First-principles Insight into the PH-dependency of the Corrosion Inhibition Ability of Benzotriazole and 1,2,4-Triazole for Copper in Chemical Mechanical Polishing Slurry

A comprehensive set of first-principles calculations was conducted to elucidate the disparity and pH-dependency of the corrosion inhibition performance of benzotriazole and 1,2,4-triazole in copper chemical mechanical polishing (CMP) slurry. Unlike previous calculations adopted the simplified and rigid model with neutral molecules adsorbed on metallic copper surface, the models, including Cu and Cu2O surfaces covered with O or -OH species, as well as neutral and deprotonated forms of inhibitor molecules, were constructed to simulate the adsorption interface based on the experimental results. The calculated adsorption energy successfully explained the pH-dependency of the inhibition ability of the two inhibitors.