Validation of transient dual interface measurement method of IGBT Rth-JC

The validity of the measurement method of junction-to-case thermal resistance of IGBT modules when applying the transient dual interface measurements (TDIM) proposed in JESD51-14 is studied in this paper. The Rth-JC can be determined either by the structure functions or the point of separation of the derivatives of two Zth-curves according to the standard in which evaluation method of the derivatives of two Zth-curves is suggested for devices with solder die-attach or small thermal junction-to-case resistance. The simulation and experiment results indicate that the TDIM method can be used for the IGBT modules but the evaluation method which determines Rth-JC by the point of separation of the corresponding structure functions is more accurate than the evaluation method by the derivatives of two Zth-curves recommended in JESD51-14.