Packaging Technology for High Temperature Capacitive Pressure Sensors

Abstract

High temperature pressure sensors are critical sensing elements for the next generation of intelligent aerospace engine technology, as well as long-term exploration missions to Venus, where the surface temperature is 485°C. Various high temperature pressure sensors based on different sensing mechanisms are under development at the NASA Glenn Research Center. In order to test long-term performance and reliability of these sensors in a high temperature environment, and eventually commercialize these sensors, high temperature durable and long-term reliable packaging is essential. A prototype packaging technology for micro-sensors designated for applications in high temperature and high differential pressure environments has been developed and reported previously. Packaged high temperature silicon carbide pressure sensors have been successfully tested between room temperature and 500°C. This paper reports an improved version of this packaging technology and testing results of a packaged commercial Si capacitive pressure sensor at elevated temperatures. The parasitic parameters of the packaging are electrically characterized from room temperature to 500°C at 120Hz, 1kHz, 10kHz, and 100kHz. This packaging is primarily designed for high temperature capacitive pressure sensors, but it also applies to other high temperature sensors, especially those for high differential pressure environments.