Delamination risk evaluation for plastic packages based on mixed mode fracture mechanics approaches

The growing application of advanced electronic packages under harsh environmental conditions, extreme temperatures especially in automotive applications is often a reason for damage, fatigue, and failure of entire components and systems. Consequently, their thermo-mechanical reliability is one of the most important preconditions for adopting these technologies in industrial applications. To prevent chips from being exposed to the external environment integrated circuits are usually encapsulated into packages. As a result, a microelectronic package is basically a compound of several materials with quite different Young's moduli and thermal expansion coefficients. Additionally, various kinds of inhomogeneity, residual stresses from several steps of the manufacturing Process contribute to interface delaminations, chip cracking, and fatigue of solder interconnects. This paper intends to investigate mixed mode interface delamination phenomena in micro components by using combined numerical investigations by means of nonlinear FEA and experimental investigations. It explains how experimental data were used as input for the quantitative evaluation of fatigue and fracture of microcomponents. Both numerical and experimental investigations provide the basis for understanding and evaluating failure mechanisms especially in solder joints, as well as several polymer material interfaces, and should support further applications for raising the thermo-mechanical reliability of advanced electronic packages.