Electrochemical effect of Copper Gleam additives during copper electrodeposition

Electrochemical nano and micro fabrication by flow and chemistry is a maskless micro-patterning technology that uses an acid-free and low ion concentration electrolyte. However, the effects of additives on the electrochemical behaviour of this type of electrolyte are still unknown; hence, their role during micro- and nano-fabrication is unpredictable. This study reports the effect of a suppressor (Copper Gleam B), an accelerator (Copper Gleam A) and a promoter (Cl−) on the electrochemical behaviour of copper reduction. The three additives, when employed separately, were found to increase cathode polarisation. The combination of Copper Gleam B and Cl− showed strong inhibition, particularly in the diffusion-limited region. The addition of Copper Gleam A to the Copper Gleam B–Cl− mix increased the limiting current and suggested plating acceleration. These effects are interpreted in terms of the adsorption–desorption behaviour of the additives on the cathode surface.