Abstract:

Global transition to Pb-free electronics has led component and equipment manufacturers to transform their SnPb process to Pb-free. At the same time, Pb-free legislation has granted exemptions to industries where alternatives to SnPb are not scientifically feasible or cost-effective. However, compatibility concerns can arise if Pb-free components have to be attached with SnPb solder. This paper discusses the effect of aging on the pull strength of pure SnPb, pure Pb-free and solder joints formed when Pb-free QFP components are attached with SnPb solder paste. Solder joint strength for quad flat pack (QFP) packages have been studied as a function of aging, circuit board pad finishes (Electroless Ni over Immersion Gold (ENIG), Immersion Silver (ImAg) and Immersion Tin (ImSn) and component lead finishes (Sn, Sn0.7Cu, Sn2Bi)

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