Monochromatic Monitoring Spreadsheet
Monochromatic optical monitoring remains a powerful tool in optical coating production. Level monitoring specification of a monitoring wavelength(s) and a termination level of monitoring signal for each coating layer. The termination level of the monitoring signal (transmittance or reflectance) determines the instant (trigger point) at which layer deposition should be terminated. A sequence of monitoring wavelengths and corresponding termination levels forms a monitoring spreadsheet. This spreadsheet may also include other useful information, for example, signal amplitude, maxima and minima values of the monitoring signal during layer deposition. OptiLayer has a powerful tool for creating of monitoring spreadsheets. The tool is available through:
Results --> Monitor
The OptiLayer Monitoring Spreadsheet consists of ten columns:
OptiLayer proposes various algorithms for specification of monitoring spreadsheets.
Creating a good set of instructions for an optical monitoring system can be a tedious task. The OptiLayer Monitor option enables you to create a monitoring spreadsheet for your design. The OptiMonitor dialog allows you to automatically generate the sequence of monitoring wavelength (so called Monitoring Strategies ), specify witness chips in the case indirect monitoring and graphically emulates the theoretical response of the optical monitor system during the deposition process. The Monitoring strategies are:
Strategy 1 is based on the choice of the most sensitive wavelength of each layer
Strategy 2 is aimed at minimizing the cumulative effect of thickness errors
Strategy 3 aimed at minimizing the cumulative effect of thickness errors and takes into account additional requirements that are necessary in order to increase the robustness and reliability of real-time algorithms working with Optical Monitoring Systems
Strategies 4 and 5 are very advanced strategies taking into account many criteria with ability to weight different requirements and simultaneously to minimize the number of different monitoring wavelengths. See the details in our recent publication.
See the details in our publications:
- M. Trubetskov, T. Amotchkina, A. Tikhonravov, Automated construction of monochromatic monitoring strategies, Appl. Opt., Vol. 54, pp. 1900-1909 (2015)
- A. V. Tikhonravov and M. K. Trubetskov, "Elimination of cumulative effect of thickness errors in monochromatic monitoring of optical coating production: theory," Appl. Opt. 46, 2084-2090 (2007).
- A. V. Tikhonravov, M. K. Trubetskov, and T. V. Amotchkina, "Computational experiments on optical coating production using monochromatic monitoring strategy aimed at eliminating a cumulative effect of thickness errors," Appl. Opt. 46, 6936-6944 (2007).
- A. V. Tikhonravov, M. K. Trubetskov, and T. V. Amotchkina, "Statistical approach to choosing a strategy of monochromatic monitoring of optical coating production," Appl. Opt. 45, 7863-7870 (2006)