Multi-Scale Insight into Inhibition Mechanism of Benzo Derivatives in Chemical Mechanical Polishing of Copper Film Based on Experiments and Theoretical Calculations

Abstract

To protect the copper (Cu) surfaces from corrosion during the chemical mechanical polishing (CMP), selecting appropriate inhibitors are critical. Benzo and its derivatives are potential superior inhibitors due to their diverse heteroatoms and environmentally friendliness. In this study, benzothiazole (ABT), 2-benzothiazolamine (2-ABT) and 2-aminobenzimidazole (2-ABI) were used as inhibitors to investigate the effect of molecular structure on the inhibition performance through experimental and theoretical calculation. With the addition of inhibitors, the removal rates were all inhibited effectively and the inhibition efficiency was in the following order: 2-ABI > 2-ABT > ABT. Electrochemical experiments and surface morphology tests demonstrated that the inhibitors could prevent corrosion by forming dense passivation film on Cu surfaces with a high inhibition efficiency of 88%, 94% and 95%, and improve the surface quality after CMP. Calculation results revealed that the introduction of amino groups (–NH2) and nitrogen(N) atom into five-membered ring enhanced the inhibition effect due to the larger adsorption energy, stronger ability to contribute electrons and denser passivation film which consistent with the experiment. Such study confirms the benzimidazole derivatives are potentially inhibitor for Cu film CMP and provides a new reference to design and select novel inhibitors.