Package Level Warpage Simulation of a Fan Out System in Board Module

摘要

In manufacturing of electronic packages, especially modules manufactured in a panel level based packaging process, the occurring package warpage is always one of the most critical issues. The deformation of manufactured packages is generally triggered by dimensional changes in the material layers due to thermal expansion and chemical shrinkage during the curing process. Being able to predict the occurring warpage can significantly improve design quality and reliability of electronic systems. The current study deals with the application of finite element simulation to predict the warpage after manufacturing and singularization of a fine line structured multi-die package manufactured in a panel level packaging process. For defining the material properties of the applied dielectric materials, temperature dependent linear elastic models were applied considering the temperature dependency of the materials as well as their orthotropy were applicable. For b-staged resins, a coefficient of chemical shrinkage was determined and implemented in the material model. Copper properties were modelled considering temperature dependency and plasticity while directional effects in copper were neglected. All applied material models have been determined in the course of the project. The package structure was modelled in ABAQUS ?, one of the industry standard multi-physics simulation packages, applying a homogenization approach resulting in a rather small but still accurate model of the package. The boundary conditions were specified based on the actual manufacturing conditions in the production line of the package. Finally the calculated, resulting deformation of the package was compared to the actually measured deformation of the packages, where cross-sectioning profilometry, Shadow Moire methodology and X-ray tomography and have been applied to create the validation data. Based on the presented results it could be shown that the applied finite element simulation approach is suitable for describing the warpage occurring during panel level packaging of electronic modules.