Novel scanning system with error separation for high-accuracy profile measurement

This paper proposes a method based on a single-probe scanning system for measuring the profile error of an artifact. Our system employs the movement accuracy of a single sensor to achieve a virtual multi-sensor configuration that can function like a traditional multi-sensor. This novel virtual multi-probe scanning system and its corresponding method have the following benefits: (a) A high-accuracy profile can be reconstructed free of the guidance error of the scanning stage. The reconstructed profile has a very high lateral resolution, depending on the lateral resolution (mu m level) of the probe. (b) Sensor drift can be restrained using our method, based on the principle of differential reconstruction. The high steep profile can also be measured with a scanning system moving along the measuring direction, thus extending the measuring range. We developed the measurement system and tested the effects of noise, drift, and other factors on the reconstruction results. Finally, some optical surfaces were measured, and comparisons were made between the results obtained from our method and those of a Zygo interferometer. There was high agreement between the two methods, with a deviation of approximately 0.1 mu m.