Thermal characteristics and investigations of a novel power module technology using organic insulators

摘要

Power semiconductors are built up in discrete devices or in so called power modules. These power modules are consisting of different arrangements of conductor and insulator materials. In order to discuss how different thermal stacks perform, it is necessary to analyse the fundamental differences between junction to case and junction to ambient thermal resistances and impedances. A specific thermal stack may have a very low junction to case thermal resistance, but thermally perform very poorly because of the high junction to ambient thermal resistance. Accordingly, the following investigation works with different simulation models which include different thermal stacks and different cooling technologies. An advanced module setup using organic insulation foils and Cu lead frames will be compared to a standard power module setup with DBC, with and without a copper baseplate. The thermal investigations include steady state and transient simulations. The simulation results show that power modules with organic insulators have a big difference between junction to case and junction to ambient thermal resistances compared to the standard ceramic based modules. It is shown that the optimum power module solution depends on the load profile. Finally, a real power module design is analysed with the help of the investigation results.