Novel tetrazole inhibitors for alkaline Cu-CMP: Experimental and theoretical studies

Abstract

Corrosion inhibitors are vital in chemical mechanical polishing (CMP) to control excessive corrosion. Since conventional corrosion inhibitors fail to adapt to alkaline polishing processes, the search for new corrosion inhibitors has become a pressing issue. This study investigates two novel tetrazole compounds, tetrazole (TEZ) and 5-methyl-1H-tetrazole (MTEZ), as corrosion inhibitors in alkaline CMP slurry, with 1,2,4-triazole (TAZ) serving as a comparative agent. Polishing experiments demonstrate that the copper material removal rate of TEZ achieves 881 nm/min. Electrochemical experiments and surface characteristic analysis show that the order of corrosion inhibition efficiency is TEZ > MTEZ > TAZ. The inhibition efficiency of TEZ, MTEZ and TAZ at 10 mM reach 97.6%, 93.1% and 85.5%, respectively. DFT calculations and molecular dynamics simulations reveal that TEZ exhibits superior reactivity, and the steric hindrance from methyl substitution attenuates this property in MTEZ.