Controlling the oxidation of organic brightener during electroplating using an ion-exchange membrane

The effect of an ion-exchange membrane combined with a dimensionally stable anode on the oxidation rate of organic brightener and electroplating performance was investigated. The oxidation rate of the brightener was measured by analyzing the total organic carbon content in the plating solution. The oxidation rate increased rapidly as the current density increased when there was no ion-exchange membrane. However, when an ion-exchange membrane was present, the oxidation rate of the brightener was significantly reduced by Neosepta CMX and CMS cation-exchange membranes. The CMS monovalent selective cation-exchange membrane in particular was the most effective in reducing organic brightener oxidation, regardless of the current density. Through-hole printed circuit board electroplating was more precise with an ion-exchange membrane than with no membrane. These results confirmed that the electroplating performance was improved by the presence of an ion-exchange membrane on the anode, effectively inhibiting the oxidation of organic brightener.