Physical Design for Surface-micromachined Mems

We are developing physical design tools for surfacemicromachined MEMS, such as polysilicon microstructures built using MCNC’s Multi-User MEMS Process service. Our initial efforts include automation of layout synthesis and behavioral simulation from a MEMS schematic representation. As an example, layout synthesis of a folded-flexure electrostatic combdrive microresonator is demonstrated. Lumpedparameter electromechanical models with two mechanical degrees-of-freedom link the physical and behavioral parameters of the microresonator. Simulated annealing is used to generate global optimized layouts of five different resonators from 3 kHz to 300 kHz starting with mixed-domain behavioral specifications and constraints. Development of the synthesis tool enforces codification of all relevant MEMS design variables and constraints. The synthesis approach allows a rapid exploration of MEMS design issues.