{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:16:16Z","timestamp":1760145376188,"version":"build-2065373602"},"reference-count":48,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2024,7,19]],"date-time":"2024-07-19T00:00:00Z","timestamp":1721347200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In the manufacturing process of electrical devices, ensuring the cleanliness of technical surfaces, such as direct bonded copper substrates, is crucial. An in-line monitoring system for quality checking must provide sufficiently resolved lateral data in a short time. UV hyperspectral imaging is a promising in-line method for rapid, contactless, and large-scale detection of contamination; thus, UV hyperspectral imaging (225\u2013400 nm) was utilized to characterize the cleanliness of direct bonded copper in a non-destructive way. In total, 11 levels of cleanliness were prepared, and a total of 44 samples were measured to develop multivariate models for characterizing and predicting the cleanliness levels. The setup included a pushbroom imager, a deuterium lamp, and a conveyor belt for laterally resolved measurements of copper surfaces. A principal component analysis (PCA) model effectively differentiated among the sample types based on the first two principal components with approximately 100.0% explained variance. A partial least squares regression (PLS-R) model to determine the optimal sonication time showed reliable performance, with R2cv = 0.928 and RMSECV = 0.849. This model was able to predict the cleanliness of each pixel in a testing sample set, exemplifying a step in the manufacturing process of direct bonded copper substrates. Combined with multivariate data modeling, the in-line UV prototype system demonstrates a significant potential for further advancement towards its application in real-world, large-scale processes.<\/jats:p>","DOI":"10.3390\/s24144680","type":"journal-article","created":{"date-parts":[[2024,7,19]],"date-time":"2024-07-19T09:14:53Z","timestamp":1721380493000},"page":"4680","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Rapid Detection of Cleanliness on Direct Bonded Copper Substrate by Using UV Hyperspectral Imaging"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9459-0640","authenticated-orcid":false,"given":"Mona","family":"Knoblich","sequence":"first","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"},{"name":"Institute of Physical and Theoretical Chemistry, Eberhard Karls University T\u00fcbingen, Auf der Morgenstelle 18, 72076 T\u00fcbingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6713-5669","authenticated-orcid":false,"given":"Mohammad","family":"Al Ktash","sequence":"additional","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"},{"name":"Institute of Physical and Theoretical Chemistry, Eberhard Karls University T\u00fcbingen, Auf der Morgenstelle 18, 72076 T\u00fcbingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6554-6600","authenticated-orcid":false,"given":"Frank","family":"Wackenhut","sequence":"additional","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8622-917X","authenticated-orcid":false,"given":"Tim","family":"Englert","sequence":"additional","affiliation":[{"name":"Robert Bosch GmbH, Automotive Electronics, T\u00fcbingerstra\u00dfe 123, 72762 Reutlingen, Germany"},{"name":"Center of Physics, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jan","family":"Stiedl","sequence":"additional","affiliation":[{"name":"Robert Bosch GmbH, Automotive Electronics, T\u00fcbingerstra\u00dfe 123, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hilmar","family":"Wittel","sequence":"additional","affiliation":[{"name":"Center of Physics, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simon","family":"Green","sequence":"additional","affiliation":[{"name":"Robert Bosch GmbH, Automotive Electronics, T\u00fcbingerstra\u00dfe 123, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7777-2306","authenticated-orcid":false,"given":"Timo","family":"Jacob","sequence":"additional","affiliation":[{"name":"Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1357-8453","authenticated-orcid":false,"given":"Barbara","family":"Boldrini","sequence":"additional","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0492-0544","authenticated-orcid":false,"given":"Edwin","family":"Ostertag","sequence":"additional","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3577-2903","authenticated-orcid":false,"given":"Karsten","family":"Rebner","sequence":"additional","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5537-1448","authenticated-orcid":false,"given":"Marc","family":"Brecht","sequence":"additional","affiliation":[{"name":"Center of Process Analysis and Technology (PA&T), School of Life Sciences, Reutlingen University, Alteburgstra\u00dfe 150, 72762 Reutlingen, Germany"},{"name":"Institute of Physical and Theoretical Chemistry, Eberhard Karls University T\u00fcbingen, Auf der Morgenstelle 18, 72076 T\u00fcbingen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,7,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Tomotoshi, D., and Kawasaki, H. 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