Molecular interactions of amino acids for corrosion control in molybdenum CMP through bridging experimental insights and DFT simulations

As semiconductor devices scale below the 3 nm node, Mo is a promising replacement for Cu due to its superior electromigration resistance and lower diffusivity in dielectric layers. However, controlling Mo corrosion during chemical mechanical planarization (CMP) remains challenging. This study explores eco-friendly amino acids, including glycine, aspartic acid, arginine, histidine, and methionine, as corrosion inhibitors in acidic slurries, focusing on the roles of their functional groups. Electrochemical analyses show that amino acids with strong electron-donating groups (arginine, histidine, and methionine) effectively suppress Mo ion dissolution. Density functional theory calculations confirm their stable adsorption onto MoO₂ surfaces, with the guanidinium group in arginine and the thioether group in methionine enhancing adsorption energies and stabilizing the Mo surface. X-ray photoelectron spectroscopy reveals that electron-donating amino acids preserve Mo⁰ states, mitigating corrosion under oxidizing conditions. Arginine provides strong corrosion protection but reduces the material removal rate (MRR), while methionine achieves a balance by reducing the static etch rate to 26 Å/min and maintaining an MRR of 255 Å/min. These findings demonstrate the potential of biodegradable, electron-rich amino acids as sustainable inhibitors for Mo CMP. Optimization of molecular structures enables corrosion control, improved removal efficiency, and environmentally friendly semiconductor processing.