**5. Conclusion**

106 Microelectromechanical Systems and Devices

(a) Profile at the second phase

(b) Profile at the ninth phase

Fig. 22. Dynamic profile measurement

This chapter has discussed several optical methods to realize MEMS characterization, including dimensional (static) and moving (dynamic) properties analysis. Two measuring systems are introduced. NMM based system combines nano-measuring machine with high positioning accuracy and microscopic interferometers. PSI, WLI, WLPSI are applied in the system to measure the dimensional parameters. MMA combines video microscopy, stroboscopic illumination and special algorithms. It employs two kinds of nondestructive methods - computer microvision for in-plane motion measurement and phase shifting interferometry for out-of-plane motion measurement. This system can test the threedimensional motions and dynamic profiles with nanometer accuracy.
