15 November 2011 Estimation of the convergence order of rigorous coupled-wave analysis for OCD metrology
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Proceedings Volume 8321, Seventh International Symposium on Precision Engineering Measurements and Instrumentation; 83211M (2011) https://doi.org/10.1117/12.904664
Event: Seventh International Symposium on Precision Engineering Measurements and Instrumentation, 2011, Yunnan, China
Abstract
In most cases of optical critical dimension (OCD) metrology, when applying rigorous coupled-wave analysis (RCWA) to optical modeling, a high order of Fourier harmonics is usually set up to guarantee the convergence of the final results. However, the total number of floating point operations grows dramatically as the truncation order increases. Therefore, it is critical to choose an appropriate order to obtain high computational efficiency without losing much accuracy in the meantime. In this paper, the convergence order associated with the structural and optical parameters has been estimated through simulation. The results indicate that the convergence order is linear with the period of the sample when fixing the other parameters, both for planar diffraction and conical diffraction. The illuminated wavelength also affects the convergence of a final result. With further investigations concentrated on the ratio of illuminated wavelength to period, it is discovered that the convergence order decreases with the growth of the ratio, and when the ratio is fixed, convergence order jumps slightly, especially in a specific range of wavelength. This characteristic could be applied to estimate the optimum convergence order of given samples to obtain high computational efficiency.
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Yuan Ma, Shiyuan Liu, Xiuguo Chen, Chuanwei Zhang, "Estimation of the convergence order of rigorous coupled-wave analysis for OCD metrology", Proc. SPIE 8321, Seventh International Symposium on Precision Engineering Measurements and Instrumentation, 83211M (15 November 2011); doi: 10.1117/12.904664; https://doi.org/10.1117/12.904664
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