Virtual prototyping of PoP interconnections regarding electrically activated mechanisms

Abstract

The technology is standing evolving. As a consequence, the stress the electronic components are submitted to are aggravated; at package and assembly levels, one has to face the densification of internal interconnections (SiP), the juxtaposition of RF, analogue, digital and power blocks and the processes are more aggressive do to the 3rd dimension like in PoP for instance. Reliability issues increase, as for instance thermal gradients or current densities are higher. So the reliability has to be taken into account at the design phase, and virtual prototyping is a good way. In this work reliability tests on bump chains and finite element simulations with 3-dimensional PoP models were carried out. Very good agreement was found between simulations and calculations of the mass flux divergence values due to electromigration and measurements und thermal loads concerning the failure sites. The maximum current crowding and electromigration mass flux was found in the via-in-pad of the bottom bumps.