Patent ID: 6709568
Filing Date: 2004-03-23
Classification: G01N

Abstract:
A method for determining concentration of brightener and leveler contained in an aqueous acid metal electroplating solution, comprising the steps of:(a) providing a measuring apparatus that comprises: (i) a reference electrode; (ii) a rotating disc test electrode having a plating surface for depositing metal thereon and a rotational driver for rotating said rotating disc test electrode at a predetermined rotation speed, wherein said rotating disc electrode is disposed in a measurement chamber that comprises an electroplating current source electrode, and wherein the aqueous acid metal electroplating solution is introduced into the measurement chamber for measurement; (iii) electroplating-driving electronics that are electrically and operatively coupled between the rotating disc test electrode and the electroplating current source electrode, whereby metal is selectively deposited onto the plating surface of said rotating disc test electrode from the aqueous acid metal electroplating solution in the measurement chamber at a constant known current density; and (iv) measuring circuitry electrically and operatively coupled between the rotating disc test electrode and the reference electrode for measuring the electrical potential between the rotating disc test electrode and the reference electrode; (b) determining the concentration of brightener in the aqueous acid metal electroplating solution, by using said measuring apparatus to measure a first electrical potential of said metal electroplating solution at a first rotation speed and for a first electroplating duration, and by performing Pulsed Cyclic Galvanostatic Analysis of the first electrical potential measured; and (c) determining the concentration of leveler in the aqueous acid metal electroplating solution, by using said measuring apparatus to measure a second electrical potential of said metal electroplating solution at a second rotation speed and for a second electroplating duration, and by performing Pulsed Cyclic Galvanostatic Analysis of the second electrical potential measured, wherein the first rotation speed is lower than the second rotation speed, and wherein the first electroplating duration is shorter than the second electroplating duration.