基板の概念設計と基板性能についての基本的検討 パワーデバイス用基板システムの設計とそのアセンブリプロセスに関する研究 （第１報）

Abstract

Power-control semiconductors are widely used in industrial applications. The development of power semiconductor such as insulated-gate bipolar transister enables much faster switching, higher current and higher voltage rating. While high-performance of the semiconductor is accompanied by an evolution of heat. A substrate system, therefore, is very important part to dissipate heat from the semiconductor.Design and assembling process substrates system for the semiconductor have been researched and developed. In this report, especially, a conceptual design and performance of the substrate is discussed through a calculation of thermal stress by finite element method and an analysis of its function. It was clarified that the design accepted region of initial performance of the substrate was bounded by a dielectric breakdown voltage, a current capacity and a thermal conductivity. The substrate is consisted of conductors and an insulator. The dielectric breakdown voltage is determined by thickness of ceramics insulator. The current capacity is determined by thickness of copper conductor. The thermal conductivity is determined by materials and thickness between conductor and insulator. Furthermore, it was found that maximum principal stress is generated at a corner of ceramics and copper conductor at the lowest temperature, and the stress occurence crack at the ceramics. A reliability of the substrate was dominated by thermal stress generated in ceramics under temperature cycles.