Charged-particle microscopy occlusion detection

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Solution Overview

Problem

Charged-particle microscopes face challenges in analyzing samples with significant surface topography due to occlusion effects, which hinder the detection of emitted radiation, particularly X-rays, as traditional methods like embedding and polishing are cumbersome and time-consuming, and existing techniques fail to effectively mitigate line-of-sight occlusions.

Innovation Solution

The method involves using multiple detector configurations to detect different types of emitted radiation simultaneously, comparing images from various detector positions, and mathematically fusing these images to identify and quantify occlusion regions, thereby creating a composite reference image that mitigates occlusion effects by 'erasing' occluded areas, allowing for more efficient analysis of samples with surface relief.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional embedding and polishing methods are used to analyze samples with surface topography, then occlusion effects are reduced, but the process becomes cumbersome and time-consuming

Engineering Contradiction:
Improvedetection accuracyVSAvoidpreparation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces mechanical embedding and polishing processes with a computational image processing system. Multiple images taken from different detector configurations are mathematically fused to create a composite reference image that eliminates occlusion effects through algorithms rather than physical sample modification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a new dimension of analysis by capturing images from multiple detector configurations (different spatial positions and orientations) and fusing them computationally. This multi-dimensional approach allows occlusion in one view to be compensated by unoccluded views from other configurations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple detector configurations are used to detect emitted radiation, then occlusion regions can be identified and quantified, but the device complexity increases

Engineering Contradiction:
Improveocclusion detection accuracyVSAvoiddetector system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the detector system multi-functional by using the same detector in multiple configurations to perform both imaging and occlusion detection. The detector serves dual purposes: capturing radiation emission data and providing geometric information for occlusion identification through mathematical fusion of multiple configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If traditional single detector configuration is used, then the setup is simpler, but occlusion effects prevent accurate compositional analysis

Engineering Contradiction:
Improvedetector configurationVSAvoidcompositional analysis accuracy
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent merges multiple detector configuration images into a single composite reference image through mathematical fusion. This combining process integrates information from different viewing angles and detector positions to produce a comprehensive image that eliminates occlusion artifacts and preserves complete compositional information.

Inventive Principle:
Principle #5Merging (Combining)

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 identification and quantification of occlusion regions, reduces radiation damage to samples, and provides a more accurate analysis of samples with surface topography, improving the compositional analysis of mineralogical and other samples by eliminating occlusion issues and allowing for quicker data acquisition.

Implementation Method 1

Using a particle-optical column to direct at least one beam of particulate radiation onto the sample, thereby producing an interaction that causes emitted radiation to emanate from the sample

Methodology Applied
Scientific EffectCharged particle interaction:

Implementation Method 2

Using a first detector configuration C1 to detect a first portion of the emitted radiation and produce a first image I1 based thereupon

Methodology Applied
Scientific EffectRadiation detection:

Data Source

PatentEP2525386B1Charged-particle microscopy with occlusion detection
Publication Date: 2015.01.28 FEI CO
  • EP2525386B1 patent drawingFigure 1A
  • EP2525386B1 patent drawingFigure 1B
  • EP2525386B1 patent drawingFigure 2

AI summary

A method of examining a sample using a charged-particle microscope, comprising the following steps: - Mounting the sample on a sample holder; - Using a particle-optical column to direct at least one beam of particulate radiation onto the sample, thereby producing an interaction that causes emitted radiation to emanate from the sample; - Using a first detector configuration C1 to detect a first portion of the emitted radiation and produce a first image I1 based thereupon, which method comprises the following steps: - Using at least a second detector configuration C2 to detect a second portion of the emitted radiation and produce a second image I2 based thereupon, whereby C2 is different to C1, thus compiling a set SD = {C1, C2} of detector configurations and a set SI = {I1, I2} of corresponding images; - Using computer processing apparatus to automatically compare different members of SI and mathematically identify on the sample at least one occlusion region with an occluded line of sight relative to at least one member of SD. In a particular embodiment: - Plural members of SI are mathematically fused into a composite reference image IF; - At least one test image IT is selected from SI; - Said occlusion region is identified using a technique that comprises comparing IF to IT and identifying an area in IT in which at least one of the following is observed: ■ A reduced correlation between IT and IF; ■ A reduced intensity in IT relative to IF.