Study of the adsorptive behavior of Pd/PVP nanoparticles and its interaction with conditioner in electroless copper deposition

Sn/Pd colloid has been used as activator for plated-through-hole (PTH) manufacturing of printed circuit boards (PCB) for more than 30 years. However, the ever stringent demands from PCB and IC industries promote the development of new activators to replace the traditional but still very useful Sn/Pd colloid. In our study, we have developed a new substitute in the form of Pd nanoparticles protected with PVP (Pd/PVP). We measured the Pd adsorption, Cu deposition and activity on plane substrates. Then we studied the copper morphology inside holes. The adsorptive and protective mechanism of Pd/PVP was also studied. The bonding between Pd/PVP nanoparticles and PCB was found to be Van Der Waal Force rather than the electrostatic force in the case of Pd/Sn colloid. The result indicates that Pd/PVP has achieved industrial acceptable activity and has the potential to replace Sn/Pd colloid.