Advanced copper electroplating for application of electronics

Copper electroplating has been of much interest for the interconnection of printed circuit boards (PCBs) and ultra large scale integration (ULSI), wiring so-called damascene process. Therefore, copper filling by electroplating has been actively studied. In this research, via-filling for build-up process of PCBs and the ULSI wiring formation without void and overplate has been examined using an acid cupric sulfate bath containing chloride (Cl), polyethylene glycol, bis (3-sulfopropyl) disulfidedisodium, Janus Green B and thiourea. The void-free filling in the range of 0.18–180 μm width via holes and trenches can be achieved by the selection of these additives. It is confirmed that the elements of these additives are detected only on the upper layer part of copper films by glow discharge optical emission spectroscopy.