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

We investigate the failure modes of a comb-drive surface-micromachined microresonator that are caused by particulate contaminations. The microresonator structure is chosen as our research vehicle because it possesses all the primitive components found in many capacitive-based MEMS sensors and actuators. Process simulation is used to create the full-spectrum of defective structures caused by foreign particles. The generated defective structures are then classified based on their geometrical properties. Finite element analysis is used to understand the impact of these defects on the mechanical frequency response of the microresonator while HSPICE simulations are performed to determine the corresponding electrical misbehaviors within an acceleration measuring application. Simulation results show that particles can cause unwanted anchors, broken beams and welded comb fingers. However, the most interesting defects are broken comb fingers and lateral finger protrusions that only affect sensing capacitance. These defects lead to a very small increase or decrease in the shuttle mass. The mass change is so small that the mechanical frequency response of the resonator is virtually unchanged. However, the HSPICE simulations show that the change in output sensing voltage can be catastrophic.