Plasmonic Antenna Misalignment Measurement via Absorption
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Solution Overview
Problem
Current methods for measuring misalignment between etching zones, particularly in electron beam lithography, are slow and complex, often requiring scanning electron microscopes and being unsuitable for small dimensions and multi-beam machines.
Innovation Solution
A method using plasmonic antennas with polarized radiation sources and reflected radiation intensity sensors to measure misalignment by detecting changes in absorption rates, allowing for quick and precise determination of misalignment without the need for complex equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods using scanning electron microscopes are used to measure misalignment, then measurement precision can be achieved, but the measurement process becomes slow and complicated
Solution Approach 1:
The patent replaces the mechanical scanning electron microscope system with an optical measurement system using polarized radiation and photodetectors. This substitution eliminates the need for complex mechanical scanning while maintaining measurement precision through optical interference patterns, thereby significantly reducing measurement time and simplifying the measurement process.
Solution Approach 2:
The invention creates an optical copy or representation of the misalignment through interference patterns generated by polarized radiation. Instead of directly scanning and imaging the physical structures, the system captures misalignment information through optical field interactions, enabling rapid non-contact measurement without the time-consuming mechanical scanning process.
2Measurement precision
If known patterns are used for misalignment measurement, then measurement can be performed, but the patterns are too large to be produced within a single field of multi-beam machines
Solution Approach 1:
The patent fundamentally changes the measurement approach from using large physical patterns to using optical field parameters (polarization states and interference patterns). This parameter transformation allows misalignment measurement without requiring large-area physical structures, making it compatible with the small field sizes of multi-beam lithography machines while maintaining measurement precision.
Solution Approach 2:
The invention transitions from spatial dimension (large physical patterns) to optical field dimension (polarization and interference characteristics). By measuring misalignment through optical field interactions rather than physical pattern dimensions, the system eliminates the area constraint imposed by multi-beam machine field sizes.
3Ease of operation
If simple measurement methods are used, then ease of operation is improved, but measurement precision and resolution are insufficient
Solution Approach 1:
The patent applies local quality by using polarized radiation with specific polarization states that interact differently with the measurement target based on local misalignment characteristics. This allows the system to extract precise misalignment information through localized optical field interactions, achieving high measurement resolution while maintaining operational simplicity through automated photodetector readings.
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
Enables rapid and simple measurement of misalignment between etching zones with high resolution, suitable for smaller dimensions and multi-beam machines, reducing the complexity and time associated with traditional methods.
Implementation Method 1
the absorption rate of this plasmonic antenna and a predicted value for this absorption rate in the absence of misalignment, it is possible to determine the amplitude of the misalignment between these two etching zones
Implementation Method 2
measuring means for measuring an absorption rate of this plasmonic antenna
Implementation Method 3
A method using plasmonic antennas with polarized radiation sources and reflected radiation intensity sensors to measure misalignment by detecting changes in absorption rates
Data Source
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AI summary
This method for measuring the misalignment between a first and a second etching zone comprises: - the fabrication (112) of a plasmonic antenna comprising a first and a second distinct elements which each delimit, on a respective side, a hollow, all the elements of the plasmonic antenna located on a first side of a separation plane being entirely made inside the first zone and all the elements of the plasmonic antenna located on the second side of the separation plane being entirely made inside the second zone, - after the fabrication of the plasmonic antenna, the method comprises: • the measurement (114) of the absorption rate of the plasmonic antenna, and • the determination (128, 130) of the amplitude of the misalignment between the first and second zones from the measured absorption rate and a predicted value for this absorption rate in the absence of misalignment.