Experimental and Density Functional Theory Study of Inhibitors on Cobalt Corrosion for Chemical Mechanical Planarization Process

Abstract

In the localized and global chemical mechanical planarization (CMP) process of Co barrier layers, corrosion inhibitors play a crucial role in the removal rate (RR) of Co and the post-polishing surface quality. In this study, quantum chemical calculations were employed to investigate the molecular reactivity of benzotriazole (BTA), 5-methyl benzotriazole (TTA), and 2,2’-{[(methyl-1H-benzotriazol-1-yl)methyl]imino}bis-ethanol (TT-LYK), and their inhibitory performance was predicted to follow the order of TT-LYK > TTA > BTA. The experimental results validated the accuracy of the predicted order under static conditions. However, the performance order of the inhibitors shifted to TTA > BTA > TT-LYK due to varying degrees of damage caused by mechanical friction to the inhibitory film. Nevertheless, all three inhibitors are capable of effectively inhibiting the Co RR to meet industrial requirements. Ultimately, considering the outstanding inhibitory performance of TT-LYK and its ease of removal during post-cleaning processes, TT-LYK is determined as the most promising inhibitor for Co barrier layer CMP.