Investigation on the control effect of benzotriazole and two derivatives on cobalt pitting corrosion in chemical mechanical polishing process: A combination of experiments and theoretical simulations

• The inhibition effect of traditional corrosion inhibitor BTA on cobalt pitting is not ideal. • The molecules of MBTA and TT-LYK have stronger electron donating ability than BTA. • The passivation films formed by MBTA and TT-LYK are more hydrophobic than BTA. • TT-LYK can protect cobalt from pitting in corrosive environmental. As integrated circuits shrink in feature size to 10 nm, the requirements of pitting defects on the cobalt (Co) surface become more stringent during the chemical mechanical polishing of Co interconnects. In this work, the corrosion inhibition effects of benzotriazole (BTA) and its two derivatives, 5-methyl benzotriazole (MBTA) and 2,2′-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bis-Ethanol (TT-LYK) in the slurry at pH 9 were studied by electrochemical methods, contact angle measurement, and scanning electron microscopy (SEM). The adsorption process of the three inhibitors on the cobalt surface could be described by the Langmuir isotherm model. All the azole corrosion inhibitors belong to anodic corrosion inhibitors for Co in a weak alkaline environment. When 8 mM BTA, MBTA and TT-LYK was added to the base solution containing 0.15wt.% glycine and 0.5 wt.% H 2 O 2 , respectively, the corrosion inhibition efficiency reached 87.67%, 92.63% and 95.38%. In addition, the SEM results show that there are almost no pitting defects on the Co surface protected by TT-LYK. Furthermore, the quantum chemical parameters of the three inhibitors were calculated by molecular dynamics and density functional theory. The experimental data support the results of the density functional theory and Molecular dynamic simulation.