Method for measuring concentrations of metal ion in electrodeposition solutions

A method for measuring a concentration (Cu) of a metal ion in an electrodeposition solution comprising the steps of:

• providing a supporting electrolyte solution, wherein the supporting electrolyte solution is acidic and has a concentration of chloride ion less than 0.05 ppm;
• providing a slope (Sc) of a first linear relationship characterizing electrodeposition rates at different concentrations of the metal ion in a calibration mixture;
• providing a plurality of samples of a test mixture, wherein each sample of the test mixture is prepared by contacting a supporting volume (Vo) of the supporting electrolyte solution with a respective addition volume of the electrodeposition solution, and the respective addition volumes of the electrodeposition solution used in preparing the plurality of samples of the test mixture are different;
• measuring an electrodeposition rate for each sample of the test mixture using a voltammetric measurement method;
• calculating a slope (Ss) of a second linear relationship characterizing electrodeposition rates at different addition volumes of the electrodeposition solution in the test mixture based on the measured electrodeposition rates of the plurality of samples of the test mixture and the respective addition volumes of the electrodeposition solution;
• and
• calculating the concentration of the metal ion in the electrodeposition solution by the following equation:
• c
• u
• =
• s
• s
• s
• c
• ·
• V
• 0
• .