Charged-particle microscopy electron detection deconvolution
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Solution Overview
Problem
Conventional charged-particle microscopes face challenges in accurately separating energy and number variations of electrons due to the statistical nature of electron emission, resulting in 'jumbled' image information, which hinders specific electron imaging.
Innovation Solution
The method involves recording multiple images of a sample to calculate average signal strength and variance per pixel, allowing the creation of separate maps representing energy and number variations, effectively deconvolving the electron image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electron detection methods are used in charged-particle microscopes, then the imaging process is simplified, but the ability to separate energy and number variations of electrons is lost, resulting in jumbled image information
Solution Approach 1:
The patent segments the electron image data into separate energy and number components by recording multiple images at different electron energies and performing statistical analysis. This segmentation allows the detection system to resolve the jumbled information into distinct compositional and topographical maps, improving measurement precision without requiring a fundamentally more complex detector hardware system.
Solution Approach 2:
The patent adds a temporal dimension by recording multiple images over time and using statistical analysis to separate the overlapping energy and number information. By treating the problem in terms of time-series data and variance analysis rather than single-frame images, the system can deconvolve the jumbled information using mathematical relationships between mean and variance across multiple measurements.
2Measurement precision
If multiple images are recorded to calculate average signal strength and variance, then energy and number variations can be separated, but the imaging time increases
Solution Approach 1:
The patent uses periodic action by recording multiple images in a systematic sequence and applying statistical analysis to extract energy and number variations. The periodic recording of images allows the calculation of mean and variance values that separate compositional from topographical information, achieving precise separation while managing imaging time through efficient data acquisition protocols.
3Measurement precision
If X-ray spectroscopy is used to obtain compositional information, then accurate material identification is achieved, but the system complexity and cost increase
Solution Approach 1:
The patent creates a copy of compositional information by using electron energy and number variations as an alternative to X-ray spectroscopy. By analyzing the statistical properties of electron signals, the system generates compositional maps that replicate the information normally obtained from X-ray spectroscopy, but through a simpler electron-based detection mechanism that avoids the complexity and cost of X-ray detection systems.
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 enables the separation of compositional and topographical information, providing clearer images without the need for X-ray spectroscopy, and can be implemented using solid-state detectors for improved accuracy and cost-effectiveness.
Implementation Method 1
a beam of input charged particles is directed onto a sample using a so-called 'particle-optical column'
Implementation Method 2
When a charged-particle beam impinges on a sample, it generally interacts with the sample in a manner that causes different types of output radiation to emanate from the sample
Implementation Method 3
Electrons may, for example, be detected using a photo-multiplier tube (PMT) in conjunction with a scintillator
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A method of investigating a flux of output electrons emanating from a sample in a charged-particle microscope, which flux is produced in response to irradiation of the sample by a beam of input charged particles, the method comprising the following steps: - Using a detector to intercept at least a portion of the flux so as to produce a set {Ij} of pixeled images Ij of at least part of the sample, whereby the cardinality of the set {Ij} is M >1. - For each pixel pi in each image Ij, determining the accumulated signal strength Sij, thus producing an associated set of signal strengths {Sij}. - Using the set {Sij} to calculate the following values: ▪ An average signal strength S per pixel position i; ▪ A variance σ2S in S per pixel position i. - Using these values S and σ2S to at least one map of said part of the sample, selected from the group comprising: ▪ A first map, representing variation in energy of detected electrons as a function of position. ▪ A second map, representing variation in number of detected electrons as a function of position. The set [Ij} may be produced in different ways, such as: - By iteratively repeating a procedure whereby an entire nth image In is captured before proceeding to capture an entire (n+1)th image In+1; or - By iteratively repeating a procedure whereby, at an nth pixel position, a plurality M of different detector samples is collected before proceeding to an (n+1)th pixel position.