Key Research Areas

Embedding PCB Technologies for Power Electronics

Inside view (model)of a 90A embedded power module (HHK project)
© Fraunhofer IZM | Volker Mai
Inside view (model)of a 90A embedded power module (HHK project)

Miniaturization and packaging of power electronics by embedding of semiconductor switches into the build-up layers of a printed circuit board has experienced a considerable development throughout recent years. Besides commercialization and the introduction of the first products into the market, there are still a number of interesting new concepts under scientific and technological investigation.

Modular power electronics is a strategy to integrate the heterogeneous components of a more complex power system into one compact and robust module. Such modules consist – in addition to the power switches – typically of gate drivers, controllers and logic elements for measurement and control. Finally, coolers for effective heat distribution are another essential part of such a system. The requirements with respect to thermal, voltage, and current load that each system component has to withstand are, however, quite different. Therefore, each type of sub-module can be realized by an individual technologically and economically optimized embedding approach. Since embedded modules are inherently flat, with copper contacts on the top and bottom of the package, they are ideally suited for area covering or stacked mounting onto a base module followed by subsequent lamination and typical printed circuit board processing.

The core process of system integration into the frame of modular power electronics is a combined process of low-pressure sintering base on silver nanoparticles and lamination of printed circuit board build-up layers with high thermal conductivity. Sintering is used to realize a thermally and electrically highly conductive interconnect between the embedded modules, while the laminated epoxy-based build-up warrants a mechanically robust and insulating interface that encapsulates the electrical interconnects tightly.

Modular power electronics is compact and efficient to manufacture. Moreover, such modules can easily be combined and rearranged for different use cases. For example, the power rating of a module can be scaled up by simply increasing the number of parallel switches and drivers in order to comply with application conditions.