Relevance of the potentiodynamic method in parameter selection for pulse-plating of Co-Cu/Cu multilayers

Results of potentiodynamic measurements and current transients recorded during pulse-plating of Co-Cu/Cu multilayers were compared. Three electrolytes prepared with different components (metal sulfates; metal sulfates and sodium citrate; metal sulfates and chlorides plus boric acid) were used. It was observed for each electrolyte used that the onset potential of Co dissolution as observed on the potentiodynamic curves depends on several experimental parameters such as sweep rate, cathodic limit, ion concentrations, pH and also on the number of cycles recorded. It was revealed that the potential at which Cu can be deposited after the deposition of the Co-rich layer without the dissolution of Co can be established only by the measurements of current transients during the potentiostatic Cu deposition pulse. The loss of Co as a function of the Cu deposition potential are given for several sets of deposition parameters. The relevance of the potentiodynamic result for avoiding Co dissolution during pulse-plating of multilayers is also discussed. (C) 2003 Elsevier Ltd. All rights reserved.