Influence of thermal interface material using discrete Si-IGBTs and consideration of power cycling conditions

Abstract

In this work, the influence of different thermal interface materials (TIMs) on junction temperature and power cycling capability of discrete Si IGBT in TO-247 package is investigated. A difference in the total thermal resistance (junction - heat sink) up to a factor of ten when using different heat conductive foils or paste is to be expected. A temperature deviation between the maximum junction temperature of up to 50 K is possible under the same conditions (i.e. equal, load current, Tvjmin, ton, VGE) during the power cycling test. If the current is increased to achieve the same Tvjmax, the power cycling capability is reduced. This influence and also the electrical insulating capacity of the different TIMs should be taken into account in the application. The cause of failure is bond wire degradation due to increase in forward voltage without solder deterioration in all power cycling tests.