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.