A Bidirectional Two-Axis Electrostatic MEMS Positioning System

We report on the design, fabrication, and testing of a bidirectional two-axis MEMS positioning system that is used to move a stage. Sandia National Laboratories' MEMS foundry process was utilized for the fabrication of the device; this process incorporates five layers of polysilicon and four sacrificial layers of silicon dioxide. The positioning assembly consists of a pin and slotted-arm arrangement, wherein the pin is constrained between the slotted arms and the positioning of the pin is achieved by identical electrostatic drives on both axes. The electrostatic drives consist of a comb drive interfaced with a compliant-mechanism-based distance multiplier. The stage is connected to a cantilever arm extending from the positioning pin. The crosstalk between the X- and Y-axes was less than 0.3 ??m through displacements of ~30 ??m in both X- and Y-directions. The displacement shows a quadratic relationship with the applied voltage.