Novel substrate technology for IPM (intelligent power module) applications: Structural, thermal and electrical characteristics

Nowadays energy efficiency in power electronics has been drawn a more attention as the worldwide energy crisis was raised up. To achieve high efficiency, thermal engineering in the design and construction of power conversion modules (or Intelligent Power Modules) are crucial in their rating and applications because the operation temperature or junction temperature (which is a maximum temperature rise in the die at a given power dissipation) gives strong impacts on reliability, performance and efficiency. A module with a low thermal resistance can afford the operation at the high power densities for the same temperature rise or lower temperatures for fixed power densities. To build an efficient power module having lower thermal resistance, substrate having a high thermal conductivity as well as good electrical isolation and reliability should be selected as a packaging platform. In this paper, the novel substrate technology which is so called `Copper Bonded Metal Substrate´ technology has been developed for intelligent power module (IPM) applications. Without the assistance of an adhesive material, the copper is directly bonded to the dielectric layers which have a high thermal conductivity and low-CTE (Coefficient of Thermal Expansion). These properties make CBM substrate technology a strongest contender for a packaging platform in power module applications. Electrical and thermal characteristics of the CBM™ substrate have been investigated as well. Owing to the structural continuity of CBM™ structure, as well as the high thermal conductivity of dielectric layer which is up to ~5 W/m-K, the retardation of thermal resistance in the interface between the copper layer and base plate has been minimized. And computational simulation and experimental measurement of the thermal resistance of the functional power module which adopt the CBM™ substrate have been conducted. In addition, electrical insulating properties are enough to be affordable for - high voltage operation (over 700 Vrms) of the power modules with a low leakage current (<; 300 nA). The obtained results in which CBM™ substrate has high heat dissipating capability and high insulating properties have been proven for CBM™ technology to be suitable for power module applications.