Characterisation of oxide layers on technical copper based on visible hyperspectral imaging

The detection and characterisation of oxide layers on metallic copper samples plays an important role for power electronic modules in the automotive industry. However, since precise identification of oxide layers by visual inspection is difficult and time consuming due to inhomogeneous colour distri...

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Main Authors: Jan Stiedl, Georgette Azemtsop M., Barbara Boldrini, Simon Green, Thomas Chassé, Karsten Rebner
格式: 文件
语言:English
出版: IM Publications Open 2019-06-01
丛编:Journal of Spectral Imaging
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在线阅读:https://www.impopen.com/download.php?code=I08_a10
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author Jan Stiedl
Georgette Azemtsop M.
Barbara Boldrini
Simon Green
Thomas Chassé
Karsten Rebner
author_facet Jan Stiedl
Georgette Azemtsop M.
Barbara Boldrini
Simon Green
Thomas Chassé
Karsten Rebner
author_sort Jan Stiedl
collection DOAJ
description The detection and characterisation of oxide layers on metallic copper samples plays an important role for power electronic modules in the automotive industry. However, since precise identification of oxide layers by visual inspection is difficult and time consuming due to inhomogeneous colour distribution, a reliable and efficient method for estimating their thickness is needed. In this study, hyperspectral imaging in the visible wavelength range (425–725 nm) is proposed as an in-line inspection method for analysing oxide layers in real-time during processing of copper components such as printed circuit boards in the automotive industry. For implementation in the production line a partial least square regression (PLSR) model was developed with a calibration set of n = 12 with about 13,000 spectra per sample to determine the oxide layer thickness on top of the technical copper surfaces. The model shows a good prediction performance in the range of 0–30 nm compared to Auger electron spectroscopy depth profiles as a reference method. The root mean square error (RMSE) is 1.75 nm for calibration and 2.70 nm for full cross-validation. Applied to an external dataset of four new samples with about 13,000 spectra per sample the model provides an RMSE of 1.84 nm for prediction and demonstrates the robustness of the model during real-time processing. The results of this study prove the ability and usefulness of the proposed method to estimate the thickness of oxide layers on technical copper. Hence, the application of hyperspectral imaging for the industrial process control of electronic devices is very promising.
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spelling doaj.art-1fec9bb5d0ea4d8db7469edd8845754f2022-12-22T01:54:50ZengIM Publications OpenJournal of Spectral Imaging2040-45652040-45652019-06-0181a1010.1255/jsi.2019.a10Characterisation of oxide layers on technical copper based on visible hyperspectral imagingJan Stiedl0Georgette Azemtsop M.1Barbara Boldrini2Simon Green3Thomas Chassé4Karsten Rebner5University of Tuebingen, Institute of Physical and Theoretical Chemistry, Auf der Morgenstelle 18, 72076 Tuebingen, Germany; Reutlingen University, Process Analysis & Technology, Alteburgstrasse 150, 72762 Reutlingen, Germany; Robert Bosch GmbH, Automotive Electronics, Postfach 1342, 72703 Reutlingen, GermanyReutlingen University, Process Analysis & Technology, Alteburgstrasse 150, 72762 Reutlingen, GermanyReutlingen University, Process Analysis & Technology, Alteburgstrasse 150, 72762 Reutlingen, GermanyRobert Bosch GmbH, Automotive Electronics, Postfach 1342, 72703 Reutlingen, GermanyCenter for Light-Matter Interaction, Sensors & Analytics (LISA+), Auf der Morgenstelle 15, 72076 Tuebingen, GermanyReutlingen University, Process Analysis & Technology, Alteburgstrasse 150, 72762 Reutlingen, GermanyThe detection and characterisation of oxide layers on metallic copper samples plays an important role for power electronic modules in the automotive industry. However, since precise identification of oxide layers by visual inspection is difficult and time consuming due to inhomogeneous colour distribution, a reliable and efficient method for estimating their thickness is needed. In this study, hyperspectral imaging in the visible wavelength range (425–725 nm) is proposed as an in-line inspection method for analysing oxide layers in real-time during processing of copper components such as printed circuit boards in the automotive industry. For implementation in the production line a partial least square regression (PLSR) model was developed with a calibration set of n = 12 with about 13,000 spectra per sample to determine the oxide layer thickness on top of the technical copper surfaces. The model shows a good prediction performance in the range of 0–30 nm compared to Auger electron spectroscopy depth profiles as a reference method. The root mean square error (RMSE) is 1.75 nm for calibration and 2.70 nm for full cross-validation. Applied to an external dataset of four new samples with about 13,000 spectra per sample the model provides an RMSE of 1.84 nm for prediction and demonstrates the robustness of the model during real-time processing. The results of this study prove the ability and usefulness of the proposed method to estimate the thickness of oxide layers on technical copper. Hence, the application of hyperspectral imaging for the industrial process control of electronic devices is very promising.https://www.impopen.com/download.php?code=I08_a10hyperspectral imagingpushbroom imagingcopper oxideoxide layer thicknessmultivariate analysispartial least square regressionpredictionreflectance
spellingShingle Jan Stiedl
Georgette Azemtsop M.
Barbara Boldrini
Simon Green
Thomas Chassé
Karsten Rebner
Characterisation of oxide layers on technical copper based on visible hyperspectral imaging
Journal of Spectral Imaging
hyperspectral imaging
pushbroom imaging
copper oxide
oxide layer thickness
multivariate analysis
partial least square regression
prediction
reflectance
title Characterisation of oxide layers on technical copper based on visible hyperspectral imaging
title_full Characterisation of oxide layers on technical copper based on visible hyperspectral imaging
title_fullStr Characterisation of oxide layers on technical copper based on visible hyperspectral imaging
title_full_unstemmed Characterisation of oxide layers on technical copper based on visible hyperspectral imaging
title_short Characterisation of oxide layers on technical copper based on visible hyperspectral imaging
title_sort characterisation of oxide layers on technical copper based on visible hyperspectral imaging
topic hyperspectral imaging
pushbroom imaging
copper oxide
oxide layer thickness
multivariate analysis
partial least square regression
prediction
reflectance
url https://www.impopen.com/download.php?code=I08_a10
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