The Fracture Reliability Model Of Polycrystalline Silicon Microcantilever

In recent years, enormous progress has been made in developing and designing new MEMS products. More and more products are coming in the market. The reliability of MEMS is becoming very important. It is necessary to identify the mechanisms of failure and develop the mathematical models for such mechanisms, so as to use these models to improve the reliability design for MEMS.The MEMS devices are loaded by static force when they are under the operation. Dynamic loads provided by the environment will affect them during transportation or operation. Especially, MEMS used in automotive and space applications will experience dynamic shocks during deployment and operation. Under shock loads, MEMS devices may fail in different models including fracture, stiction, and delamination. This paper focus on the reliability of the micro-cantilever subjected to both static and dynamic loads considering the failure of fracture.In the static analysis, Weibull model and stress and strength model are founded. In the dynamic analysis, the micro-cantilever was taken as a distributed-parameter system. The displacements and stresses of micro-cantilever are then formulated with the mode superposition method. Whether the cantilever failed due to fracture or not could be determined by the maximum stress. This method can be also used in other complicated MEMS structures and devices. Using interference theory of stress and strength in the mechanical field, the reliability model will be presented and it can predict the probability of the reliability of the cantilever under shock loads. It will help improve the design of MEMS.At last, the shock experiment is done based on the analysis and the theory model is modified by the data from the experiment. All those play an important role in the design and analysis of the reliability of MEMS.