ELECTROPLATING BATH ANALYSIS

A method based on electrochemical impedance spectroscopy (EIS) is used to determine the amount of one or more organic additive in a metal electroplating bath. The method comprises the steps of: a) providing an apparatus having a rotatable working electrode, a counter electrode, a reference electrode, a potentiostat, and a frequency response analyzer, wherein the counter electrode is in operable communication with the working and reference electrodes; b) obtaining a metal electroplating bath solution comprising an unknown quantity of organic additive; c) contacting each of the working electrode, reference electrode and counter electrode with the metal electroplating solution, and cleaning the working electrode surface by applying a positive potential while rotating the working electrode at a first rotation speed; d) equilibrating convection in the electroplating solution by rotating the working electrode at a second rotation speed at open circuit potential; e) applying a potential to the working electrode that is 50 to 500 mV negative of the metal underpotential deposition peak and overlaying an alternating potential perturbation of from 1 to 100 mV; f) measuring an impedance response of the organic additive solution over a frequency range of from 10 kHz to 1 mHz; g) selecting a frequency from the impedance response; and h) determining a concentration of the organic additive by comparing the impedance response at the selected frequency to a calibration curve.