Electrochemical spectroscopic analysis of additives in copper plating baths by DRT and multivariate approach

The concentration of additives of a copper electroplating bath with a complex matrix are quantified using electrochemical impedance spectroscopy (EIS). The Experimental data were processed to calculate the distribution of relaxation times (DRT) using Lasso regression and the results were fed to a multivariate analysis to overcome this challenge. The complex nature of electroplating bath matrices, often containing various organic additives, poses challenges for traditional analytical methods. The proposed approach enables the direct measurement of additive behavior within the bath, regardless their chemical composition. This method offers distinct advantages over conventional techniques, such as chromatography, Hull cell test and cyclic voltametric stripping (CVS).