First-Level Packaging Considerations for the use of Electronic Hardware at High Temperatures

This chapter presents the fundamental material-related limitations of high-temperature operation of electronic systems caused by first-level packaging materials. It discusses the use of both plastic and hermetic packaging technology at elevated temperatures. The chapter focuses on the temperature limitations and dependencies of key thermal, mechanical, and electrical properties up to 200°C for the materials used in wires and wirebonds; die attach materials; leadframe materials; plastic encapsulants; hermetic case materials; lid seals; and lead seals. It discusses failure modes for case materials, the dependence of case material properties on temperature, and guidelines for materials selection to minimize any high-temperature concerns imposed by these materials on other materials around them. The gold eutectic metallurgical attachment is preferred for high-power circuits, because of its superior electrical and thermal conductivity. Modified polyimides are used for thermal and moisture stability, and have low coefficients of thermal expansion and high purity.