Molded Electronic Package Warpage Predictive Modelling Methodologies

Simulation tools such as FEA or CFD are widely employed to predict the thermal mechanical behavior of an electronic package based on the design and material attributes. Prediction accuracy and representation are highly dependent on the material model (visco-elastic, chemical shrinkage etc) and analysis approach especially for mold encapsulated packaging. In this paper, a basic evaluation was conducted using an arbitrary bi-material model to compare the material model of visco-elastic, time-temperature superposition shift factor and chemical shrinkage based on PVTC in both Moldex3D and FEA-A tools. The impact of visco-elastic constitutive property with temperature effects were included with a two steps shift factor model of Arrhenius and WLF functions. The implementation equations and analytical solutions are presented together with a detail discussion of the property model used. Transient heat transfer and structural analysis steps were incorporated to simulate the impact of visco-elastic property and shrinkage to the bi-material model.