Integrated microelectromechanical systems in conventional CMOS

Electrostatically actuated microstructures with high-aspect-ratio laminated-beam suspensions are fabricated using conventional CMOS processing followed by a sequence of maskless dry-etching steps. The metallization and dielectric layers, normally used for electrical interconnect, now serve a dual function as a structural layer. The post-CMOS microstructural reactive-ion etch produces near vertical sidewalls, enabling micromechanical beam widths and gap spacings down to 1.2 μm. The process is tailored for design of lateral electrostatic actuators and sensors integrated with 0.5 μm CMOS. The fabricated x-y-z microstage devices demonstrate the technology for future use in inertial sensor and probe-based data storage system applications