Examination of insoluble anodes used for acid copper plating

Abstract

Until a few years ago, staring with mobile phones and digital cameras, a large volume of substrates for highly functional electronic devices had been manufactured in Japan. Today, represented by Smart-phones and Tablet PC's, highly functional electronic devices continue to evolve, although manufacture has shifted overseas. In overseas manufacture, from the perspective of factory labor technical ability, plating stability, and in-plane uniformity among other factors, insoluble anode copper sulfate plating prevails. However, a known demerit of insoluble anodes, as opposed to soluble anodes, is the larger consumption of additives. This may be inherent to the electrode material, for which we investigated and report here. As a result of the comparison of immersed potential of each material with the additive consumption, we found that consumption increased as the immersion potential of the electrode material increased. This suggests additive consumption significantly occurs at the anode. Meanwhile, no correlation between dissolved oxygen concentration and additive consumption was observed, despite oxygen concentration differences during plating for each anode.