Advances in Electronic Packaging Technologies To Temperatures as High as 500°C

Advances in silicon-on-insulator (Sol) iniregrated circuit technology and the steady development of wider band gap semiconductors like silicon carbide are enabling the practical deployment of high temperature electronics. High temperature civilian and military elecr'ronics applications include distributed controls for aircrajt, automotive electronics, electric vehicles and instrumentation for geothermal wells, oil well logging and nuclear reactors. In addition, while integrated circuits are key to the realization of complete high temperature electronic systems, passive components including resistors, capacitors, magnetics and crystals are also required. Electronic components from all of these categories exist, in varying degrees, for temperatures up to 500°C. However, one of the greatest hindrances to making individual componlents more reliable is the approach used to package them. Similarly, one of the greatest hindrances to integraiting individual components together into a system is the understanding of harsh environment packaging techn,iques and materials selection. This paper will address the issue of electronics packaging for harsh environment applications for a variety of packaging levels. We will begin by looking at the common failure mechanisms associatled with packaging microcircuits at the integrated circuit die level as well as packaging means for individual passive components. With these failure mechanisms identijfed, we will consider altemate materials selection choices and-fabrication approaches that will permit electronic systems to be packaged for much higher temperature operating environments than are generally possible with traditional methods. We will also examine packaging options at the printed wiring board level, including high temperature substrate materials, interconnect metallization, solders and braze materials.