LF-OCT Based Non-Destructive Testing for IGBT Module

Insulated gate bipolar transistor (IGBT) modules are key components in power electronic converters. The wire-bond packaging failures of IGBT module, such as bond wire related failures, will affect the reliability of the IGBT modules. Therefore, the reliability issues of the wire-bond IGBT module are worth being concerned. In this paper, a non-contact and non-destructive testing technology capable of quantitatively measuring the shape and size of the critical components of IGBT module is proposed. The proposed technology is based on the novel line-field optical coherence tomography (LF-OCT), which can capture a whole B-scan map in a single-shot fashion. The LF-OCT system is capable of micrometre imaging resolution and fast data acquisition, which are suitable for the non-destructive testing (NDT) of IGBT modules. The results indicate that the LF-OCT system has been successfully applied to inspect the critical components in the IGBT module. The mechanical parameters of the components can be provided accurately by the LF-OCT system.