Abstract
Electroless deposition of metal onto nonconductors, such as ceramics, glass and plastics, requires a catalyzation pretreatment of substrates. Adsorbates formed on glass or mica substrates by two-step catalyzation (sensitization-activation) have been investigated by quantitative analysis of Sn and Pd on substrates, XPS and AFM. Adsorbates, formed on the substrate by the sensitization, included divalent Sn and O, and no Cl was included. There were two kinds of Sn adsorbates, weak adsorbed ones and strong adsorbed ones. The former was in an equilibrium state to Sn2+ in the sensitizer, therefore, it was desorbed from the substrate by immersion into HCl solution, and was recovered to the same amount by the sensitization after the immersion into HCl solution. Elemental Pd which included no Cl was produced on the substrate by the activation after the sensitization. The amounts of Sn and Pd adsorbates were increased by the repetition of sensitization and activation. The activity of the catalyzed substrate for the electroless deposition was lost by the sensitization. AFM inspection showed that fine particles (10–15nm in size, 0.5–1.0nm in height, 4–5×103 particles μm-2 in density) were formed on the substrate by the sensitization, and the height and density of particles were enlarged by the activation. The process of two-step catalyzation was explained by using a model based on these results.
