Novel IGBT module design, material and reliability technology for 175°C continuous operation

One solution for increasing output power in general purpose inverters is raising the operation temperature of Insulated Gate Bipolar Transistor (IGBT) modules by junction max temperature (T_jmax) =175°C against conventional T_jmax=150°C. However, the main problem for T_jmax=175°C operation is decreased the power cycling (P/C) capability caused by higher temperature. In this paper, we investigated the failure mechanisms of P/C test at T_jmax=175°C. From these detailed investigations, the failure modes of IGBT module are dominated by three joint parts under three categorized temperature regions. By using these results, we have developed three new technologies to achieve higher P/C capability: (a) New Al alloy bonding wire with higher fatigue capability, (b) High strength solder at high temperature, (c) New die electrode metallization with higher strength under high temperature and lower thermal stress between Si die and Al wire. With these technologies, our new IGBT module has the excellent P/C capability of continuous operation at T_jmax=175°C and longer lifetime compared with the conventional one.