Surface measurement errors using commercial scanning white light interferometers

By F. Gao, Richard Leach, J. Petzing, J. Coupland. 2007

235 citations recorded by the source corpus.

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.

Subfields: Computational Mechanics, Computer Vision and Pattern Recognition, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/efe98335815b017999699da837b24e5362cec2fc

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In Computational Mechanics

In Mechanical Engineering

Citations in the corpus

An insight into optical metrology in manufacturing (2020, unknown): “This kind of error was reported in the measurement of flat objects using SWLI [152, 155].”
Principles of interference microscopy for the measurement of surface topography (2015, unknown): “In other cases, average amplitude or Ra values measured with CSI have disagreed in some cases by asmuch as a factor of 2with respect to stylus measurements [196].”
Focus Variation – a Robust Technology for High Resolution Optical 3D Surface Metrology (2011, background): “Another report shows jumps or spikes of half the mean wavelength, which is reported more frequently as the surface gradient increases or when there is a step discontinuity [8].”
Modeling and simulation in tribology across scales: An overview (2018, background): “[388] f or white light interferometry and [389,390] for scanni g force microscopy).”