Investigating the mold compounds influence on power cycling lifetime of discrete power devices

Inhalt:
Recently performed lifetime modelling based on various power cycling tests, including tests with superimposed passive thermal cycles, indicated a strong influence of the mold compound with its characteristic glass transition temperature Tg on the failure mechanism wire-bond lift-off within discrete power device packages. The paper reports the discussion of this influence on the lifetime modelling and details its investigation. It also includes electro-thermo-mechanical finite element simulations as well as the introduction of a new optical in-situ analysis method capable of visualizing the in-plane deformations and strains in the package during power cycling.