Published online by Cambridge University Press: 26 February 2011
The mechanical properties of thermally-aged and electric current-stressed eutectic lead (Sn-37Pb) and lead-free (Sn-3.5Ag) solder joints with electroless Ni-P metallization were investigated using tensile testing. Multi-layered test samples, electroless Ni-P/solder/electroless Ni-P, having two electroless Ni-P/solder interfaces were prepared. Tensile testing results showed that for both types of solder, high density electric current causes the brittle failure of solder joint. The eutectic lead solder joint was found to be more prone to current induced brittle failure compared to the lead-free solder joint. In the eutectic lead solder joint, brittle failure always occurred at the cathode side electroless Ni-P/Sn-37Pb interface (where electrons flowed from Ni-P to solder), whereas no such polarity effect was observed in the case of lead-free solder joint.