Assembled Comb-Drive XYZ-Microstage With Large Displacements and Low Crosstalk for Scanning Force Microscopy

This paper proposes and demonstrates a chip-level-microassembly comb-drive XYZ-microstage for providing large displacements and low crosstalk in scanning force microscopy applications at low temperatures. The three-dimensional structure of the comb-drive XYZ-microstage, consisting of an in-plane XY-microstage, two out-of-plane Z-actuators, and a base substrate, was accurately and orderly constructed using 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. The in-plane actuation unit of the XY-microstage can provide low-crosstalk movements in the X- and Y-directions, due to the design of the decoupling-motion structure and constraint of the capacitance-coupling crosstalk of the actuation voltages. Folded-flexure springs with high stiffness were adopted in the XYZ-microstage to enhance the lateral stability of movable combs and improve the range of achievable strokes. The assembled comb-drive XYZ-microstage could provide quite large displacements of 49.2 $\mu \text{m}$ , $27.9~\mu \text{m}$ , and $50.5~\mu \text{m}$ in the X-, Y-, and Z-directions, respectively. Furthermore, to demonstrate the feasibility of the fabricated XYZ-microstage, a magnetic resonance force microscopy measurement system was constructed using the scanning XYZ-microstage with a specimen of 1, 1-Diphenyl-2-picrylhydrazyl radical. The magnetic resonance force from the electron spin resonance excited in the specimen could be detected by scanning the specimen in a specific resonance region. The results demonstrate that the proposed microassembly with the optimized actuation-unit structure is a promising means of establishing a comb-drive XYZ-microstage with large displacements, low crosstalk, and high adaptability. [2021-0112]