Functionalised copper nanoparticles as catalysts for electroless plating

Abstract

Electroless copper plating of insulating substrates, such as printed circuit boards, typically requires the pre-deposition of a catalyst layer onto the surface to initiate the chemical reactions. Pd/Sn based catalysts are widely used, but carry a high cost and in many cases require specialist pre-treatment of the substrate to achieve good adhesion. In this work, functionalised copper nanoparticles have been investigated as alternative catalysts for electroless deposition. Commercially available copper nanoparticles were functionalised with different organic molecules and their functionalisation was confirmed with X-ray photoelectron spectroscopy. The ability of these particles to act as a catalyst was demonstrated, however their effectiveness was found to depend on the nature of the organic molecules that were used in the functionalisation. Furthermore, significant variability was found between batches of samples in both the particle dispersion and attachment to the substrate surface, which affected the reproducibility of the coverage and adhesion of the subsequent electroless plating, for which further work is required to understand these effects.