Diethylenetriamine and serine as synergists used in FA/OII based alkaline solution to realize enhanced cleaning efficiency of the organic corrosion inhibitor

Abstract

In industrial chemical mechanical polishing (CMP), 5-methyl benzotriazole (MBTA) as a substitute organic inhibitor of benzotriazole has shown great effect in low usage compared to other benzo derivatives. However, it also brings considerable challenges to subsequent post-CMP cleaning due to its hydrophobic property. In this work, diethylenetriamine (DETA) and serine were used as synergists in FA/OII-based alkaline solutions to achieve enhanced removal of MBTA. Contact angle and electrochemical tests proved the weak cleaning performance of FA/OII was generally improved after adding DETA or serine. Especially, 400 ppm serine displayed its superiority with the lowest contact angle and the highest corrosion current density of 24.2° and 1.023 μA/cm2. Then, static observation and X-ray photoelectron spectra analysis confirmed they could break Cu(I)-MBTA and form precipitates like DETA/serine-MBTA. Copper loss after cleaning was also measured by an atomic force microscope and the corresponding surface morphology still needed to be improved by adding proper surfactants. Finally, with the assistance of density functional theory calculation and molecular dynamic simulation, the active sites and reactivity of both reagents were concluded by comparing their intrinsic properties and interaction configurations. Serine turned out to work better than DETA with a lower interaction energy of − 724.83 Kcal/mol.