Ageing Bonding Wires Equivalent Resistance Change Law Based on Temperature Distribution Coefficient

As the IGBT module is not constant under actual operating conditions, this induces abnormal fluctuations in the junction temperature and contributes to the aging of the IGBT module bond wires. This paper proposes an equivalent resistance analysis method for bond wires aging considering the temperature distribution coefficient and improves the accuracy of detection for the early stage of bond wires aging. At first, a grating fiber optic temperature sensor is used to capture the bottom of the chip, the 45° diffusion angle, and the substrate edge temperature measurement points to determine the value of the temperature distribution coefficient $\boldsymbol{k}$ . Then, the equation is introduced based on the values measured at the fixed temperature measurement points and the calculation principle of Cauer model, and then the value of $\boldsymbol{V}_{\boldsymbol{ce}}$ of the IGBT module is iterated backwards and split into two parts affected by temperature and bond wires aging. Finally, the amount of change in $\boldsymbol{V}_{\boldsymbol{ce}}$ due to bond wires aging is determined by separating the two according to the IGBT output characteristics in the DateSheet, and the amount of change in equivalent resistance of the bond wires is determined using the electrical parameters of the current operating conditions.