Patent ID: 6592737
Filing Date: 2003-07-15
Classification: G01N

Abstract:
An apparatus for determining the concentration of additives in a metal plating bath, comprising:a reference electrode, housed in an electrically isolated reference chamber and immersed in a base metal plating solution; a test electrode having a plating surface upon which metal is depositable by electroplating, disposed in a measurement chamber containing an electroplating current source electrode, wherein metal plating solutions containing known and unknown concentrations of additives are introduced to, and intermixed with, the base metal plating solution to form a mixed metal plating solution; a capillary tube joining the reference chamber and the measurement chamber in unidirectional fluid flow relationship, having a reference chamber end disposed in the reference chamber and a measurement chamber end disposed in the measurement chamber, whereby base metal plating solution is transferred to the measurement chamber from the reference chamber, and wherein the measurement chamber end of the capillary tube is disposed in close spatial relationship to the plating surface of the test electrode; selectively controllable electroplate driving electronics electrically and operatively coupled between the test electrode and the electroplating current source electrode, for selectively effectuating deposition of metals onto the test electrode from the mixed metal plating solution in the measurement chamber, wherein said electroplate driving electronics have two selectable modes, the first mode for providing an initial high plating current density for a short duration, and the second mode for providing subsequent constant or known current density for a duration sufficient to measure electrical potential; and electrical potential measuring circuitry electrically and operatively coupled between the test electrode and the reference electrode, whereby electrical potential between the test electrode and the reference electrode is measured and recorded.