The first MIT 600 V/450 a IGBT module for EV/HEV applications

Abstract

Nowadays, more than 180 countries including China, Japan, EU and others have signed the Kyoto Protocol, then “Energy-saving and Carbon reduction” becomes a popular slogan and an important mission to protect the environment and to pursue the national sustainability. Taiwan government is making many environmental policies as well for driving the people to purchase the eco-products like electric car, hybrid car and household appliances to reach the goal of Carbon reduction, and the industries are also actively involved in the mass production of the key components such as high power IGBT modules for EV/HEV, intelligent power module (IPM) for air-conditioner, and MOSFET SiP modules for the power management of consumer electronics and hand-held machine tools. The first 600 V/450 A IGBT module for EV/HEV application developed by ITRI was announced in this work. The module was composed of IGBTs and freewheel diodes (FWD), firstly 2 IGBTs and 2 FWDs were attached on one Al2O3 direct bonded copper (DBC) substrate by a Pb-free solder perform with a thickness of 100 μm in a vacuum reflow oven, and 3 DBCs were then soldered on a Cu baseplate by a solder perform as well. After cleaning, a heavy Al wire was used to connect the devices and DBCs, and subsequently the housing was adhered to the Cu baseplate by an adhesive. Finally, a Si gel with a dielectric strength higher than 10 kV/mm was poured for insulation and then agglutinated by heating. The process conditions were optimized in this study, a die shear strength higher than 20 MPa was acquired after optimizing the reflow profile, and a design of experiments (DoEs) plan was executed to obtain a pull strength higher than 800 g for the heavy Al wire bonding. After temperature cycling for 1000 times, the loss of the strengths was less than 20%, and the long-term reliability of the power module was verified.