Detector Segmentation for Reflectometry Alignment Stability
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Solution Overview
Problem
Existing systems for reflectometry, ellipsometry, and polarimetry require frequent realignment due to small changes in the angle and plane of incidence caused by sample orientation changes, such as lateral shifts or rotations, which increases the need for adjustments and reduces measurement accuracy.
Innovation Solution
A system comprising a source of electromagnetic radiation, a focusing lens, a sample, and a detector with dimensions smaller than the reflected beam, where a collimating lens is used to intercept less than the entire expanding or collimated beam, minimizing changes in the angle and plane of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the detector intercepts the entire reflected beam, then the signal intensity is maximized, but any change in sample orientation causes significant changes in the angle and plane of incidence
Solution Approach 1:
The detector is designed to intercept only a portion (segment) of the reflected beam rather than the entire beam. This segmentation allows the system to maintain measurement precision by reducing sensitivity to orientation changes while still capturing sufficient signal intensity for accurate measurements.
2Measurement precision
If the detector size is increased to capture more beam, then measurement signal is improved, but the system becomes more sensitive to sample orientation changes
Solution Approach 1:
The detector intentionally captures only a partial portion of the reflected beam rather than attempting to capture the entire beam. This partial action approach provides an optimal balance between maintaining adequate measurement signal quality and reducing sensitivity to sample orientation changes, thereby improving adaptability.
3Measurement precision
If manual realignment procedures are performed frequently, then measurement accuracy is maintained, but time consumption and operational complexity increase
Solution Approach 1:
The system provides self-alignment functionality where the detector's partial beam interception geometry automatically compensates for sample orientation changes. This self-service mechanism eliminates the need for frequent manual realignment procedures, saving time while maintaining measurement accuracy through the inherent geometric compensation of the detection system.
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 configuration reduces the impact of sample orientation changes on the effective angle and plane of incidence detected, minimizing the need for realignment and maintaining measurement accuracy across small positional and rotational changes.
Implementation Method 1
a focusing lens; In use said source of beam of electromagnetic radiation is caused to direct a beam of electromagnetic radiation through said focusing lens such that the resulting focused beam reflects from said sample
Implementation Method 2
a collimating lens before said detector, which serves to provide collimated electromagnetic radiation thereinto
Implementation Method 3
the resulting focused beam reflects from said sample in an expanding beam manner
Data Source
AI summary
A system which automatically reduces change in effective angle and plane of incidence of a reflected focused beam of electromagnetic radiation entering a detector, via use of a detector with dimensions less than is the spatial spread of a reflected focused beam at a location distal to the location on said sample from which it is caused to reflect, preferably after passing through a collimating lens. The basis of operation is that the portion of a reflected focused beam intercepted by the detector changes with change in sample position and/or orientation.