Innovative connectivity for power dice in mechatronic packaging of automotive power electronics

The automotive industry is today starving for low consumption and environment friendly vehicles. All OEMs and tier-ones are developing programs about Hybrids or Fuel-Cells vehicles. These new developments are going together with the spread of power electronics implemented within the powertrain systems and within more and more electric driven systems, with medium and high power copabilities. It turns out from all those systems that the demand for power electronics equipments, tailored to automotive environment, tremendously raises the need of improved assembly technologies that can provide high durability under high electrical and thermal constrains, Recently, a new robust assembly technology showing excellent compliance with automotive constrains (performance and cost) has been introduced for packaging power dice with mechatronic capabilities. This power mechatronic package is based onto stamped metal tapes embedded in a plastic frame (i.e. IML packaging technology, IML standing for Insulated Molded Leadframe). This IML technology is young compared to other existing railway or industrial assembly techniques but it has already demonstrated numerous advantages in terms of high current and high temperature capabilities. IML power mechatronic technology hosts numerous innovations that have been driven by new approaches like the one described in this document. This paper will introduce research work performed for improving power dice top connections in a way that device current density can increase keeping junction temperatures at reasonable level and enabling dice double side cooling. It will display the reliability comparison betwenn the state of the art of wire bonding technology and the proposed joining process innovations. A comprehensive analysis of reliability has been made using coupled thermo-electrial and thermo-mechanical simulations. The exposed data of this paper demonstrate the very high potentials of that new technology for automotive power mechatronic modules.