Synthesis of hydrophilic and hydrophobic Pd nanoparticles with in situ generated reducing agent and their application as activator for electroless copper and nickel depositions

A novel method to selectively prepare hydrophilic (hy-Pd-nm) or hydrophobic Pd (hp-Pd-nm) nanoclusters simply by regulating reflux time has been developed. By this method, uniform Pd nanoclusters, well-dispersed in aqueous or organic solvents, can be obtained. Both hy-Pd-nm and hp-Pd-nm can be used successfully as activators for electroless metal deposition. The surface modifications of the hydrophilic and hydrophobic Pd nanoparticles both display a short induction period for catalyzing electroless nickel (EN) bath due to protection- agent inhibited adsorption of the reducing agent of a neutral EN bath. In an alkaline electroless copper (EC) bath, hy-Pd-nm easily catalyzes in the bath and has a faster deposition rate compared with hp-Pd-nm because the surfactant, sodium dodecyl sulfate (SDS), could be repulsive and desorbed by OH-. Finally, the electroless copper deposition rate was found to increase if SDS concentration was decreased. (c) 2005 The Electrochemical Society. [DOI: 10.1149/1.1937977] All rights reserved.