Methodology for integrated MEMS designs

A design methodology and CAD infrastructure has been developed to support integrated fabrication processes that combine silicon-gate MOS with double-poly surface micromachining. To facilitate the re-use of existing circuit designs, circuit layout rules closely resemble those defined by the MOS Implementation System (MOSIS). Sensor/actuators are laid out on an independent set of abstract layers which can be automatically adapted to meet the photomask requirements of different processes. A closed-loop, micromotor control system and an integrated (MEMS/NMOS) micromechanical shear stress sensor have served as the first test cases for the design system. The former application exercised the schematic design capability, which features mixed-signal behavioral modeling. The latter device has driven the development of the physical design capability, and the first lot of wafers yielded functional devices. The methodology can be readily extended to support a MEMS/CMOS process that is under development