Impact of Bond Wire Degradation on Thermal Estimation and Temperature Coefficient of IGBT Modules in Power Cycling Test

Decoupling the temperature effect on the on-state voltage (Vce) is essential when only the bond wire degradation of the insulated-gate bipolar transistor (IGBT) needs to be characterized in the power cycling test. This process entails the acquisition of thermal information and temperature coefficient, along with careful consideration of the effects of aging on them in turn. In this paper, the impact of bond wire degradation on them is examined, which corresponds to the analysis of the temperature dependence characteristics of Vce under two typical currents, the thermal sensing current and power cycling current. Moreover, the error associated with the existing temperature decoupling strategy is quantified theoretically. Based on this, a new decoupling scheme is proposed. The effectiveness of the corresponding analysis is validated based on the elaborate experiment design, a combination of degradation simulation, I-V characterization test, and thermal calibration. Additionally, the experimental results reveal that another factor, namely the linearity between on-state voltage and temperature, also can introduce errors into the decoupling process.

I. Introduction

The widespread application of power electronics and the expected lower energy cost have raised concerns about reliability, particularly regarding the key component, the insulated-gate bipolar transistor (IGBT) module due to its high failure rate [1]. In reliability analysis, the degradation characterization plays a crucial role as it not only enables effective identification of failure mechanisms but also influences subsequent prognostic analysis [2], [3]. Packaging reliability acts as a bottleneck that impacts the performance of the device [4]. Over the past two decades, a variety of studies have focused on this topic, employing the power cycling test as an effective tool [5]. Therefore, the degradation characterization in power cycling tests holds important significance.