3D Power Packaged Device Thermo-Mechanical Modeling and Stress Analysis After Reliability Trials

Power devices technology innovation is moving to new metallization schemes in order to improve electrical performances. The integration of new materials, especially low-k dielectric, requires an increasingly deep understanding of thermo-mechanical stress due to packaging processes and reliability. In this work, a 3D Power Package thermo-mechanical modeling is presented as a powerful tool to predict stress generation not only on fresh die but also after reliability trials. Mechanical properties of two different polymeric materials, available both for as-molded and aged material at different temperatures, are implemented in the model in order to better reproduce strain and deformation at the end of each reliability trial. The above-mentioned package model is then coupled with the silicon chip top surface by the sub-modeling technique to achieve a micro-scale more accurate stress estimate; the focus of stress analysis is on delamination failures mode.