Su Rong, Wang Yuhang, Coupland Jeremy, Leach Richard
Opt Express. 2017 Feb 20;25(4):3297-3310. doi: 10.1364/OE.25.003297.
Although coherence scanning interferometry (CSI) is capable of measuring surface topography with sub-nanometre precision, it is well known that the performance of measuring instruments depends strongly on the local tilt and curvature of the sample surface. Based on 3D linear systems theory, however, a recent analysis of fringe generation in CSI provides a method to characterize the performance of surface measuring instruments and offers considerable insight into the origins of these errors. Furthermore, from the measurement of a precision sphere, a process to calibrate and partially correct instruments has been proposed. This paper presents, for the first time, a critical look at the calibration and correction process. Computational techniques are used to investigate the effects of radius error and measurement noise introduced during the calibration process for the measurement of spherical and sinusoidal profiles. Care is taken to illustrate the residual tilt and curvature dependent errors in a manner that will allow users to estimate measurement uncertainty. It is shown that by calibrating the instrument correctly and using appropriate methods to extract phase from the resulting fringes (such as frequency domain analysis), CSI is capable of measuring the topography of surfaces with varying tilt with sub-nanometre accuracy.
尽管相干扫描干涉测量法（CSI）能够以亚纳米精度测量表面形貌，但众所周知，测量仪器的性能在很大程度上取决于样品表面的局部倾斜度和曲率。然而，基于三维线性系统理论，最近对CSI中条纹产生的分析提供了一种表征表面测量仪器性能的方法，并对这些误差的来源提供了相当深入的见解。此外，通过对精密球体的测量，提出了一种校准和部分校正仪器的方法。本文首次对校准和校正过程进行了批判性审视。采用计算技术研究在校准过程中引入的半径误差和测量噪声对球形和正弦形轮廓测量的影响。我们谨慎地以一种能让用户估计测量不确定度的方式来说明残余倾斜度和曲率相关误差。结果表明，通过正确校准仪器并使用适当的方法从所得条纹中提取相位（如频域分析），CSI能够以亚纳米精度测量具有不同倾斜度的表面形貌。
