Effect of finite element modeling techniques on solder joint fatigue life prediction of flip-chip BGA packages

Solder joint fatigue life in thermal cycling has been studied for decades using the finite element method. A great variety of modeling methodologies such as global/local modeling (sub-modeling) and sub-structure modeling (superelement) has been developed. Many different types of constitutive equations for solder alloys, various loading assumptions, and several definitions of damage parameters have been used. However, the accuracy of these different modeling approaches has not been completely evaluated in literature. There has been some long-standing confusion regarding the modeling assumptions and their effect on the accuracy of models, such as the initial stress-free temperature setting, selection of damage parameters, and choice of element type. This paper presents a comprehensive study of finite element modeling techniques for solder joint fatigue life prediction. Several guidelines are recommended to obtain consistent and accurate finite element results.