Surface measurement errors using commercial scanning white light interferometers
Surface measurement errors using commercial scanning white light interferometers
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DOI：
10.1088/0957-0233/19/1/015303
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Coupland, J. M.
中科院分区：
文献类型：
--
作者：
Gao, F.;Leach, R. K.;Coupland, J. M.
本文研究了商用扫描白光干涉仪在一系列测量任务中的性能。阶梯高度伪影用于研究仪器在不连续处的响应，而具有正弦和矩形轮廓的光栅用于研究表面梯度和空间频率的影响。将结果与轻敲模式原子力显微镜的测量结果进行比较，并参考已发表文献中提出的误差机制讨论差异。正如预期的那样，我们发现大多数仪器在接近不连续性的区域或表面梯度与物镜接收角相比较大的区域中使用时都会报告错误。然而，在其他发现中，我们报告了当表面梯度相当小时观察到的系统误差。尽管这些误差通常小于平均波长，但与仪器的垂直分辨率相比，它们非常显着，并且表明如果需要亚波长精度，则应谨慎使用当前的扫描白光干涉仪。
This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required.