Fall 2010 IAB
September 15 to 17

Plenary 2: Matthew Chan


MEMS Sensors in the Built Infrastructure - Bonding Chips to Metals via SLID

Complex engineering systems ranging from internal combustion engines to geothermal and oil wells require specialized sensors to monitor conditions such as strain, pressure, acceleration, and temperature to improve efficiency in what may be high temperature, corrosive, harsh environments. These systems are typically made from metals and the sensors used to monitor them are typically fabricated on substrates of silicon carbide, or aluminum nitride. There is a sizeable thermal expansion mismatch between these metals and ceramics and so a robust packaging and bonding process is required, capable of mitigating thermal strains and surviving high operating temperatures while interfacing sensors with the systems.

In this project, the solid-liquid interdiffusion (SLID) bonding process is used for the joining of silicon carbide to stainless steel, using the gold-tin metal system. This process allows for bonding at temperatures below the final operating temperature of the system. A finite element simulation of the thermally induced stresses resulting from bonding and operation is performed. The diffusion bonding process is developed, conducted, characterized and evaluated for strength and robustness in harsh environments.