MEMS (micro electro mechanical systems) is the integration of mechanical elements, sensors, actuators, and electronics using batch-level microfabrication technology. It involves mechanical, electronic, material, optical, fluid and other disciplines. MEMS is a key technology related to the development of national science and technology, economic prosperity and national defense security. From aerospace technology to biotechnology, especially sensor technology, MEMS will have a huge impact. It is expected that the growth of the commercial and defense markets of MEMS is similar to that of IC technology. MEMS technology is destined to become a hallmark 21st century manufacturing technology with numerous and diverse applications.