Inductive fault analysis of surface-micromachined MEMS

The defects and the corresponding behavior caused by particle contaminants introduced into the fabrication of a combdrive surface-micromachined microresonator are investigated. The microresonator is chosen as a research vehicle since it possesses all the primitive elements used in many types of capacitive-based microelectromechanical systems (MEMS). Fabrication process simulation is used to predict all the possible defective structures caused by contaminants. The resulting defects are then classified based on their geometrical properties. Mechanical and electrical simulations are also used to determine the impact of defect classes on key mechanical and electrical characteristics of the microresonator. This analysis reveals that particles can cause various mechanical defects that include anchors, broken beams, and bridged comb fingers, all of which can have a significant impact on mechanical behavior. On the other hand, there are mechanical defects (e.g., a broken comb finger) that virtually have no effect on mechanical properties but can lead to catastrophic changes in electrical capability.