Mechanisms of power module source metal degradation during electro-thermal aging

R. Ruffilli, Mounira Berkani, Philippe Dupuy, Stéphane Lefebvre, Y. Weber, Marc Legros

Abstract: Highlights•Electron and ionic imaging of aged metallization and wire bonding•Degradation of metallization linked to heavy grain boundary diffusion of aluminium•Mechanical stress due to electro-thermal cycling reaches hundreds of MPa•Failure due to local hot spots able to melt aluminium•Finer cracks in silicon contain aluminium, evidencing a non-immediate shutdown of power device