Creep failure mechanism and life prediction of lead-free solder joint

The reliability of solder joints in electronic products has received a lot of concern. The creep behavior is an important property for lead-free solder. In this research, creep tests were conducted to the Sn3.0Ag0.5Cu solder joints. Creep failure mechanism was analyzed and creep life was evaluated based on the Monkman-Grant and Larson-Miller parameter model. The results show that separation is easy to take place at dendrite grain boundaries. Creep cavity initiates at triple junctions of dendrite grains in solder matrix near the intermetallic compound layer. The creep fracture morphology at low temperature and high stress comprises three regions: the shear plane, shear lip and the instantaneous rupture zone. However, the shear plane region is disappeared with increasing the temperature and decreasing the stress. The rupture surface is characterized by the shear lip and inter-granular failure morphology. The Monkman-Grant equation and Larson-Miller parameter model can be used to predict the solder joint creep life.