Surface morphology of copper deposits by using azine derivatives on an ecofriendly electroless bath

Abstract

This article reports the effect of azine stabilizers such as pyridine, 2,2'-bipyridine and 1,10-phenanthroline during electroless deposition of copper. In this work, the biodegradable copper methanesulphonate was used instead of the traditionally used copper sulphate and the environmentally safe polyhydroxylic compound xylitol was used as the complexing agent. Commercial para-formaldehyde was used as the reducing agent and potassium hydroxide (KOH) was used to optimize the bath in alkaline medium at pH 13.25. Surface morphologies of the electroless coated copper (Cu) substrates were investigated by atomic force microscopic (AFM) analysis. Crystallite size and specific surface area of copper thin film were observed by x-ray diffraction (XRD). Electrochemical characteristics were studied by cyclic voltammetry (CV) and Tafel polarization. The value of charge transfer resistance and double layer capacitance were determined by impedance techniques. In this xylitol bath, 2,2'-bipyridine was found to act as an enhancer but the results are not very different from the plain xylitol bath. Pyridine acted as a strong inhibitor and 1,10-phenanthroline was a good accelerator. All stabilizers provide high stability to the bath at 28 ± 2°C with 1 ppm addition.