An electrochemical approach to total organic carbon control in printed circuit board copper sulfate plating baths Part I: Anode performances

An electrochemical approach to decreasing high levels of total organic carbon (TOC) in printed circuit board (PCB) copper sulfate plating baths has been investigated. The organic contaminants build-up over the course of pattern plating of PCBs, and at high concentrations they interfere with the quality of the plated copper. The electrochemical approach involves destroying the organic contaminants using electrochemical oxidation. Various anode materials (glassy carbon, lead, lead dioxide, platinum, iridium dioxide and doped tin dioxide) were screened for this application. Some corrosion data is presented for these anodes and their performance for TOC removal at various current densities has been roughly quantified using an apparent first order rate constant. The three best performing anode materials gave increasing oxidation rates going from platinum to doped tin dioxide to lead dioxide, unfortunately anode stability decreased in the same order.