COMPARISONS OF ANCHOR DESIGNS FOR MEMS RESONANT MASS SENSORS

摘要

The anchor design for resonant mass sensor cantilevers has an important effect on structural dynamic behavior. We investigated five anchor designs and determined their effect on static deflection as well as resonant frequency. The first two designs are the simplest and most commonly used. The third and fourth designs, observed in the literature, add material to the anchor pillar by encapsulating sacrificial material. The fifth design, one of our own, adds two "feet" that extend alongside the cantilever. Static deflection under an applied uniform pressure was predicted using finite element analysis. Resonant frequencies for the first several vibration modes were also predicted. The results suggest that the anchor rigidity has a significant effect on static deflection. The most effective design had a static deflection approximately one half of that for the simplest design. The effect on resonant frequency is slightly more modest but still significant.