Finite-element modeling of thermal and thermomechanical behavior for three-dimensional packaging of power electronics modules

The goal of realizing highly efficient and highly reliable energy conversion from source to load in power electronics has driven the exploration of thermal handling of power packaging to the 3rd dimension. Innovative 3-D interconnected power package designs have shown their advantages in higher power density, reduced interconnect resistance, noise and parasitic oscillations, better thermal management, higher level of system integration and lower cost. On the other hand, the complicated design and the fabrication process introduce more reliability concerns. 3-D design of power packaging has not yet been fully understood in its thermomechanical reliability. A detailed study in this respect will help in understanding the key issues of thermal management and thermomechanical reliability. In this work, we present a 3-D finite-element modeling of thermal and thermomechanical performance for a 3-D packaged power module fabricated by a stacked-plate processing technique. Thermal cycles simulating working conditions were applied to the model. Parametric study of interconnection geometry and cooling condition led to better understanding in thermal management, and the results are compared with those of a wire bond module. Thermally induced stresses and fatigue were also analyzed in detail.