Low-temperature creep of SnPb and SnAgCu solder alloys and reliability prediction in electronic packaging modules

Creep tests covering a broad temperature range (−40 to 120 °C) were systematically performed on Pb5Sn and Sn3Ag0.5Cu solder alloys. Experimental results showed that both solder alloys creep significantly within the temperatures and stress levels tested. A single set of constitutive equations was constructed to describe creep deformation over a wide range of stress and temperature. Numerical analyses revealed that, when evaluating creep failure, significant errors may result from ignoring creep at low temperatures, especially for the lead-free solder alloy Sn3Ag0.5Cu.