Automatic Fourier Harmonic Order Determination for Diffraction Structures
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Solution Overview
Problem
Existing methods for determining the Fourier harmonic order in rigorous coupled wave analysis (RCWA) are inefficient, often requiring extensive computational resources and are unsuitable for geometries with high pitch ratios, and tend to produce erratic results due to poor prediction of simulation reliability.
Innovation Solution
A method that automatically determines the Fourier harmonic order based on pitches in multiple directions, material properties, and characteristics of periodic structures, allowing for efficient computation of spectral information without the need for extensive electromagnetic simulations, using a software-defined map that considers interrelationships between these factors and constrains wavelength dependence to a low-order polynomial function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to determine Fourier harmonic order in RCWA, then spectral information can be computed, but computational costs are high and the process is time-consuming
Solution Approach 1:
The patent applies preliminary action by performing an initial estimation of the Fourier harmonic order using a fast algorithm before executing the full RCWA computation. This preliminary determination provides a starting point that reduces the computational burden of subsequent iterations, thereby decreasing overall computational time while maintaining spectral information accuracy.
Solution Approach 2:
The patent employs a simplified, computationally inexpensive model to estimate the Fourier harmonic order initially. This lightweight approach uses minimal computational resources to generate a preliminary result that serves as a foundation for more accurate but computationally intensive RCWA calculations, effectively separating the estimation phase from the precision computation phase.
2Measurement precision
If traditional methods are used to determine Fourier harmonic order, then spectral information can be obtained, but the process requires extensive computational resources
Solution Approach 1:
The patent segments the Fourier harmonic order determination process into two distinct phases: an initial estimation phase using a fast, low-resource algorithm, and a refinement phase using full RCWA. This segmentation allows the computationally expensive RCWA to be applied only when necessary, significantly reducing overall computational resource consumption while preserving spectral information accuracy.
Solution Approach 2:
By performing preliminary estimation of the Fourier harmonic order using minimal computational resources, the patent avoids the need to execute resource-intensive RCWA calculations from scratch. This preliminary action establishes a baseline that reduces the computational burden of subsequent precision calculations, thereby conserving computational energy and resources.
3Measurement precision
If traditional methods are used for structures with high pitch ratios, then spectral information can be computed, but results are erratic and unreliable
Solution Approach 1:
The patent implements feedback by using the results of the initial Fourier harmonic order estimation to guide and adjust the subsequent RCWA computation. This feedback mechanism ensures that the RCWA calculation is properly configured for the specific structure characteristics, particularly for high pitch ratio structures, thereby improving the reliability and consistency of spectral information results.
Solution Approach 2:
The patent applies parameter changes by adjusting the Fourier harmonic order based on structure-specific parameters such as pitch ratios. By dynamically modifying the harmonic order parameters according to the actual structure characteristics rather than using fixed traditional methods, the patent achieves more reliable and consistent spectral information computation across different structure types.
Data Source
AI summary
Automatic determination of Fourier harmonic order for computation of spectral information for diffraction structures described. An embodiment of a method includes automatically determining a Fourier harmonic order for computation of spectral information for periodic structures, wherein the determination of the Fourier harmonic order is based at least in part on the pitches in each of multiple directions of the periodic structures, material properties of the periodic structures, and characteristics of the periodic structures in which the materials are contained; and computing the spectral information for the periodic structures based at least in part on the determined Fourier harmonic order.