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Thermal Heat Sink Interface of IGBT Modules w/o Base Plate

The thermal interface between power modules and heat sink is studied in detail by means of a new set-up enabling the simultaneous measurement of thermal resistance and thermal grease thickness. The design of the set-up is studied in detail and various measurements enabled by this new equipment are presented. Among these are the module mounting process and the mechanical behaviour of the grease layer under power cycling conditions. From comparison with simulations the presence of a thermal contact resistance between module or heat sink, respectively, and grease is derived and the thermal interference of neighbouring chips is investigated. We have introduced a newly developed experimental set-up capable of measuring both thermal resistance and thermal grease thickness. The placement of the thermocouple within the heat sink has been shown to be crucial for obtaining accurate results. From a thermal grease thickness series and comparison of experiment and simulation it has been derived that a thermal contact resistance exists which contributes significantly to the case – heat sink thermal interface… Finally, the usefulness of mounting clamps for modules without base plate has been demonstrated and the settling of a module after mounting has been measured in situ.

• 384.03 KB
• 07/02/2014