Development of Three-Dimensional Microstages Driven by Comb Actuators (Evaluation of Basic Performance Using Atomic Force Microscope)

Abstract

Three-dimensional (3D) microstages driven by electrostatic comb actuators that provide continuous motion along three axes (x, y and z) were fabricated and evaluated using AFM (atomic force microscope). The 3D microstage consisted of sets of traveling tables, suspension systems, and comb actuators. Support suspensions were adoped to support two sets of comb actuators to exclude the interferences between the combs and to increase the displacement of the traveling table. The 3Dmicrostages were fabricated in a 20-μm-thick device layer on an SOI (silicon on insulator) wafer by using DRIE (deep reactive ion etching). An AFM was then used to operate the 3D microstage as its scanning devise. By measuring the grating on the traveling table, the relation between the displacement and driving voltage on each comb actuator was examined. The displacement of traveling table was 5μm in the y direction at a driving voltage of 40 to 225 V, and was 4.8μm in the x direction at 70 to 140 V. The displacement in each x and y direction is proportional to the 1.8th and 1.5th power of the driving voltage on each comb actuator, respectively. No hysteresis was found in the motion of the traveling table.