Effect of Pd thickness on wettability and interfacial reaction of Sn-1.0Ag-Ce solders on ENEPIG surface finish
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The wetting balance test was used to study the wettability of Sn-1.0Ag-Ce (Ce content = 0, 0.1, 0.3, and 0.5 wt%) solder alloys on electroless nickel/electroless palladium/immersion gold (ENEPIG) surface finishes with Pd thicknesses of 0, 0.05, 0.1, and 0.15 μm. Scanning electron microscopy was used to evaluate the interfacial reaction between the molten solders and surface finish materials during the wetting test. The Ni3Sn4 intermetallic compound (IMC) plays an important role in promoting wetting properties. The Pd layer retards formation of the Ni3Sn4 IMC and changes its morphology, thereby affecting the wettability of the surface finish/solder systems. ENEPIG surface finishes seem to be suitable for use with cerium-containing solders.
KeywordsInterfacial Reaction Surface Finish Solder Alloy Molten Solder Ag3Sn Phase
This research was supported by World Class University program funded by the Ministry of Education, Science and Technology through the National Research Foundation of Korea (Grant No. R32-10124).