Reliability assessment of PCB for smart secure applications

This paper aims to report on employing Finite element (FE) models to evaluate influences of thermo-mechanical stresses and strains by means of numerical simulations of PCB behavior in presence of both, embedded active and passive components as well as large surface mounted components. Simulation runs permit to locate and monitor mechanical stress concentration and accumulating plastic and creep strains over the process steps and through several thermal cycles. Thermo-mechanical reliability investigations addressed mechanical stress concentrations as well as accumulating equivalent creep strains, the latter serving as failure criterion for low cycle solder fatigue. Significant strains and stresses are monitored to evolve in the dies and interconnects of the embedded elements, primarily induced by the coefficients of thermal expansions (CTE) mismatch between PCB and components.