The synergistic inhibitory effect and density functional theory study of 2,2′-[[(Methyl-1H-benzotriazol-1-yl)methyl]imino] bisethanol and potassium oleate on copper in H2O2 based alkaline slurries

Copper (Cu), during the chemical mechanical polishing (CMP) of barrier layer, was associated with several challenges, one of which is to screen slurries required to address the corrosion of Cu. A large number of CMP studies have proved the effectiveness of inhibitors on Cu, but the passivation mechanism is not clear from the perspective of atoms, which needs further confirmation by computational chemistry. In this study, 2,2'-[[(Methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol (TT-LYK) and potassium oleate (PO) as inhibitors for Cu were widely investigated by experimental and density functional theory (DFT) methods. The CMP experiments and potentiodynamic polarization data showed that both of them were mixed (-) type corrosion inhibitors with significant corrosion inhibition ability on Cu. Besides, the combination of TT-LYK and PO exhibited excellent performance in suppressing the Cu corrosion, which were well prove by the surface morphology, single frequency electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) measurements. In addition, DFT calculation show that TT-LYK and PO were adsorbed on the Cu surface by the Cu-N bonds and Cu-O bonds at the bridge site, respectively, thereby obtaining the most stable configuration. This work is conducive to elucidate the role of corrosion inhibitors from a micro level.