Multicomponent Protection at Metal/Oxide Interfaces: Electron-Atomic Scale Mechanism of TT-LYK Inhibitor in Cobalt Chemical Mechanical Polishing

In the chemical mechanical polishing (CMP) of cobalt (Co), surface planarization is critically influenced by the selective adsorption of inhibitor molecules at the metal/oxide interface. Existing studies have confirmed the presence of CoO and Co(OH)2 on cobalt surfaces; however, there has been no investigation into the adsorption behavior of inhibitors on these oxide and hydroxide surfaces. This area remains largely unexplored in the current theoretical research landscape. To date, no studies have systematically investigated the cooperative passivation effects of the TT-LYK inhibitor at metal oxide/hydroxide interfaces, nor have they explored its corrosion inhibition mechanisms across multiple cobalt surface phases. In this study, the adsorption behavior and corrosion inhibition mechanism of the TT-LYK inhibitor at cobalt multiphase interfaces, specifically cobalt monoxide (CoO) and cobalt hydroxide (Co(OH)2), were systematically investigated using density functional theory (DFT) and geometric optimization. Theoretical calculations reveal that TT-LYK exhibits strong chemisorption on both CoO(200) and Co(OH)2(101) surfaces, with adsorption energies reaching −14.1185, −13.6720, −10.1941, and −10.9807 eV, respectively. Electronic structure analysis indicates that TT-LYK forms stable coordination bonds with surface Co2+ ions via its active functional groups, accompanied by significant orbital hybridization and changes in the density of states (DOS). DOS calculations further confirm that TT-LYK adsorption reduces surface reactivity and stabilizes the adsorption configuration. This study provides an atomic-scale explanation of how the inhibitor adsorbs onto the surface of Co oxides and hydroxides, partially isolating the chemical components in the polishing solution from the wafer surface. This helps to slow down undesirable corrosion on the wafer surface, offering a theoretical foundation for the design of high-quality cobalt polishing solutions.