Finite element modeling and simulation of solder interconnection system

This final year project is consisted of three studies to facilitate the author to assess solder joint reliability in different electronic packages using finite element methods In the first study, the impact of different constitutive material on PBGA thermal reliability is investigated. One eight of PBGA model is modeled using Elastic Plastic Creep (EPC) and Viscoplastic Anand’s models. Thermal cycling simulation is carried out for these models and the accuracies of the fatigue life prediction are correlated to experimental data. The appropriate interface for carrying out volume averaging is also investigated. Submodeling method is employed in the first project to reduce number of elements involved in simulation hence leading to shorter simulation time. In the second study, the impact of different constitutive model on a new flip chip interconnect technology is investigated. The thermal reliability of copper pillar-to-solder joint is assessed using Viscoplastic Anand’s model and then compared with Elastic Plastic Creep model. Parametric studies are conducted through the use of ANSYS Parametric Design Language to investigate the effect of geometry on the fatigue performance on the flip chip interconnect. In the third study, the flip chip package is developed based on the proposed pin-head copper pillar-to-solder joint structure. However, there are differences between the complete shape of flip chip package and the proposed copper-pillar structure due to manufacturing related difficulties. There are few major differences in new copper pillar-to-solder joint design. Firstly, Non-Solder Mask Defined (NSMD) is employed in the flip chip package. Secondly, the pin head of copper pillar structure is semi-elliptical in shape. Therefore, the thermal reliability of the semi-elliptical pin head copper pillar-to- solder joint has to be investigated to determine whether it will meet the thermal cycling test requirements.Bachelor of Engineering (Mechanical Engineering