Plastic deformation of membrane with mesa silicon microstructure

Abstract

Membrane with mesa silicon microstructure is a fundamental structure widely used in micro-electro-mechanical system. However, it could be plastically deformed during high-temperature manufacturing process under certain load. This paper characterizes plastic deformation of vacuum sealed membrane with mesa silicon microstructure during 1100 $$^{\circ }$$źC microfabrication process. In order to study plastic deformation of membrane with mesa microstructures, microstructures with different dimensions are designed based on Von Mises yield criterion. Experimental results show that the plastic deformation is linear to diaphragm size and boss size. The effect of stiffness on plastic deformation is compared with the effect on elastic deformation. Plastic deformation is not only determined by stiffness but also by film thickness. The relationship between plastic deformation and Von Mises stress is further investigated. Plastic deformation and initial Von Mises stress shows a Boltzmann function relation.