Presentation + Paper
28 September 2021 Pre-production simulation of optical monitoring combining monochromatic and broadband monitoring strategies
Silvia Schwyn Thoeny, Daniel Schachtler, Stephan Waldner, Thomas Frei, Manuel Baertschi
Author Affiliations +
Abstract
Various types of optical monitoring systems are established in industry. They range from single wavelength, over monochromatic to broadband monitoring to calculate a monitoring signal, which allows to terminate each layer in a filter at the required thickness. State of the art monitoring systems offer the capability of monochromatic and broadband monitoring in a single device. With these technologies available, the question arises how to combine these monitoring strategies for a specific application in a way, which leads to accurate coating results with the least sensitivity to production errors and thus to the highest yield. To answer this question without the need to perform costly coating runs, we developed a software tool, which mimics all the monitoring features of Evatec’s GSM optical monitoring system. Additionally, the software is able to disturb the simulated ideal monitoring signal with errors such as detector noise, drifts, deviations in shutter delay times, etc. The values of these disturbances are specific to the deposition tool. They were determined based on the broadband spectra of actual coating runs. By starting a virtual coating run with defined disturbances, the thickness deviations expected with a selected strategy can be assessed and the development of thickness deviations during the run, i.e. error compensation and error accumulation can be simulated. Within the software, parameters for the termination of each layer can be varied individually and the effect on the coating result can be observed. In order to demonstrate the capability of this tool, a specific coating design was then selected. For this design various monitoring strategies were tested, broadband strategies with different wavelength ranges, monochromatic strategies varying wavelength assignment per layer but also mixed strategies of broadband and monochromatic monitoring. The most stable monitoring strategy resulting from these simulations was coated as well as some of the less promising candidates and their results were compared.
Conference Presentation
© (2021) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Silvia Schwyn Thoeny, Daniel Schachtler, Stephan Waldner, Thomas Frei, and Manuel Baertschi "Pre-production simulation of optical monitoring combining monochromatic and broadband monitoring strategies", Proc. SPIE 11872, Advances in Optical Thin Films VII, 118720O (28 September 2021); https://doi.org/10.1117/12.2597085
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KEYWORDS
Coating

Error analysis

Camera shutters

Optical simulations

Data processing

Global system for mobile communications

Neodymium

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