Abstract
Ag/Pd nanoparticles stabilized by poly(vinylpyrrolidone) (PVP) have been synthesized successfully in various molar ratios. The PVP-stabilized Pd and Ag/Pd nanoparticles were found to hold strong potential to replace conventional activator Pd/Sn colloid for electroless copper deposition. The essential property of Pd-PVP and Ag/Pd-PVP nanoparticles will be discussed, including the TEM images for the particle sizes, the ex-situ UV-vis spectra analysis. XPS data and mixed potential for the growth mechanism of Ag/Pd nanoparticles. The catalytic activity will be measured by QCM and CV. The application of Pd-PVP and Ag/Pd-PVP nanoparticle is used as the activators in the PTH (plating-through-hole) process. Using Pd-PVP and Ag/Pd-PVP as activators led to poor back-light performance if SPS process in included as in the conventional practice. Adding phosphoric acid to adjust pH of the activator would improve back-light performance with SPS process for both Pd-PVP and Ag/Pd-PVP. However, the stability of Pd-PVP and Ag/Pd-PVP nanoparticles was found to be sensitive. Accordingly, in order to extend the lifetime of activators, adding appropriate additive is necessary. The back-light performance and the thermal stress test showed that using Ag/Pd-PVP as activators is qualified for replacing the Sn/Pd colloid. Since Ag/Pd-PVP is less subject to oxidize by aerating, and the material cost will reduce by partially replacing palladium by silver, so Ag/Pd-PVP has the potential to become a commercially competitive product.