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 ( comb-drive) and out-of-plane (parallel-plate) electrostatic actuators are employed for driving the stage to move independently along the XYZ directions, by +/- 12.5 mu m in the X and Y directions at an actuation voltage of 30 V and by 3.5 mu m in the Z direction at 14.8 V. The structures are designed to achieve highly decoupled motions by effectively suppressing cross-axis motion coupling. The open-loop positioning repeatability is determined to be better than 17.3 nm along all three axes.