Design of bulk micromachined suspensions

Abstract

Microsuspensions are very useful mechanical structures in microelectromechanical systems. The fabrication processes of microsuspensions, including front-side etching and back-side etching processes, have been studied extensively. Due to the restriction of the undercutting process, the front-side etching approach offers only limited patterns of microsuspension. The present study intends to develop a method to predict the possibility of fabricating microsuspensions on a (100) substrate through the front-side etching process. Microsuspensions with arbitrary shapes can be designed easily according to the proposed method. It is found that the formation of the microsuspensions predicted by the proposed technique agrees well with the experimental observation. The contribution of this paper is to provide a convenient tool to design microsuspensions fabricated through the front-side etching process. The application of the front-side etching process on microsuspensions will become more attractive. Thus the problems of having a large cavity on the substrate, longer etching time and larger die size caused by the back-side etching process can be prevented.