Enhancement of electroless copper coatings by triazole dithiocarbamate and green additives

This work explores the deposition of nanoscale copper utilizing five different electroless bath formulations based on xylitol. Good complexation, reduction, and pH control were demonstrated in the first bath using xylitol, glyoxylic acid, and potassium hydroxide. A modified version included 1,2,4-triazole (Tz), which served as a stabilizing agent and a strong inhibitor. To enhance environmental compatibility and regulate deposition behavior, later formulations included chitosan (CS), triazole dithiocarbamate (TzDTC), and methanesulfonic acid (MSA) at a concentration of one part per million. Copper deposition was effectively accomplished at pH 12.75 and 45 °C. The optimized additive combination improved corrosion resistance, as evidenced by a drop in icorr from 58.3 to 41.8 mA/cm², reduced surface roughness from 155.8 nm (plain bath) to 19.0 nm (brightener bath), and reduced the amount of deposit from 3.46 per hour to 2.68 µm/h. The specific surface area increased in conjunction with the crystallite size falling from 24.07 to 20.17 nm. TzDTC significantly changed the electrochemical and physical characteristics of the bath. In contrast, CS improved the smoothness and homogeneity of the copper layer that was deposited by acting as a brightener and leveling agent. The article describes the resulting shiny copper coatings and methodically assesses the additives' inhibitory and accelerating effects. Surface texture was assessed using XRD and atomic force microscopy (AFM), and corrosion behavior was evaluated using cyclic voltammetry and Tafel polarization.