Pure Palladium and Palladium Phosphorus Depositions Used in ENEPIG and ENEP Surface Finishes – Comparison of Physical Properties and Their Influence on Soldering and Au Wire Bonding

Abstract

As a surface finish, electroless nickel / electroless palladium / immersion gold (ENEPIG) has received increased attention for both packaging/IC-substrate and PWB applications. With a lower gold thickness compared to conventional electroless nickel / immersion gold (ENIG) the ENEPIG finish offers the potential for higher reliability, better performance and reduced cost.[1,2] This paper shows the benefits of using a pure palladium layer in ENEPIG and ENEP (Electroless Nickel / Electroless Palladium) surface finishes in terms of physical properties and in terms of gold wire bonding and solder joint integrity.