Electrical characteristics and reliability performance of IGBT power device packaging by chip embedding technology

With the current high demand for energy saving and low power consumption, numerous studies have been conducted to meet this requirement. Higher switch efficiency is one of the factors for power saving in power inverters and converters. Among the methods for improved switch efficiency, the modified package structure is one of the solutions. An embedded power module enables shortened transmitting routes and lower parasitic reactions, suggesting better power switching performance. Meanwhile, embedding allows the power devices to integrate active or passive devices above or beneath a component, leading to a three-dimensional packaging structure. This feature is also applicable in the integration of power devices because of its double side contact structure. Four dies that contain two insulated gate bipolar transistors and two diodes in this study were embedded and integrated in a carrier substrate to produce a next-generation power inverter module. The process began by attaching a die on a Cu lead frame by a SAC305 solder paste. This is followed by a lamination process to form a built-up dielectric layer on the Cu lead frame. The conducting vias and circuits were formed on the built-up dielectric layer by a UV laser and were metalized with sputtered seed layer and electroplating. The circuit layout can be revealed with subsequent etching processes by hatching another layer of electroplated Sn using UV laser. Finally, a layer of solder mask was printed to prevent electric shock on the surface layer. Structure and process features are discussed, and electrical testing and reliability tests are conducted in this paper.