Etude de la Fiabilité des convertisseurs d'électronique de puissance intégrés dans un circuit imprimé PCB

The works presented in this thesis aim to develop new technologies for the integration of active components in the PCB core. They are based on the use of a pressed metal foam to ensure the electrical and thermal contacts of the top and bottom sides of the chips. This new technology has the advantage of being cheap and allows reducing the parasitic inductance.Electrical, thermal and mechanical characterization studies have been carried out on this new integration technology. The objective is to identify the thermomechanical properties of the interconnection materials, mainly those of the metal foam. The development of a numerical model has reinforced this study aiming to estimate and localize the thermomechanical stresses in the assembly. Finally, a reliability study has been carried out by performing accelerated aging tests (active and passive thermal cycling). The objective here is to identify the weakness areas and to estimate the lifetime of the proposed assemblies. The obtained results are promising compared to conventional power modules. A new method (on-line) to estimate the junction temperature during active thermal cycling has been developed. It is based on the use of voltage variations ΔVF and forward current ΔIF during the conduction phase. The validation tests revealed promoting results.