Surface and thickness measurement of transparent thin-film layers utilizing modulation-based structured-illumination microscopy

Xie, Zhongye; Tang, Yan; Zhou, Yi; Deng, Qinyuan

doi:10.1364/oe.26.002944

Cited by 33 publications

(4 citation statements)

References 22 publications

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“…Despite the capacities of spectroscopic ellipsometry for measuring the thickness, reflectance, and refractive index of thin films from sub-micron to nanometer scale [20,21], the application of the technique is limited by additional measurement time, a small thickness measuring range, and a complicated structure. SIM can obtain the surface profiles and film thickness by detecting the peaks of the modulation depth response curves [22,23]. It can detect micrometer-thick films but cannot be used for industrial inspection due to its slow detection speed.…”

Section: Introductionmentioning

confidence: 99%

Large-Area Thickness Measurement of Transparent Films Based on a Multichannel Spectral Interference Sensor

Huang,

Tu,

et al. 2024

Applied Sciences

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Thickness measurement of thin films is essential for quality control in the manufacturing process of the semiconductor and display industries. Real-time monitoring of film thickness during production is an urgent technical problem to be solved. In this study, a method for large-area thickness measurement of transparent films based on a multichannel spectral interference sensor is proposed. The sensor simultaneously acquires multichannel spectral interference signals through a combination of fan-out fiber optic bundles, detection probes, and an imaging spectrometer. The spectral data are calibrated and transformed into the wavenumber dimension, and then the power spectral density estimation method is used to demodulate the data frequency to swiftly derive the film thickness. The thickness measurement capacity of the proposed system is successfully validated on two standard film samples with a relative deviation of less than 0.38% and a relative standard deviation of less than 0.044%. The total spectral acquisition and calculation time for a single multichannel measurement was approximately 7.5 ms. The experimental results on polyimide films show that the measurement efficiency of the system is at least 4 times higher than that of the traditional system, indicating the potential of the multichannel spectral interference sensor for online monitoring in film production.

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Section: Introductionmentioning

confidence: 99%

Large-Area Thickness Measurement of Transparent Films Based on a Multichannel Spectral Interference Sensor

Huang,

Tu,

et al. 2024

Applied Sciences

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“…Three-dimensional defect detection methods can be divided into bright-field detection methods and dark-field detection methods. Bright-field detection methods mainly include optical coherence tomography [4] , confocal microscopy [5] , structured illumination microscopy [6] , etc., which can obtain rich surface information. However, due to the illumination background light, the defect detection sensitivity is rather low.…”

Section: Introductionmentioning

confidence: 99%

Defect detection of precision optics by bright-dark-field structured illumination microscopy

Zhang

Liu

2023

Conference on Infrared, Millimeter, Terahertz Waves and Applications (IMT2022)

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Defect has become the bottleneck that limits the further increase of energy output in high-power laser devices, accurate defect detection is important for defect evaluation and optical component quality control. The bright-field methods have the problem that the illumination background light affects the measurement sensitivity. The dark-field measurement methods can remove the illumination background light, and the defect detection sensitivity is higher. However, the surface shape information is also removed out, thus the defect depth information is missing. In addition, the axial resolution of defect detection under regular illumination is rather low due to the influence of out-of-focus light. In this paper, a defect detection method based on bright-dark-field structured illumination microscopy (BDSIM) is proposed. This method takes the advantage of the high axial resolution of structured illumination, reconstructs the surface shape by bright-field configuration, and detects the surface and subsurface defect by dark-field configuration. Experiments prove that our method can effectively measure the surface and subsurface defects with accurate depth information.

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“…A majority of research using optical methods was developed, those investigations usually target the transparent, metallic, oil, and aerostatic thin-film layers coated or deposited on the base layer. Kim and Kim [6] and Ghim and Kim [7] developed thin-film metrology using white-light interferometry, while Xie et al [8] applied structured illumination microscopy on the transparent thin-film measurement. Other methods based on the spectroscopic ellipsometry, which was proposed by Jellison et al [9], and Fresnel diffraction, which was brought up by Hassani and coauthors [10,11], were also developed.…”

Section: Introductionmentioning

confidence: 99%

Cosine Error-Free Metrology Tool Path Planning for Thickness Profile Measurements

Guo

Lee

2020

Journal of Manufacturing Science and Engineering

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This paper presents a novel thickness profile measuring system that measures double-sided thin pipe wall surfaces in a non-contact, continuous, cosine error-free, and fast manner. The surface metrology tool path was developed to align the displacement sensors always normal to the double-sided surfaces to remove cosine error. A pair of capacitive type sensors that were placed on the rotary and linear axes simultaneously scans the inner and outer surfaces of thin walls. Because the rotational error of the rotary axis can severely affect accuracy in thickness profile measurement, such error was initially characterized by a reversal method. It was compensated for along the rotational direction while measuring the measurement target. Two measurement targets (circular and elliptical metal pipe-type thin walls) were prepared to validate the developed measurement method and system. Not only inner and outer surface profiles but also thin wall thickness profiles were measured simultaneously. Based on the output data, the circularity and wall thickness variation were calculated. The thickness profile results showed good agreement with those obtained by a contact type micrometer (1 µm resolution) at every 6 degrees interval. The uncertainty budget for this measuring system with metrology tool path planning was estimated at approximately 1.4 µm.

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Surface and thickness measurement of transparent thin-film layers utilizing modulation-based structured-illumination microscopy

Cited by 33 publications

References 22 publications

Large-Area Thickness Measurement of Transparent Films Based on a Multichannel Spectral Interference Sensor

Large-Area Thickness Measurement of Transparent Films Based on a Multichannel Spectral Interference Sensor

Defect detection of precision optics by bright-dark-field structured illumination microscopy

Cosine Error-Free Metrology Tool Path Planning for Thickness Profile Measurements

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