NXP Semiconductor at Caen, which has System in Package (SiP) technologies development competences and NXP Semiconductor at Eindhoven, which has virtual qualification specialization jointed to study fast reliability qualification of SiP products. A thesis focused on simulations started at TU Delft University (Netherlands) with Xiaosong Ma directed by Kaspar Jansen and another thesis focused on experimentation started at Bordeaux 1 University with Charles Regard directed by Hélène Frémont. These thesis were lead on close collaboration. In a first time, the tests vehicles were defined by both the PhD students. Then materials characterizations and simulations were performed at TU Delft, and experimental qualification tests and physical analyses were performed in Caen. A long of these thesis, constant exchanges allowed to correlate simulations by experimentation. This industrial need of SiP product qualification study is due to the strong increase of functions integration into mobile equipments. Thus the SiP technology allows to provide in relative short time miniaturized products imposed by the new developments. This thesis work's goal is to get methods and techniques to optimize System in Package (SiP) reliability qualification.