Study of Suitable Palladium and Gold Thickness in ENEPIG Deposits for Lead Free Soldering and Gold Wire Bonding

摘要

A study was conducted to determine the reliability of lead free solder joints and wire bonds when ENEPIG is used as the surface finish. Different palladium and gold thicknesses were evaluated and their subsequent effects on the composition of the inter-metallic compound (IMC) and the wire bond strength were determined. Optimum thicknesess for lead free soldering and wire bonding were identified. A thickness range were both activities can be completed with high reliability was determined. The IMC was studied for both Sn-3.5Ag and for Sn-3.0Ag-0.5Cu (SAC305) solder alloys, in an attempt to explain the difference in solder joint reliability between the two lead free solders.