Influence of of mercapto azole additives on the characteristics of autocatalytic copper nano film deposition

This article aims at analysing the influence of structurally related two azole additives such as 2-Mercaptobenzothiazole (2-MBT) and 2-Mercaptobenzimidazole (2-MBI) in the rate of autocatalytic copper nano film depositions. The effect of these stabilizers on the characteristics of both the electroless plating bath and electroless copper deposition
is also studied. Dimethylamine borane (DMAB) is employed as the reducing agent and sorbitol as complexing agent in the copper methanesulphonate bath. Potassium hydroxide acts as the suitable pH regulator to modify the properties of copper nano
deposits. 1 ppm of the azole additives are added in this eco-friendly bath and optimized
at a pH of 12.75 ± 0.25 at a temperature of 28±2 °C. The results obtained from various studies imply that 2-MBT had an inhibiting effect on copper deposition, whereas 2-MBI
accelerated the deposition rate. The physical properties like deposition rate, thickness and activation energy are calculated to support the stabilizing effects of 2-MBT and 2- MBI. Surface morphology of the copper deposits is characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques. Structural
properties such as crystallite size and specific surface area of plain bath and additives laden baths are investigated using X-ray diffraction studies.