A Study on Alleviating Deformation of MEMS Structure and Prediction of Residual Stress in Surface Micromachining

Recently, the acceptance of micro electromechanical systems (MEMS) technology is growing in various areas such as medical, optical, automobile and telecommunication. In realizing the needs in MEMS, techniques derived from mechanical engineering plays an essential role in the determination of geometric design variables and process parameters, experiments in fabrication and the elastic and plastic deformation, the fatigue fracture, durability estimation under operational conditions. RF switch that shorts and opens a circuit of RF transmission line is a application that MEMS technique can contribute. During the fabrication process, the residual stress build up, which is caused by the thermal expansion coefficient mismatch between deposited materials, is unavoidable and leads to the deformation of structures. In order to cope with this problem, a finite element analysis was carried out to predict and optimize the residual stresses in a multi-layered structures and a new method to restrain deformation is proposed..