In Situ Coating Thickness Measurement of Parylene Using a Capacitive Sensor

Seidenath M, Jäger D, Wilhelm J, Rauh H, März M (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Journal of Electronic Materials Springer Verlag (Germany) / Institute of Electrical and Electronics Engineers (IEEE)

Original Authors: Manuel Seidenath, Daniel Jäger, Jochen Wilhelm, Hubert Rauh, Martin Maerz

Book Volume: 7

Article Number: 11

Issue: 2

Journal Issue: 2

DOI: 10.3390/electronicmat7020011

Abstract

With parylene coatings, conventional layer thickness measurement methods such as gravimetry, reflectometry, and cross-sectional microscopy are performed post-process and do not allow real-time monitoring or control. This paper presents a novel in situ measurement method based on the capacitance change in interdigitated copper electrodes fabricated on a printed circuit board (PCB). As parylene deposits on this sensor, the effective permittivity above the electrodes increases from 𝜖r≈1 (vacuum) to 𝜖r=2.1–3.2 (parylene), causing a measurable capacitance change. Finite element simulations were performed to model the relationship between layer thickness and sensor capacitance. Experimental validation with parylene C and F-VT4 demonstrated good agreement between simulation and measurement. Four consecutive parylene C runs with 60 g raw material showed reproducible capacitance increases of 49–53 pF, corresponding to layer thicknesses of 20–25 µm, verified by cross-sectional microscopy. Two coating runs were performed with parylene F-VT4 with target layer thicknesses of 2.5 µm and 5 µm. They show particularly good agreement with the simulation. The proposed method enables real-time process monitoring and provides a foundation for closed-loop control of parylene CVD processes.

Authors with CRIS profile

Manuel Seidenath Lehrstuhl für Leistungselektronik (LEE) Hubert Rauh Lehrstuhl für Elektronische Bauelemente Martin März Lehrstuhl für Leistungselektronik (LEE)

Involved external institutions

Justus-Liebig-Universität Gießen DE Germany (DE)

How to cite

APA:

Seidenath, M., Jäger, D., Wilhelm, J., Rauh, H., & März, M. (2026). In Situ Coating Thickness Measurement of Parylene Using a Capacitive Sensor. Journal of Electronic Materials, 7(2). https://doi.org/10.3390/electronicmat7020011

MLA:

Seidenath, Manuel, et al. "In Situ Coating Thickness Measurement of Parylene Using a Capacitive Sensor." Journal of Electronic Materials 7.2 (2026).

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