Charged Particle Microscopy Phase Mapping from Sparse EDS Spectra
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Solution Overview
Problem
Current charged particle microscopy methods, such as EDS, are slow in determining chemical compositions of samples due to the time-consuming process of accumulating x-ray spectra at discrete analysis points.
Innovation Solution
A method that uses spectral information from detected emissions to rapidly and accurately assign phases to sample locations by combining measured data with estimated data, utilizing a machine learning estimator to predict dense spectra from sparse ones, and dividing the sample area into segments for improved phase estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional EDS spectroscopy is used to accumulate x-ray spectra at discrete analysis points, then accurate phase determination is achieved, but the analysis speed is slow
Solution Approach 1:
The patent applies preliminary action by performing a first scan of the sample to collect spectral information at multiple locations before conducting detailed phase analysis. This preliminary scanning phase allows the system to gather data that can be used to predict phases at subsequent locations, thereby accelerating the overall analysis speed while maintaining accuracy.
Solution Approach 2:
The patent uses copying by creating a data structure that stores spectral information from previously scanned locations and uses this stored data to predict phases at new locations. Instead of performing complete spectral analysis at every point, the system copies and utilizes patterns from previously analyzed regions to estimate phases at unanalyzed locations, significantly reducing analysis time.
2Measurement precision
If the electron beam dwells at each analysis point to accumulate sufficient x-ray counts, then accurate spectral data is obtained, but the total analysis time increases considerably
Solution Approach 1:
The patent applies partial action by collecting spectral information at a reduced number of discrete locations during the preliminary scan, rather than performing complete spectral accumulation at every possible analysis point. This partial data collection is sufficient to establish phase patterns that can then be extrapolated to cover the entire sample area, reducing total analysis time while maintaining data quality.
Solution Approach 2:
The system performs preliminary scanning to gather spectral data at selected locations before the main analysis phase. This preliminary action allows the system to build a phase map using fewer dwell times per location, and then use this map to guide or replace subsequent detailed measurements, thereby reducing the total time required while preserving spectral data quality where needed.
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 significantly accelerates the EDS mapping process, allowing for high-quality phase determination with an order of magnitude increase in speed and improved data acquisition efficiency, even with sparse spectral data.
Implementation Method 1
Irradiation of a specimen by a scanning electron beam precipitates emanation of 'auxiliary' radiation from the specimen, in the form of secondary electrons, backscattered electrons, X-rays and cathodoluminescence (infrared, visible and/or ultraviolet photons).
Implementation Method 2
typically, in a SEM backscattered electrons are detected by a solid state detector in which each backscattered electron is amplified as it creates many electron-hole pairs in a semiconductor detector
Implementation Method 3
In a process called 'energy dispersive x-ray spectroscopy' (also referred to as 'EDS' or 'EDX'), the energies of x-rays coming from the sample in response to the electron beam are measured and plotted in a histogram to form a material specific spectrum.
Data Source
AI summary
The invention relates to a method of examining a sample using a charged particle microscope, comprising the steps of providing a charged particle beam, as well as a sample; scanning said charged particle beam over said sample at a plurality of sample locations; and detecting, using a first detector, emissions of a first type from the sample in response to the beam scanned over the plurality of sample locations. Spectral information of detected emissions of the first type is used to assign a plurality of mutually different phases to said sample at said plurality of sample locations. Information relating to at least one previously assigned phase and its respective sample location is used for establishing an estimated phase for at least one other of the plurality of sample locations. Said estimated phase is assigned to said other sample location. A control unit is used to provide a data representation of said sample containing at least information on said plurality of sample locations and said phases.