Thickness measurement of dielectric films by wavelength scanning method

Köysal, Oğuz; Önal, Duygu; Özder, Serhat; Ecevit, F. Necati

doi:10.1016/s0030-4018(02)01203-8

Cited by 33 publications

(11 citation statements)

References 8 publications

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“…erefore, after putting equations ( 6) and (7) in equation ( 5), there is only one unknown |A 2 B 1 ��→ |. According to equation ( 4), the back surface depth data corresponding to each pixel of the rear surface can be estimated.…”

Section: Estimation Of Transparent Materials Surface Pointsmentioning

confidence: 99%

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[Retracted] Detecting Distance between Surfaces of Large Transparent Material Based on Low‐Cost TOF Sensor and Deep Convolutional Neural Network

Zou

Zhang

et al. 2021

Advances in Materials Science and Engineering

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Detecting distance between surfaces of transparent materials with large area and thickness has always been a difficult problem in the field of industry. In this paper, a method based on low-cost TOF continuous-wave modulation and deep convolutional neural network technology is proposed. The distance detection between transparent material surfaces is converted to the problem of solving the intersection of the optical path and the transparent material’s front and rear surfaces. On this basis, the Gray code encoding and decoding operations are combined to achieve distance detection between surfaces. The problem of holes and detail loss of depth maps generated by low-resolution TOF depth sensors have been also effectively solved. The entire system is simple and can achieve thickness detection on the full surface area. Besides, it can detect large transparent materials with a thickness of over 30 mm, which far exceeds the existing optical thickness detection system for transparent materials.

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Section: Estimation Of Transparent Materials Surface Pointsmentioning

confidence: 99%

“…Direct optical methods include grating spectroscopy and light triangulation. Grating spectroscopy is designed based on the principle of grating spectroscopy [7]. e system uses white light illumination.…”

Section: Introductionmentioning

confidence: 99%

[Retracted] Detecting Distance between Surfaces of Large Transparent Material Based on Low‐Cost TOF Sensor and Deep Convolutional Neural Network

Zou

Zhang

et al. 2021

Advances in Materials Science and Engineering

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“…32,40,41 As a final shortcoming of broadband non-resonant methods, which is of our third concern in this paper, the sample thickness is assumed to be precisely known. [12][13][14][15][16] Spectroscopic ellipsometry, 42 wavelength scanning, [43][44][45] spectral reflectometry/interferometry, [46][47][48][49][50] and full spectra fitting techniques [51][52][53] can be utilized for determining the sample thickness. Ellipsometry technique may not be so accurate if angle arrangement is not so precise.…”

Section: Introductionmentioning

confidence: 99%

Microwave method for reference-plane-invariant and thickness-independent permittivity determination of liquid materials

Hasar

Kaya

Bute

et al. 2014

Review of Scientific Instruments

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An attractive transmission-reflection method based on reference-plane invariant and thickness-independent expressions has been proposed for accurate and unique retrieval of complex permittivity of dielectric liquid samples. The method uses both branch-index-independent expressions and a restricted solution set for determining unique and fast complex permittivities. A 2D graphical method has been applied to demonstrate the operation and validation of the proposed method. A uncertainty analysis has been performed to monitor how the accuracy of the proposed method can be improved by a correct selection of sample holder properties. Scattering parameter measurements of two tested reference liquids (distilled water and methanol) have been carried out for comparison of various techniques with the proposed one when the reference-planes and sample thickness are not precisely known. We note from the comparison that whereas other techniques are seriously affected by imprecise knowledge of both reference-planes and sample thickness, the proposed method removes this restriction.

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“…Ellipsometry, for example, as well as reflectance and transmittance spectroscopy, recover the optical properties and thickness of a film from interference effects that are apparent when measurements are done over some spectral range [1][2][3]. Single wavelength techniques using coherent light sources can also provide information about optical thickness changes.…”

Section: Introductionmentioning

confidence: 99%

Laser beam diffraction at the edge of a film and application to thin film metrology

Touaibia

Haché

2013

Appl. Opt.

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The thickness change of a film is measured optically using self-interference of a single laser beam incident at the edge of the film. Theory suggests that when a half-plane phase shift is applied to a Gaussian laser beam, interference fringes appear in the near and far field, in which position varies with the amount of phase shift. By measuring fringe pattern displacement, we demonstrate detection of thickness changes in chitosan films induced by temperature rises of a few degrees centigrade. With a laser at 543 nm, the minimum detectable thickness change is 0.8 nm in ideal conditions (quarter wave films), corresponding with a phase shift of 0.02 rad, and the minimum detectable film thickness is ∼30 nm. Potential use for surface temperature measurements is discussed.

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Thickness measurement of dielectric films by wavelength scanning method

Cited by 33 publications

References 8 publications

[Retracted] Detecting Distance between Surfaces of Large Transparent Material Based on Low‐Cost TOF Sensor and Deep Convolutional Neural Network

[Retracted] Detecting Distance between Surfaces of Large Transparent Material Based on Low‐Cost TOF Sensor and Deep Convolutional Neural Network

Microwave method for reference-plane-invariant and thickness-independent permittivity determination of liquid materials

Laser beam diffraction at the edge of a film and application to thin film metrology

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