Copper electrodeposition onto extended surface area electrodes and the treatment of copper-containing waste streams

The paper reviews work on. copper deposition onto porous, fluidized and spouted bed electrodes and discusses the phenomena that are important in governing electrode behavior. An ongoing investigation into the use of ion exchange and electrodeposition to recover copper and water from semiconductor industry waste streams is described. These waste streams, and the associated fresh water consumption, appear to be a growing problem as the semiconductor industry moves to copper metallization (by electrolytic and electroless deposition). Copper metallization also implies the generation of significant waste streams from copper removal by chemical-mechanical planarization (CMP). The quantity of copper to be recovered is still small but its removal from the waste stream will facilitate disposal and, perhaps, reuse of the large volume of water entailed. Extended surface area electrodes may play a role in this task and results using porous carbon electrodes are presented. Recent results on the growth of copper particles in spouted electrodes and the deposition of copper from electrolytes containing other metal salts are presented.