Design and Experimental Evaluation of Transfer-Molded 650 V Super-Junction mosfet Power Module for Industrial Applications

This article presents a new transfer-molded design of a four-pack 650 V super-junction mosfet power module. This power module is designed for industrial applications, including solar energy converters and on-board chargers. In these applications, it is critical to reduce the stray inductance, package on-resistance, thermal resistance, volume, and cost of the power modules. These challenges are addressed by optimizing the module design, fabrication process, and selection of components and packaging materials. Eight super-junction mosfets, lead frames, and an SMD thermistor are soldered onto a direct bonded copper substrate, followed by a wire bonding and transfer molding process. The fabricated module exhibits low stray inductance, package on-resistance (∼16.3 mΩ), thermal resistance (∼0.26 K/W), and volume (∼43% reduction in comparison with a commercial counterpart). Moreover, the module reliability is successfully demonstrated by electrical isolation (ac voltage of 2,500 V), thermal cycling (–40 to 85°C), and power cycling (up to 100,000 cycles) tests, satisfying international standards.