A single-wafer-processed XY-stage fabricated with trench-sidewall doping and refilled-trench isolating technology

For nano-metric positioning and manipulation, a single-crystalline-silicon XY-stage is fabricated by using a double-sided bulk-micromachining technology. For defining different electrostatic actuators in one ordinary wafer (instead of SOI wafer), a trench-sidewall electric isolation method is developed. Previously insulator-refilled trench-bars are used to cut and isolate the different comb-drive actuating elements on the structural trench-sidewalls. Combined with the reverse-biasd isolation of p-n junctions along the boron-diffused trench-sidewall for comb-driving, individual actuators can be operated independently. For maximizing the actuating stroke that is limited by the fabricated minimal comb-gap, a two-segment comb with a gentle-curve transition is designed for both improving actuation-amplitude and avoiding side-instability of the stage. Under 23V actuating voltage, the moving stroke is about 10μm in each of the four directions. Compared with conventional comb structure, the new comb design contributes 70% improvement in driving amplitude. Nano pitches on PMMA film are recorded by an electric-heated SPM probe. Coated with PMMA film, the stage movement is precisely controlled, resulting in controllable nano recording. © 2006 IEEE.