Double-sided cooling lowers semiconductor costs

May 27, 2011 // By Christoph Hammerschmidt
If power modules can be cooled more effectively, the semiconductors in these modules could be utilized beyond the usual thermal limits. This could lead to cost reductions and / or lifespan improvements for the semiconductors. Fraunhofer Institute for Reliability and Micro Integration (IZM) has developed such a module - IGBTs and diodes inside are water-cooled from both sides.

According to the institute, the cooling technique implemented in the module could permit the usage of lower-cost semiconductors in particular in power train applications for electric vehicles. In addition, the cooling system could have beneficial effects to the circuit board and the components used. The challenge lies in the thermo-mechanical resilience of the mechanical design as well as in the methods to achieve the lowest thermal resistance possible. In addition, the assembly requires significant production expertise, the researchers say. The design also represents significant accurateness with regard to electric strength, power lead implementation and leak tightness.

The demonstrator includes a bridge section with four IGBTs and four diodes which are soldered to both sides of a direct copper bond (DCB). Since additional heat can be dissipated at the top side, thermal resistance could have been reduced by 30 percent compared to single-sided cooling systems, the researchers say.