Modeling and Analysis of a New Pressure Contact Package for High-Current Large-Die IGBTs

Megawatt-class power converters need insulated gate bipolar transistors (IGBTs) with kiloampere current ratings. Conventional IGBT power modules face difficulty to meet the reliability and over-current requirements due to bond wires, solder joint, and single-side cooling limitations. Press-pack IGBTs overcome these drawbacks, but demands extremely tight tolerance control in chip screening and matching, module parts manufacturing, and assembly. In this paper, a new pressure contact package for high-current large-die IGBTs is proposed, modeled, and experimentally studied to allow a simpler packaging process. A large IGBT die, many times the size of a typical IGBT die, is designed with a unique layout of multiple segmented emitter pads and a common gate pad. A patterned polymer positioning frame is placed onto the die. Metal contact spacers are placed in the openings of the frame to connect the emitter lid to the IGBT emitter sectors. A collector contact disc is placed between the IGBT die and the collector lid. Finite-element (FE) analysis is conducted to evaluate the mechanical and thermal performance of the new package. A 3300-V, 14-cm
²
active area, round-shape IGBT die is fabricated and packaged. Excellent electrical and thermal characteristics are demonstrated to validate the feasibility of the IGBT and package concept.