A MEMS Stage for 3-Axis Nanopositioning

Applications in micro and nanotechnologies require millimeter-sized devices that are capable of 3-axis positioning with motion ranges of micrometers and resolutions of nanometers. This paper reports on the design, fabrication, and testing of a MEMS-based 3-axis positioning stage. In-plane and out-of-plane electrostatic actuators (comb-drive and parallel-plate) are employed for driving the stage to move independently along the XYZ directions, by plusmn12.5 mum in the X and Y directions at an actuation voltage of 30V and by 3.5 mum in the Z direction at 14.8V. The structures are designed to achieve highly decoupled motions by effectively suppressing cross-axis motion coupling. Open-loop positioning repeatability is determined to be better than 17.3 nm along all three axes.