Reliability evaluation of solder joints in electronics assemblies

This study treats the reliability of solder joints of electronic assemblies, in terms of methodology of evaluation, applicable stress tests and analyses. This study is focused on lead-free solder alloys and describes the solder joint microstructure and its changes caused by thermal stresses, ATC (Accelerated Thermal Cycling) and thermal shock, which cause thermomechanical stresses to the solder joints. In particular, this study compares the different stresses caused by the fast and slow thermal swings. Another topic is a revision of the criteria to evaluate the solder joints on the base of the link between the stress tests and the conditions of the product life. Finally, a proposal for the stress tests and the evaluation criteria is described.