Substituent Electronic Effects of C5-Substituted Benzotriazole Derivatives on Copper Nanostructure Corrosion Inhibition in Chemical Mechanical Planarization

Although benzotriazole (BTA) and its derivatives represent the predominant corrosion inhibitors used in copper chemical mechanical planarization (CMP), the substituent electronic effects on corrosion inhibition performance have not been fully elucidated. This study systematically examines the structure–property correlation of C5-substituted BTA derivatives in copper CMP through a combined approach of theoretical simulations, electrochemical measurements, and practical CMP testing. Results indicate that both NH 2 and Cl substituents enhance electron density at N -adsorption sites via conjugative and inductive effects, thereby strengthening the adsorption affinity of 5-aminobenzotriazole (BTA-5NH 2 ) and 5-chlorobenzotriazole (BTA-5Cl). In contrast, the carboxyl group in benzotriazole-5-carboxylic acid (BTA-5COOH) produces the opposite effect. Although substituents themselves participate in interfacial adsorption and contribute to the adsorption energy, their effects appear to be suppressed in an acidic slurry. Consequently, the corrosion inhibition efficiency of BTA-5NH 2 is 96.1%, followed by BTA-5Cl (95.9%), BTA (95.1%), and BTA-5COOH (55.6%), which is in agreement with adsorption affinity at N -adsorption sites. Finally, BTA-5NH 2 yields the lowest surface roughness of 0.439 nm after CMP. This work may provide fundamental insights that help resolve persistent uncertainties in the rational molecular design of azole-based corrosion inhibitors.