Ellipsometer Beam Characterization via Spatial Ray Segmentation
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Solution Overview
Problem
In ellipsometer systems, the increasing complexity due to decreasing sample size and the need for higher accuracy in measurement data leads to non-trivial multi-beam-ray effects, causing variations in sample characterization results, which require more detailed calibration and analysis to account for different optical paths and effects like reflection, refraction, and polarization changes.
Innovation Solution
The method involves subdividing the measurement beam into spatially distributed beam rays, providing parameterized mathematical models for each ray, and performing a data regression calibration to account for multi-beam-ray effects, allowing for accurate determination of sample parameters that minimize deviations from true values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single beam model is used for sample characterization, then the system is simpler to operate, but measurement precision deteriorates due to unaccounted multi-beam-ray effects
Solution Approach 1:
The invention segments the measurement beam into multiple spatially distributed beam rays, each treated as an independent source. This segmentation allows the system to account for different optical paths and multi-beam-ray effects while maintaining a manageable computational framework through parameterized mathematical models for each ray.
2Measurement precision
If beam size is decreased to improve sample characterization, then measurement precision improves, but device complexity increases due to significant multi-beam-ray effects
Solution Approach 1:
The invention changes the parameters of the mathematical models to account for multi-beam-ray effects. By using parameterized models that incorporate reflection, refraction, coordinate system changes, AOI, POI, and polarization state changes for each beam ray, the system accurately characterizes samples while managing complexity through systematic parameter optimization.
3Measurement precision
If detailed calibration procedures are implemented to account for multi-beam-ray effects, then measurement precision improves, but loss of time increases due to complex data analysis
Solution Approach 1:
The invention performs preliminary actions by establishing parameterized mathematical models for each beam ray before actual measurements. The systematic calibration procedure using known samples pre-determines the relationship between beam parameters and sample characteristics, reducing the time required for analysis during actual measurements.
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 approach improves the accuracy of sample characterization by treating each beam ray as an independent source, reducing errors from multi-beam-ray effects and providing more precise sample parameter values compared to single-ray systems.
Implementation Method 1
Various parts of a sample investigating beam can produce different results because of different reflection, refraction, coordinate System changes, (AOI), (POI) and general polarization state changes
Implementation Method 2
Various parts of a sample investigating beam can produce different results because of different reflection, refraction, coordinate System changes, (AOI), (POI) and general polarization state changes
Implementation Method 3
causing the resulting polarized electromagnetic beam to interact with a calibration sample... and then enter a polarization state detector
Data Source
AI summary
An approach to characterizing beams of electromagnetic radiation such as are applied in ellipsometer and the like systems, involving considering the beam to be comprised of a number of spatially distributed beam rays, each of which is represented mathematically as an effectively independent source.