| The purpose of this thesis is to develop a model to estimate the fatigue life of Ball Grid Array (BGA) solder joints subjected to cyclic mechanical bending loads using computer simulation. It reviews the various failure modes in BGA, their causes, and regions susceptible to failure. Fundamental aspects of elastic-plastic stress analysis relevant to mechanical fatigue are reviewed for application in the model. In addition, the available fatigue models used in the reliability analysis of BGA are also studied.; Research on these aspects revealed that the strain energy density based approach is the most effective one to study the mechanical reliability of BGA. The strain energy density based approach is integrated with computer simulation and a generalized model for the estimation of fatigue life of BGA solder bumps subjected to cyclic mechanical loads has been developed. |
