Analysis and Evaluation of Surface Force Effects in Vibrating Fiber Probing System for 3-D Micro Structure Measurements

Abstract

This paper presents a measurement system for 3-D micro structure using an optical fiber probe equipped with a piezo element generating vibration. The optical fiber probe consists of a stylus shaft with a diameter of 3 µm and a glass ball with a diameter of 5 µm attached to the tip. The stylus is set so as to circularly move in a plane. The measurement principle involves the monitoring of the vibrational amplitude of the stylus to prevent adhesion of the stylus tip to the measured surface due to the surface force, and this amplitude is measured optically. In this research, the stylus characteristics are examined. The effects of the relative humidity and the surface roughness on the surface force are then evaluated. As a result, it is shown that the surface force increases remarkably when the relative humidity is greater than 40%, and there is no adhesion of the stylus tip to the measured surface due to the surface force in case of the stylus vibrational amplitude of over 0.5 µm. Also, the adhesion of the stylus tip cannot be observed in the 0.2 - 0.8 µm surface roughness range.