Dielectric strength and thermal performance of PCB-embedded power electronics

Advantages of embedded power electronics compared to classical soldered and bonded DCB modules are smaller size, less weight, and cost savings (Hofmann et al., 2012) [1]. In addition, the low parasitic inductance provided by the embedded technology offers the potential to better utilize the maximum chip voltages and the use of fast switching semiconductors. Compared to a standard module of 15.4 nH, the measurement at the embedded module showed 2.8 nH (Neeb et al., 2014) [2]. Heat-spreading in the thick copper plate inside the printed circuit board improves the thermal conductivity. At the same time, by combination with silver sintering for the die attach, higher lifetimes compared with standard DCB (direct copper bonding) assemblies may be reached. Potential risks of this new approach are lifetime limitations, and restricted dielectric strength and thermal performance of the module. In order to evaluate the embedding technology for power devices, test samples were designed and fabricated. In this study, different PCB materials were evaluated. Temperature dependent thermal conductivity of each material was measured and temperature-dependent partial discharge tests have been conducted.