A new approach for the fabrication of micromechanical structures

Abstract

Many inherent features available in the CMOS process lend themselves to the fabrication of certain micromechanical structures for sensor applications. These micromechanical structures are fabricated by implementing unconventional layout designs in CMOS technology without altering the process sequence. A single post-processing etching step is introduced to form free-standing microstructures on a CMOS IC without affecting the circuitry formed on the chip, thus allowing micromechanical sensors to be produced with pertinent on-chip circuitry for signal conditioning. Polysilicon micro-bridges, sandwiched oxide microbridges and cantilevers are produced using this technique.