Copper Migration Induces Discoloration on a NiPdAu Surface

Pre-plated NiPdAu surface finish is one of the most common terminal finishing in the semiconductor and electronics industries. The plated surface, usually on top of a copper base material, prevents corrosion and promotes solderability for component attach. Herein, we report the analysis of a discolored NiPdAu surface via scanning electron microscopy – energy dispersive spectroscopy (SEM-EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS). The surface determinants found in these series of surface analyses indicate the presence of copper, migrating from the unplated pillars of the leads.