Electrochemical study of multi-component additive behavior during copper electrodeposition with a microfluidic device and an electrochemical quartz crystal microbalance

The adsorption behavior of multi-component additives during Cu electrodeposition was investigated to examine the role of single species in the early period of Cu electrodeposition. First, the current density (i) transition curves were measured using a microfluidic device for rapid exchange from the base electrolyte to electrolytes with bis(3-sulfopropyl)-disulfide (SPS), Janus Green B (JGB), and polyethylene glycol (PEG) to determine the effective surface coverage ratio (theta(EFF)) of the electrodes by PEG, which is the first result with the multi-component system using a microfluidic device. The desorption behavior of additives was also investigated, and the presence or absence of PEG was found to be a key factor in maintaining the additives' effects. Finally, the increase in the weight on the electrode (Delta m) by the additives was measured using a flow cell-type electrochemical quartz crystal microbalance (EQCM) to calculate theta(EFF) by Delta m, which revealed that the suppression of i was roughly dominated by the adsorbed PEG amount, even in a multi-component system. (C) 2015 The Japan Society of Applied Physics