Theoretical limits on the freestanding length of cantilevers produced by surface micromachining technology

To determine the maximum possible length of freestanding micromachined cantilevers, in this paper we provide a theoretical analysis of three important forces on cantilevers, namely acceleration, Casimir and Coulomb forces. The analysis provides theoretical limits to cantilever lengths separate from the well-known effects of surface adhesion and capillary collapse. This analysis offers an insight into the problem of in-use stiction in microstructures, which is a major source of functional failure in dynamic micromechanical systems. In this paper we conclude with a table that lists the maximum free standing length of microstructures that would offer reliable operation without stick-slip motion, excluding the possible effects of surface adhesion.