Massachusetts Institute of Technology

Coventor, Inc.

Raj K Gupta

Stephen D Senturia

Accurate characterization of microelectromechanical systems (MEMS) geometry is critical for device design and simulation, for material property extraction, and for post-fabrication trimming. According to the present embodiment, a method for characterizing parameters describing MEMS structures resulting from the fabrication process or process variations is presented. According to the prefered embodiment, experimentally obtained natural frequencies are compared with numerical simulations to identify unknown values of structural parameters or parameter variations. Further, the prefered embodiment teaches how electrostatically-driven laterally resonant comb-drive MEMS test structures with prescribed changes in spring width are used to characterize systematic variations in process offsets and sidewall angles. The disclosed technique is both in-situ and non-destructive.

Characterization of microelectromechanical structures

A fluid property sensor includes a substrate having a first electrode thereon, and a flexible member adjacent the substrate and the first electrode wherein the flexible member includes a second electrode. A signal generator generates a predetermined electrical signal across the first and second electrodes so that an electrostatic force is generated between the first and second electrodes and so that said flexible member deflects a predetermined distance. A measuring circuit measures an interval of time between the generation of the predetermined electrical signal and the deflection of the flexible member to the predetermined distance and determines a property of a fluid adjacent the flexible member based on the interval of time. For example, the sensor can be used to determine a viscosity of the fluid. Alternately, the fluid can be a compressible gas, and the sensor can be used to determine a pressure of the gas. Related methods are also discussed.

Growing community of inventors

San Francisco, CA, United States of America

Raj K Gupta