Embedded Power Modules – A new approach using Power Core and High Power PCB

Abstract

Power electronics packaging applications has strong demands regarding reliability and cost. The fields of developments reach from low power converter modules, over single or multichip MOSFET or IGBT packages, up to high power applications, like needed e.g. for solar inverters and automotive applications. This paper will give an overview about these applications and a description of each ones demand. The spectrum of conventional power electronics packaging reaches from SMD packages for power chips to large power modules. In most of these packages the power semiconductors are connected by bond wires, resulting in large resistances and parasitic inductance. Additionally bond wires result in a high stray inductance which limits the switching frequency. The embedding of chips using Printed Circuit Board (PCB) technology offers a solution for many of the problems in power packaging. This paper will show today's available power packages and power modules, realized in industrial production as well as in European research projects. All technologies which are used are based on PCB materials and processes. Chips are mounted to Cu foils, lead frames, high power PCBs or even ceramic substrates, embedded by vacuum lamination of laminate sheets and electrically connected by laser drilling and Cu plating. A new approach for embedded power modules will be presented in detail. In this project, different application fields are covered, ranging from 50 W over 500 W to 50kW power modules for different applications like single chip packages, over power control units for pedelec (Pedal Electric Cycle), to inverter modules for automotive applications. This approach will focus on a power core base structure for the embedded semiconductor, which is then connected to a high power PCB. The connection to the embedded die is realized by direct copper connection only. The technology principle will be described in detail. Frist manufactured demonstrators will be presented. The presented new approach for the realization of a power core structure offers new possibilities for the module manufacturing, avoiding soldering or Ag sintering of the power semiconductors and the handling of thick copper substrates during the embedding process.