X-ray Diffraction Line Roughness Measurement
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Solution Overview
Problem
Current methods for measuring line roughness in microelectronic and photonic elements, such as scanning electron microscopes and atomic force microscopes, lack the necessary resolution and efficiency, requiring extensive image taking and processing time, while X-ray scattering techniques rely on computational models and multiple iterations.
Innovation Solution
A method involving the acquisition of a single diffraction image of X-rays scattered at small angles, calculating power spectral density, and determining characteristic parameters to measure line width roughness with high resolution and reduced processing time, specifically using the power spectral density to analyze the variation in line width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning electron microscope is used to measure line roughness, then measurement capability is provided, but resolution is limited to nanometer scale and measurement time is excessive
Solution Approach 1:
The patent replaces the mechanical scanning electron microscope system with an X-ray diffraction system. Instead of using electron beams and mechanical scanning, the invention uses X-ray diffraction patterns to measure line roughness, achieving both higher resolution (0.1 nm) and dramatically reduced measurement time through direct mathematical extraction from diffraction data
Solution Approach 2:
The patent transitions from real-space imaging (2D images requiring extensive processing) to reciprocal space analysis (diffraction patterns). By measuring in the Fourier domain rather than real space, the invention enables direct calculation of roughness parameters without time-consuming image acquisition and processing steps
2Measurement precision
If atomic force microscope is used to measure line roughness, then measurement capability is provided, but image acquisition time is even longer and resolution is limited to nanometer scale
Solution Approach 1:
The patent replaces the mechanical atomic force microscope system with an X-ray diffraction system. Instead of using physical probes and mechanical scanning, the invention uses X-ray diffraction patterns to measure line roughness, achieving both higher resolution (0.1 nm) and dramatically reduced measurement time through direct mathematical extraction from diffraction data
3Measurement precision
If small-angle X-ray scattering with computational models is used, then measurement capability is provided, but processing time is excessive due to multiple iterations
Solution Approach 1:
The patent extracts the essential roughness information directly from the diffraction pattern intensities without requiring full 3D structural modeling. By focusing only on the intensity variations in reciprocal space and applying direct mathematical transformations, the invention eliminates time-consuming iterative modeling while preserving measurement accuracy
Solution Approach 2:
The patent uses a simplified mathematical model that directly relates diffraction intensities to roughness parameters through power spectral density analysis. This simplified 'copy' of the full modeling approach provides accurate roughness measurements without requiring the computationally intensive iterative processes of complete structural refinement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves a resolution of 0.1 nm with significantly reduced time compared to existing methods, providing a direct and precise measurement of line width roughness without the need for three-dimensional modeling or extensive iterations.
Implementation Method 1
acquisition of at least one diffraction image in the reciprocal space of the network of lines obtained by collecting X-rays scattered at small angles
Data Source
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AI summary
Method for measuring the line width roughness of a grating of p lines of a sample, p being greater than or equal to 2, said lines having a length l, comprising: a) the acquisition of at least one diffraction image by small-angle X-ray transmission diffraction using an X-ray beam covering p lines of said grating, b) measurement, on the diffraction image, of the intensities along the direction qy, in a cutting plane passing through qx = 0, c) division of said intensities by n and by l, d) plotting of the power spectral density as a function of qy, e) determination from the power spectral density of characteristic parameters of the line width roughness, forming the measure of the line width roughness.