Improvement of Power Module System Solders by Directional Solidification

Conference: CIPS 2018 - 10th International Conference on Integrated Power Electronics Systems
03/20/2018 - 03/22/2018 at Stuttgart, Deutschland

Proceedings: ETG-Fb. 156: CIPS 2018

Pages: 5Language: englishTyp: PDF

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Hutzler, Aaron; Oetzel, Christoph; Friker, Emil (PINK GmbH Thermosysteme, Wertheim, Germany)

To improve the quality of large area solders in terms of void-rate and reliability, a novel directional solidification mechanism (DSM) for the soldering process was developed at PINK GmbH Thermosysteme. This mechanism controls the heat flow during cooling and thereby significantly reduces shrinkage-voids in system solder layers. In this study thermal simulations were performed to customize the mechanism to the test-vehicles. Afterwards, temperature measurements and soldering tests were performed to verify the simulations and the directional solidification mechanism. Lastly, the samples were analysed by x-ray and cross sectioning. To show the effect of DSM two groups of samples were assembled. Group A was cooled down with DSM and group B with a standard cooling plate. For this comparison, DBC-substrates were soldered to Cu-baseplates with a SAC305 solder. With DSM, the void-rate was 26 % and the standard deviation 50 % lower due to the reduction of shrinkage-voids.