A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing
The requirement for alternatives in roll-to-roll (R2R) processing to expand thin film inspection in wider substrates at lower costs and reduced dimensions, and the need to enable newer control feedback options for these types of processes, represents an opportunity to explore the applicability of ne...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-06-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/11/5326 |
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| author | Néstor Eduardo Sánchez-Arriaga Divya Tiwari Windo Hutabarat Adrian Leyland Ashutosh Tiwari |
| author_facet | Néstor Eduardo Sánchez-Arriaga Divya Tiwari Windo Hutabarat Adrian Leyland Ashutosh Tiwari |
| author_sort | Néstor Eduardo Sánchez-Arriaga |
| collection | DOAJ |
| description | The requirement for alternatives in roll-to-roll (R2R) processing to expand thin film inspection in wider substrates at lower costs and reduced dimensions, and the need to enable newer control feedback options for these types of processes, represents an opportunity to explore the applicability of newer reduced-size spectrometers sensors. This paper presents the hardware and software development of a novel low-cost spectroscopic reflectance system using two state-of-the-art sensors for thin film thickness measurements. The parameters to enable the thin film measurements using the proposed system are the light intensity for two LEDs, the microprocessor integration time for both sensors and the distance from the thin film standard to the device light channel slit for reflectance calculations. The proposed system can deliver better-fit errors compared with a HAL/DEUT light source using two methods: curve fitting and interference interval. By enabling the curve fitting method, the lowest root mean squared error (RMSE) obtained for the best combination of components was 0.022 and the lowest normalised mean squared error (MSE) was 0.054. The interference interval method showed an error of 0.09 when comparing the measured with the expected modelled value. The proof of concept in this research work enables the expansion of multi-sensor arrays for thin film thickness measurements and the potential application in moving environments. |
| first_indexed | 2024-03-11T02:56:18Z |
| format | Article |
| id | doaj.art-0499ae06a6754f2e8a74b9952cec23ad |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-11T02:56:18Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-0499ae06a6754f2e8a74b9952cec23ad2023-11-18T08:35:39ZengMDPI AGSensors1424-82202023-06-012311532610.3390/s23115326A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and TestingNéstor Eduardo Sánchez-Arriaga0Divya Tiwari1Windo Hutabarat2Adrian Leyland3Ashutosh Tiwari4Amy Johnson Building, Department of Automatic Control and Systems Engineering, University of Sheffield, Portobello St., Sheffield S1 3JD, UKAmy Johnson Building, Department of Automatic Control and Systems Engineering, University of Sheffield, Portobello St., Sheffield S1 3JD, UKAmy Johnson Building, Department of Automatic Control and Systems Engineering, University of Sheffield, Portobello St., Sheffield S1 3JD, UKSir Robert Hadfield Building, Department of Materials Science and Engineering, University of Sheffield, Mappin St., Sheffield S1 3JD, UKAmy Johnson Building, Department of Automatic Control and Systems Engineering, University of Sheffield, Portobello St., Sheffield S1 3JD, UKThe requirement for alternatives in roll-to-roll (R2R) processing to expand thin film inspection in wider substrates at lower costs and reduced dimensions, and the need to enable newer control feedback options for these types of processes, represents an opportunity to explore the applicability of newer reduced-size spectrometers sensors. This paper presents the hardware and software development of a novel low-cost spectroscopic reflectance system using two state-of-the-art sensors for thin film thickness measurements. The parameters to enable the thin film measurements using the proposed system are the light intensity for two LEDs, the microprocessor integration time for both sensors and the distance from the thin film standard to the device light channel slit for reflectance calculations. The proposed system can deliver better-fit errors compared with a HAL/DEUT light source using two methods: curve fitting and interference interval. By enabling the curve fitting method, the lowest root mean squared error (RMSE) obtained for the best combination of components was 0.022 and the lowest normalised mean squared error (MSE) was 0.054. The interference interval method showed an error of 0.09 when comparing the measured with the expected modelled value. The proof of concept in this research work enables the expansion of multi-sensor arrays for thin film thickness measurements and the potential application in moving environments.https://www.mdpi.com/1424-8220/23/11/5326thin filmthickness measurementsreflectometrysensormicroprocessorPython |
| spellingShingle | Néstor Eduardo Sánchez-Arriaga Divya Tiwari Windo Hutabarat Adrian Leyland Ashutosh Tiwari A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing Sensors thin film thickness measurements reflectometry sensor microprocessor Python |
| title | A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing |
| title_full | A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing |
| title_fullStr | A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing |
| title_full_unstemmed | A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing |
| title_short | A Spectroscopic Reflectance-Based Low-Cost Thickness Measurement System for Thin Films: Development and Testing |
| title_sort | spectroscopic reflectance based low cost thickness measurement system for thin films development and testing |
| topic | thin film thickness measurements reflectometry sensor microprocessor Python |
| url | https://www.mdpi.com/1424-8220/23/11/5326 |
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