Dynamic MEMS Measurement Using a Strobed Interferometric System with Combined Coherence Sensing and Phase Information

While computer modeling of MEMS systems is becoming increasingly sophisticated, the delicacy and complexity of many MEMS components requires accurate metrology of the final devices to assure proper performance. Stiction, motion versus drive signal, shape changes during actuation, angular repeatability, and resonant frequencies are all items of interest. By obtaining topographic information as the drive signal phase, frequency, and voltage are varied, MEMS devices can be fully characterized over their range of operation. Strobed holographic interferometry has been employed for more than 25 years to characterize a variety of vibrating structures. Only recently, however, has strobed illumination been combined with more sophisticated interferometric techniques to produce quantitative data for a large class of moving devices.