Comparison study of algorithms and accuracy in the wavelength scanning interferometry

Muhamedsalih, Hussam; Gao, Feng; Jiang, Xiangqian

doi:10.1364/ao.51.008854

Cited by 22 publications

(14 citation statements)

References 15 publications

(21 reference statements)

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“…Therefore, a method is needed for evaluating the modulation frequency; such methods are based on a single-shot linescanning measurement technique: Fourier transform profilometry (FTP). FTP has been applied to perform rapid extractions of the instantaneous phase from a modulation interferogram pattern [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Development of a spatially dispersed short-coherence interferometry sensor using diffraction grating orders

2017

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Modern manufacturing processes can achieve good throughput by requiring that manufactured products be screened by better quality control exercised at a quicker rate. This trend in the quality control of manufactured products increases the need for process-oriented precision metrology capable of performing faster inspections and yielding valuable feedback to the manufacturing system. This paper presents a spatially dispersed short-coherence interferometry sensor using diffraction orders of the zeroth and first order for a diffraction grating introduced as a new compact system configuration for surface profile measurement. In this modified design, the diffraction grating acts as the beam splitter/combiner. Diffractions for the zeroth and first orders are represented by the reference and measurement arms, respectively, of a Michelson interferometer, which reduces the optical path length. This innovative design has been proven effective for determining the step-height repeatability in the sensor range from 27 nm to 22 nm for profiles spanning the step heights of the tested specimens.

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Section: Introductionmentioning

confidence: 99%

Development of a spatially dispersed short-coherence interferometry sensor using diffraction grating orders

2017

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“…A total of 256 spectral interferograms, each at a discrete wavelength, are captured from each of the Michelson objectives by their corresponding cameras. The two interferograms sets are then analyzed to acquire the surface topography under each respective probe using a suitable fringe analysis algorithm [15][16][17][18].…”

Section: Methodsmentioning

confidence: 99%

“…The method relies on wavelength scanning interferometry (WSI) [14][15][16] which can achieve measurement with axial resolutions approaching the nanometre [17] without the requirement for the mechanical scanning of either the sample or optics, unlike comparable techniques such as CSI. This lack of mechanical scanning opens up the possibility of using a dual-probe optics system to provide simultaneous measurement with two adjacent fields of view.…”

Section: Introductionmentioning

confidence: 99%

A method for inspecting near-right-angle V-groove surfaces based on dual-probe wavelength scanning interferometry

Zhang

Gao

Martin

et al. 2018

Int J Adv Manuf Technol

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High-angled structured surfaces such as micropyramidal arrays, V-grooves and lenslet arrays are widely used in industries. However, there is currently no effective way to inspect these microstructures, resulting in very high scrap rates. This paper presents a proof-of-principle demonstration of an optical system capable of measuring V-groove structures in a single measurement acquisition. The dual-probe wavelength scanning interferometry (DPWSI) system comprises dual probes, with orthogonal measurement planes. The calibration of the DPSWI system is the key to registering the relative locations of the dual measurement planes and allowing the surface topography to be correctly reconstructed. In order to achieve this, a custom calibration artefact was manufactured comprising focused ion beam etched features on two faces of a precision cube. The procedures for the characterisation of the artefact to generate reference topography, and the subsequent calibration of the DPWSI are described in full. A measurement example from a metallised saw tooth sample featuring near-right-angles grooves having a peak-to-valley height of 32 μm and nominal pitch of 25 μm is presented and compared with a result obtained using stylus profilometry. DPWSI is shown to obtain an areal dataset in a single acquisition and is able to better resolve peak/valley points compared with the stylus, which is limited by a 2-μm tip radius. Some lateral scale error is apparent in the final DPWSI results and a discussion of this in terms of the limitations surrounding the current calibration artefact is presented.

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“…proposed to analyze the spectral inteferogram, including phase shifting (temporal and spatial) [5], Fourier transform [6], Hilbert transform [7], and convolution [8]. The temporal phase shifting technique is independent on the neighbor pixels and provides accurate results, however, several frames are required to calculate the phase.…”

Section: Several Analysis Techniques Have Beenmentioning

confidence: 99%

Phase retrieval algorithm for line-scan dispersive interferometry

Tang

Kumar

Gao

et al. 2018

Sixth International Conference on Optical and Photonic Engineering (icOPEN 2018)

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The line-scan dispersive interferometry (LSDI) benefits from single-shot measurement in nature and has potential to perform in-line surface metrology. In this technique, the interference beam produced by the two arms of the interferometer is spatially dispersed by a diffraction grating along the rows (or columns) of the CCD pixels. In which case, a twodimensional spectral interferogram is generated. In this paper, fringe order determination is carried out to retrieve the more accurate phase information along the chromaticity axis of the interferogram and then the height map of the tested profile can be calculated with high resolution. Two standard artefacts have been evaluated using the developed LSDI and the experimental results are compared with that of phase slope method as well as the commercial instrument (Talysurf CCI 3000), which shows that better performance in measurement noise is achieved. Additionally, the measurement repeatability is significantly improved and demonstrated within sub-nanometer range.

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Comparison study of algorithms and accuracy in the wavelength scanning interferometry

Cited by 22 publications

References 15 publications

Development of a spatially dispersed short-coherence interferometry sensor using diffraction grating orders

Development of a spatially dispersed short-coherence interferometry sensor using diffraction grating orders

A method for inspecting near-right-angle V-groove surfaces based on dual-probe wavelength scanning interferometry

Phase retrieval algorithm for line-scan dispersive interferometry

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