A Temperature-Insensitive Micromachined Resonant Accelerometer with Thermal Stress Isolation

Micromachined resonant accelerometers, especially those devices fabricated by silicon on glass technology, suffer from temperature drift caused by inherent thermal stress. This paper introduces two methods to attenuate the effect of thermal stress. The locations of the bonding anchors are first optimized in layout design to reduce the thermal stress effect along the acceleration-sensitive axis. Moreover, the glass substrate is designed as a dedicated shape to isolate the thermal stress generated during the die attach process. Experimental results on several prototype accelerometers show that the differential temperature sensitivity is reduced to 10.5 μg/°C and the 1-hour bias stability reaches 0.7 μg.