Dynamic MEMS Characterization System Using Differential Phase Measurement Method

The wide variety of shapes, functions, and operational parameters of microelectromechanical systems (MEMS) moving into production requires high flexibility for any measurement instrument. A computer-controlled stroboscopic interferometer system is described in the paper for measuring out-of-plane motions of MEMS structures with nanometer resolution. This system introduces five-step phase-shifting interferometric measurement method with high accuracy and differential measurement mode by choosing a fixed area on the device as the reference point, which eliminates the effect of random errors efficiently and improves the measurement repeatability of the system. The repeatability of 10 measurements is 3.17 nm. The study on the dynamic behavior of a micro-resonator illustrates the powerful capabilities of the system.