Laminated, sacrificial-poly MEMS technology in standard CMOS

We present a micro-machining technology which enables MEMS fabrication on standard CMOS with very dense electrical/mechanical integration. Micro-mechanical structures are fabricated alongside circuits on standard 0.5-μm 3-metal CMOS dice using four maskless dry-etch steps. The resulting laminated beams are made of CMOS metal and dielectric layers. Multi-conductor mechanical structures can carry multiple signals for actuation and sensing. Narrow vertical and lateral gaps enable efficient XYZ electrostatic actuation and fine capacitive position sensing. Experiments show that mechanical structures can be integrated 1.5 μm away from signal-processing circuits. resulting in very low parasitics, good system performance, and small die size.