Thermal analysis and reliability assessment of power module under power cycling test using global- local finite element method

Abstract

Insulated gate bipolar transistor (IGBT) power modules have acquired fast switching and low conduction loss characteristics. Because of these electrical characteristics, the IGBT has been widely applied in power supplies, e.g. hybrid electric vehicle, wind power generation, etc. However, the IGBT during rapid transient operation under high power can cause the IGBT chip to lead high junction temperature and high temperature gradients. Furthermore, because of the coefficient of thermal expansion (CTE) mismatch between the various material layers, the bonding wires and the solder joints are subjected to thermo-mechanical stress which cause solder fatigue and bonding wire failure, and then affect the reliability of IGBT under actual operation conditions. A 3-D finite element (FE) model was established base on real test samples. The simulation results found that the maximum junction temperature 112.5 is observed at the middle of IGBT chip under the load current of 40 A. Then analyze the mechanical behaviors of IGBT, the structural simulation results show that under a cyclic power environment, the stress concentration within the wire, caused by the CTE mismatch between the wire and the IGBT chip. Therefore, the wire/chip interface is the weaker portion of the power module. Finally, according to the life prediction models of literatures, this paper assessed the reliability of bonding wire in order to investigate the effects of thermal stress and strain on reliability during power cycling test.

Modeling method for electrothermal cosimulation of high‐power IGBT

“…Besides, it is difficult to get the structure parameters inside the chip. Thus, the FEM modeling accuracy for IGBT is unsatisfactory, especially for the accurate description of electrical characteristics [9][10][11]. Based on the Technology computer aided design simulations, the V-I characteristics of IGBT at different temperatures were obtained in [12], which can be transformed into look-up table and applied to the IGBT electrical model.…”

Double wavelength combined electronic speckle pattern interferometry–moiré system for full-field strain analysis on electronic components

“…Numerical modeling can be applied to evaluate thermal field in electronic components 8 or to evaluate how a given thermal input determines deformations and stress concentration on the component as well as at the wire-to-chip interface. 9 However, it should be underlined that due to the high complexity of the modern electronic components and devices, many input data are required in order to have an accurate model or, as an alternative, several approximations have to be done that can affect the final accuracy of the simulation. Experimental methods can be a powerful tool to overcome these problems.…”