Significant improvement of the thermal stability and electrochemical corrosion resistance of the Au/Pd surface finish through catalytic modification.

Graphical abstract Highlights • Comparative study between Au/Pd (EPIG) and Au/Pd/Au (IGEPIG) surface finishes. • Modification of Pd (EP) via replacement of Pd catalysts by a Au nanolayer. • Pd (EP) of IGEPIG possessed larger grains with limited nanovoids and nanochannels. • A dense Pd film significantly enhanced the thermal reliability and corrosion resistance of Cu. • IGEPIG surface finish has better thermal/corrosion properties than EPIG. Abstract The thermal reliability and electrochemical corrosion of Au/Pd (electroless palladium/immersion gold, EPIG) and Au/Pd/Au (immersion gold/electroless palladium/immersion gold, IGEPIG) surface finishes over Cu traces were characterized in this study. The predeposition of a Au nanolayer over Cu (i.e., IGEPIG case) served as the catalysts for the electroless reduction of Pd2+ ions and modified the polycrystalline Pd structure (EP) into a dense Pd film with limited grain boundaries and nanochannels/nanovoids. This phenomenon greatly improved the thermal reliability and corrosion resistance of the Au/Pd/Cu structure (EPIG case), even though the predeposited Au film was only 10 nm thick. [ABSTRACT FROM AUTHOR]