Highly reliable power modules by pressureless sintering

In this work a novel highly robust pressureless sintered top side leadframe technology for extensive chip sizes over 1 cm² will be presented. Power cycling tests demonstrate superior power cycling capability compared to conventional wire bonded as well as pressure assisted sintered top side contacts. The assembly process steps will be explained and differences of both sinter technologies will be pointed out. The applied leadframe shows special perforation patterns, enabling the required oxidation of pressureless silver sintering pastes. FEM simulations were executed for investigating the influence of different perforations of the leadframe on the thermo-mechanical stress on the top side sinter layer. Furthermore the results of the power cycling tests and the failure mechanism of two differ ent leadframe designs in combination with both silver sintering technologies are shown.