Development of measurement system for microstructures using an optical fiber probe: improvement of measurable region and depth

The precise measurement of microstructures and other micron-sized materials has garnered considerable interest in recent years. However, a limited measurement region and the unavailability of miniaturized probes are the major issues in the realization of such systems. In this study, we have presented a system for microstructures based on a small-diameter optical fiber probe. In the improved measurement system, the prism was installed near the stylus shaft to expand the measurable region and depth. This means that there is no limitation on the width of the measurement object. The standard deviation of the repeatability of the point measurement in the X-, Y- and Z-directions was 31, 38 and 19 nm, respectively. A pin gauge with a diameter of 100 mu m was measured ten times for assessing the repeatability of measurements in the X- and Y-directions. The standard deviation of the diameter in these measurements was 25 nm. A step height standard with a calibrated height of 189.6 nm was measured ten times for assessing the repeatability of measurement in the Z-direction. The average height in these measurements was obtained as 200.2 nm with an expanded uncertainty of 49.3 nm (coverage factor k = 2). We confirmed that this system enabled accurate measurement in the X-, Y- and Z-directions.