Temperature Influence on the Accuracy of the Transient Dual Interface Method for the Junction-to-Case Thermal Resistance Measurement

The transient dual interface method (TDIM), proposed by the JEDEC 51-14 standard [1], determines the junction-to-case thermal resistance of power electronics with the separate point of two transient thermal impedance curves under different contact conditions. However, the influence of the junction temperature is not considered and this underestimates the actual value with earlier separation point. This phenomenon is presented first with experimental results at different junction temperatures. Electro-thermal finite element simulations and simulation with semiconductor physical behavior in the devices simulations are performed to explain the root reason. After that, the improved TDIM with the junction temperature compensation is proposed to improve the accuracy. The experimental results show that the improved TDIM improves the accuracy of about 9.5% for 600-V discrete IGBT devices.