Simultaneous Filling of Microvias and Through Holes by Copper Electroplating for High Density Interconnection of PCB

The development of high density interconnects (HDI) for IC packaging substrate and printed circuit board (PCB) will be a key technology for fabrication of consumer electronic products in the next generation. To meet these demands and requirements of state-of-the-art microelectronic products, both microvias and through holes (THs) will need to be completely metallized; preferably in a void-free manner. Unfortunately current copper electroplating technology that is used for filling microvias cannot provide void-free filling of through holes. In this work, a novel copper electroplating formula is developed that achieves through hole filling while employing DC plating. In addition, this new plating formula simultaneously achieves the filling of microvias and through hole in a single step, thereby simplifying the overall fabrication process