Mumbai University > Electronics Engineering > Sem 8 > MEMS Technology

Marks: 6M

• A measure of their sensitive resonant frequencies generally provides a good indicator of device functionality, process repeatability, and geometric variation.
• By fabricating comb drive resonators at each die on a wafer, measuring their resonant frequencies, and then comparing their measured values, it is possible to reveal such non-uniformities.
• The resonant frequency of a comb-drive resonator is directly dependant on its spring constant and mass.
• Therefore, changes in its resonant frequency can be mathematically linked to changes in its geometry. Figure shown is a scanning electron microscope (SEM) image of a typical comb-drive resonator.
• Its movable central shuttle mass is supported by two sets of bifold springs. Applying a voltage at L or R will force the center mass towards the fixed electrostatic comb fingers.
• The underlying surface is grounded.
• The schematic given in Figure labels the critical dimensions and components of the comb-drive resonator.