Azoles as corrosion inhibitors in alkaline medium for ruthenium chemical mechanical planarization applications:Electrochemical and theoretical analysis

The adsorption performance and inhibition mechanism of azoles; Imidazole (IMD), 1, 2, 4-Triazole (TAZ), and 1, 2, 3-Benzotriazole (BTAH) inhibitors on ruthenium (Ru) at 9 pH, were investigated in this study using electrochemical techniques and density functional theory (DFT) simulations. The electrochemical data demonstrate that the three azole compounds being investigated are mixed type corrosion inhibitors with anodic predominance, and the order of corrosion inhibition efficiency for Ru is BTAH > TAZ > IMD. The azole compounds suppress the metal dissolution reaction rate by adhering on to the Ru surface and nature of adsorption (combined physisorption and chemisorption) is explained via Langmuir adsorption isotherm model. The increase in contact angle on the Ru surface verified the successful adsorption of the three organic inhibitors on the Ru surface. Furthermore, the suppression of corrosion reaction kinetics is validated with field emission scanning electron microscopy (FESEM) images. The results of quantum chemistry calculations indicate that the corrosion inhibition effect of BTAH is superior to that of IMD and TAZ. Further, using molecular dynamics modelling, the reliable configuration of the organic inhibitor molecules on the Ru (001) surface in aqueous medium was investigated and the total adsorption energy was computed.