Design of Silicon-Monolithic Flexure Stage with Selective Compliance

Abstract

This paper describes a design procedure of the linear-motion stage that has silicon monolithic structure and flexure beams suspend the stage. Single crystal silicon is appropriate for the structural material of miniaturized mechanism. However, the anisotropic properties and cleavage should be taken into account at the design stage. In addition, the manufacturing process has strong effects on the final strength because silicon is brittle material and sensitive to the flaw such as chipping. The design consideration is concluded as that the cleavage plane, {111} plane, should be arranged apart from the direction of the tensile stress to compromise both the fracture strength and compliance to achieve accurate motion. Also, the crystal direction <100> should be aligned along the tensile stress to obtain long stroke. The prototypes, size of 30×30mm, were prepared with deep reactive ion etching (DRIE) and its compliance was examined.