situ spectroscopic ellipsometry. A rapid flow cell was used and initial changes in an ellipsometric parameter, Δ, which corresponds to the layer thickening, were discussed. BTA forms a passivation layer and the oxidation from H2O2 precedes that.