LI Qi1, XV Hongyi1, JIN Rui2, XIE Gang1, GUO Qing1, SHENG Kuang1

 

(1. College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China; 2. Electrical Engineering

New Material and Microelectronics Department, State Grid Smart Grid Research Institute, Beijing 102211, China)

 

 

Abstract: Aiming at solving the turnoff failure of the IGBT device in application, the voltage stress, current stress, avalanche energy endurance and failure pattern of IGBT was studied under unclamped inductive switching (UIS) condition. Based on the UIS test circuit, the failure mechanism was discussed in detail. Aluminum wires were bonded on different location of IGBT bare chips separately during packaging. The UIS experiment was carried out on these chips based on selfassembled experimental platform. Advice on packaging improvement was proposed to avoid the influence of wire bonding on UIS failure. The experimental results indicate that the wire bonding introduced lateral resistance on the emitter metal pad of IGBT would cause the nonuniformity of resistance in paralleled IGBT cells and thus result in the current constriction in cells near bonding spots till failure. Therefore, the failure spots on the IGBT chip stick to the bonding spots.

 

Key words: insulated gate bipolar transistor (IGBT); unclamped inductive switching (UIS); failure analysis