A novel analytical-based viewpoint for MEMS mass spring system: systematic design guideline for dimensional tolerance and footprint reduction powered by dimensionless analysis

Abstract

Mass-spring is one of the most used structures in sensors and actuators of MEMS technology, including accelerometers, gyroscopes, harvesters, etc. Some of the major design parameters of the structure are natural frequency and displacement sensitivity. The limitations of microfabrication processes should be considered in the design process. The optimized geometry topology can reduce the area occupied by the structure in the fabrication and increases the number of possible structures per wafer. This study aims to provide a novel systematic design and optimization of a MEMS mass-spring system by using a dimensionless design flowchart. Based on the dimensionless design, this algorithm provides the designer with the optimized dimensions of the mass-spring by following the provided dimensionless diagrams, taking into account stress, displacement sensitivity, natural frequency, and fabrication limitations. Also, the optimized dimensions of the mass-spring system are obtained using the dimensionless design flowchart with respect to the desired natural frequency and displacement sensitivity. In addition, genetic algorithms and dimensionless diagrams present a procedure to minimize the footprint of the structure while keeping the desired natural frequency and displacement sensitivity. Results demonstrate that up to a 3% change in both natural frequency and displacement sensitivity, leads to a 45% reduction in the structure area compared to the related literature of MEMS accelerometers.