Benzohydroxamic Acid Inhibitor for Cu Chemical Mechanical Polishing Achieves Superior Surface Quality with Minor Removal Rate Reduction

Inhibitors are critical for obtaining superior surface quality during copper chemical mechanical polishing (Cu CMP), However, under low-pressure CMP, traditional inhibitors significantly compromises the Cu removal rate, presenting a challenge to balance surface quality and removal rate. To address this challenge, this study employed benzohydroxamic acid (BA) as an inhibitor for Cu CMP. CMP experiments demonstrated that using 0.5 wt% BA significantly decreased the surface roughness parameter Sq from 5.21 to 0.77 nm, while the Cu removal rate reduced slightly from 651.3 Å min −1 to 560.0 Å min −1 . BA exhibited a superior inhibition efficiency of 92.3% at a 0.5 wt% BA, which was due to the mixed adsorption of BA. Moreover, the result of DFT calculation revealed that the O1 and O2 atoms in BA are the active adsorption sites. Adsorption model calculations confirmed that parallel adsorption of BA contributes more to corrosion inhibition than vertical adsorption. In addition to studying the adsorption process of the BA molecule on Cu surfaces, this paper also studies the reaction process between BA and free Cu ions in solutions, as well as the adsorption behavior of the insoluble BA-Cu 2+ complex on Cu surfaces. Overall, this paper provided valuable insights into the investigation of Cu inhibitors.