Patent ID: 6827839
Filing Date: 2004-12-07
Classification: C25D,G01N

Abstract:
A method for determining the quantity of both brightener and leveler in an electroplating bath having an unknown quantity of brightener and leveler comprising the steps of:a) determining the amount of brightener in the electroplating bath having the unknown quantity of brightener and leveler by a method selected from cyclic voltammetric stripping and cyclic pulse voltammetric stripping; b) obtaining a plurality of plating baths where each bath has a known and different quantity of said brightener and leveler, but where the quantity of each in each bath differs from the quantity in the other baths; c) for each bath, providing a counter electrode, a cleaned working electrode and a reference electrode immersed in said bath, and carrying out a predetermined sequence of steps comprising: 1. cleaning and oxidizing the surface of the working electrode at a fixed potential for a period of time; 2. equilibrating said working electrode to absorb brightener according to a step selected from equilibrating without energy input for a time until the change in energy output with time is minimal and equilibrating for a set time at a fixed potential; 3. plating metal ions on said working electrode with energy input for a time selected from a time sufficient to measure initial plating energy output and, a time sufficient to measure the change in energy output with time; and 4. stripping at a potential and for a period of time sufficient to remove the metal ions plated in step 3; d) for each bath, correlating the quantity of leveler with the energy output value obtained in step 3; e) placing said electrodes in said electroplating bath having the unknown quantity of brightener and leveler and performing said predetermined sequence of steps; f) choosing from said correlations in step d), a particular correlation for a bath containing substantially the amount of brightener determined in step a); and g) choosing from the particular correlation in step f), a quantity of leveler which corresponds to said energy outputs recorded for said electroplating bath having the unknown quantity of brightener and leveler.