Use of organic reductants to lower brightener consumption in acid copper electroplating bath utilising catalytic anodes

Catalytic anodes are an enabling technology for high speed, horizontal acid copper electroplating. However, their usage is associated with high additive oxidation rates which can be problematic in terms of cost and control of the electrolyte. The addition of certain 'organic reductants' to the electroplating solution has been found to have a dramatic effect on brightener consumption when catalytic anodes are employed. This paper reports an investigation of three such compounds having varying functionality with respect to brightener oxidation. It was found that the ability of a particular organic reductant to influence brightener oxidation was related to its electrochemical properties on a particular anode material. However, it is postulated that the species' mechanism of oxidation and its anti-oxidant properties may also be important factors.