TABLE OF CONTENTS MEMS (micro electromechanical systems) based on semiconductor microfabrication play important roles for example in the periphery of IT systems. They are value-added but not cost effective in many cases. The reason is that MEMS products are versatile and of small volume. Since the technology is interdisciplinary and needs semiconductor fabrication, open collaboration to reduce development costs and common usage of facilities are needed for cost effective MEMS production. It is said that packaging is 80% of the cost of MEMS devices. Wafer process packaging is effective for the small volume production of MEMS because assembly of each separate chip is not required [1]. Electrical interconnection from the MEMS device in the encapsulated cavity or between MEMS and an integrated circuit can be made using electrical feedthrough in a glass. This can simplify the MEMS fabrication process. In the following, array MEMS with nanostructures, sophisticated MEMS using electrostatic levitation and application of functional materials such as AlN, PZT, SiC, CNT (carbon nano tube) to microsensors, microactuators and micro energy sources will be described.
The spherical 3-axis accelerometer has been developed by Ball Semiconductor Inc, collaborating with Tokimec Inc. and Tohoku Univ.[2]. As shown in Figure 1, a 1mm diameter spherical proof mass (ball) made of silicon is electrostatically levitated inside a shell with closed-loop control. The principle of the levitation using a capacitive displacement sensing and an...
