Authored By:
H. Stahr, M. Morianz, I. Salkovic
AT&S AG, Leoben, Austria
Summary
Embedded components technology has launched its implementation in volume products demanding high levels of miniaturization. Small modules with embedded dies and passive components on the top side are mounted in hand held devices. Smartphones have been the enablers for this new technology using the capabilities of embedded components. With this technological background another business field became interesting for embedded components – the embedded power electronics. The roadmap of the automotive industry shows a clear demand for miniaturized power electronic applications. Drivers are the regulations for the international fleet emissions which are focusing on three major trends.
The first trend will be higher efficiency of “classic” internal combustion engines, the second will be the efficiency of body application and the last trend will be the electrification of the drive train. For all targets a huge potential for embedded power electronics is visible. A European project was launched in 2013 as a development project for new power packages and power modules using die embedding technology. For the realization of this technology, copper termination on MOSFETs, IGBTs and power diodes is necessary. Equipment and processes have been developed in the supply chain to support the development of power modules ranging from 500 W to 50 kW. For enhanced thermal performance of power modules, a concept for double sided cooling has been developed. Beside full area contacting the MOSFET on the drain side with copper and contacting the embedded components in a power core with an isolated metal substrate with silver sinter paste, a very effective concept for reducing thermal resistances and stray inductance was shown. With the realization of the 500W demonstrator the proof of concept was realized. This paper will focus on the behavior of the power module for operational conditions of a PedEleC (Pedal Electric Cycle) application. The full reliability evaluation (thermal shock test, reflow test and power cycling) and switching behavior was shown. Furthermore, the thermal properties of the PedEleC power module were verified with the results from thermal simulation. In addition, more detailed investigation of the electrical properties before and after reliability treatment of a single chip test vehicle was shown.
Conclusions
During the project a new embedding concept was developed for integration of power components. The embedding technology shows promising potential for automotive applications due to the high miniaturization potential and good electrical performance. Additionally, the concept provides good reflow stability and high resistance against thermal shock testing. The electrical benchmark of the embedded die with a molded package showed equal performance. Especially for the leakage current measurements the embedded version showed superior behavior.
The embedding technology provides the opportunity to deal with automotive customer requirements with a cost competitive PCB technology and comparable or even better electrical, thermal and reliability characteristics.
Initially Published in the SMTA Proceedings
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