Improvement of dimensional measurement accuracy of microstructures with high aspect ratio with a spherical coupling fiber probe*

Abstract

A specially designed and developed spherical coupling fiber probe was proposed to improve the dimensional measurement accuracy of microstructures with high aspect ratio. The effectiveness of the proposed probe was verified through simulation and experiment. Our simulation results indicated that the maximum deformation was less than 40 µm during the measurement and, therefore, the shaft of the proposed probe did not touch the sidewall of a micro hole. Our experimental results indicated that a static centroid stability of 1.76 µm could be achieved with a resolution of 30 nm in directions X and Y, which meant that the special light path arrangement of the proposed probe overcame the shadowing effect and improved the dimensional measurement accuracy of microstructures with high aspect ratio. It was, therefore, concluded that the proposed probe was suitable for the dimensional measurement of microstructures with a high aspect ratio.