Investigation of stress rupture properties of micro beams using the piezoresistive effect

Beam structure is widely used for MEMS (Micro-electromechanical Systems) design, the mechanical properties of beam structure are of great importance to guide the design of MEMS devices. Among the many properties, stress rupture properties are studied in this paper. The sensor based on piezoresistive effect with a specially designed cross-beam structure is proposed for stress rupture properties measurement. Finite element method (FEM) is applied to calculate the stress distribution on the beam based on the sensor output. It is found that the maximum tensile stress for the beam at the fracture moment is far less than silicon yield and fracture strength. Compared with other mechanical testing methods, the proposed method is much easier to be implemented and compatible with MEMS sensor production.