Aerogel for Microsystems Thermal Insulation: System Design and Process Development

Extreme miniaturization in the microelectronics component market along with the emergence of system-on-chip applications has driven interest in correspondingly small-scale thermal management designs requiring novel material systems. This paper concentrates on aerogel, which is an amorphous, nanoporous dielectric oxide fabricated through a sol-gel process. Its extremely high porosity leads to very low thermal conductivity and dielectric constants. Significant research has been devoted to its electrical properties; however, there are several emerging applications that can leverage the thermal characteristics as well. Two promising applications are investigated in this paper: a monolithically integrated infrared sensor that requires thermal isolation between sensor and silicon substrate, and an ultra-miniature crystal oscillator device which demands thermal insulation of the crystal for low-power operation. This paper identifies the potential benefits of aerogel in these applications through system modeling, demonstrates aerogel’s compatibility with standard low-cost microfabrication techniques, and presents results of thermal testing of aerogel films compared with other microelectronics insulators and available data in the literature. The goal is to explore system thermal design using aerogel while demonstrating its feasibility through experimentation. The combination of numerical simulations, Bayesian surrogate modeling, and process development helps to refine candidate aerogel applications and allow the designer to explore thermal designs which have not previously been possible in large-scale microelectronics system production.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.