Chip-level-microassembly Comb-drive XYZ-microstage with Large Displacements and Low Crosstalk

This paper presents a chip-level-microassembly comb-drive XYZ-microstage with large displacements and low crosstalk for the applications of scanning force microscope at cryogenic environment. The three-dimensional comb-drive XYZ-microstage, with no affection to the thermal variation, was accurately and orderly constructed with three components of a comb-drive XY-microstage for in-plane actuation, two comb-drive Z-actuators for out-of-plane actuation, and a base substrate using a chip-level-microassembly technology. This configuration can overcome the out-of-plane stroke-space limitation of conventional monolithic-wafer-based XYZ-microstages, and the crosstalk movements resulting from the coupling connection between in-plane and out-of-plane actuation units can be avoided. Additionally, we further conducted two aspects of designing the decoupling-motion structure and constraining the capacitance-decoupling crosstalk, to achieve low-crosstalk movements in the in-plane actuation unit. The folded-flexure springs with high stiffness were adopted to enhance the lateral stability of movable combs and improve the range of achievable strokes. Finally, the fabricated comb-drive XYZ-micro stage, as a promising three-dimensional scanner, was capable of providing large displacements of 28.3 µm into +X direction, 20.9 µm into -X direction, 5.8 µm into +Y direction, 22.1 µm into -Y direction, and 50.5 µm into Z direction, respectively.