Elemental Map Correction for Detector Sensitivity Variations

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Solution Overview

Problem

Surface analyzers, such as Auger electron microscopes, face challenges in generating elemental maps due to positional dependence of detector sensitivity, leading to variations in brightness, especially at low magnification, which affects the accuracy of elemental distribution analysis.

Innovation Solution

A method and apparatus for generating elemental maps by scanning a specimen with a primary beam, separating signals with a spectrometer, and detecting them with a multi-channel detector, where correction channel images from a standard specimen are used to generate correction information to normalize pixel brightness values in analysis channel images, reducing positional sensitivity variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a multi-channel detector is used to acquire elemental maps by scanning the specimen surface, then the ability to detect electrons with different energies independently is improved, but positional dependence of detector sensitivity causes variation in brightness on the elemental map

Engineering Contradiction:
Improveenergy detection precisionVSAvoidbrightness uniformity
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by acquiring correction channel images from a standard specimen before analyzing the actual specimen. These correction images capture the positional sensitivity variations of the detector, which are then used to correct the analysis channel images. This pre-correction approach eliminates brightness variations caused by detector position dependence while preserving the multi-channel energy detection capability.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If correction channel images are acquired from a standard specimen to correct positional sensitivity variations, then brightness uniformity is improved, but the complexity of the measurement process increases

Engineering Contradiction:
Improvebrightness uniformityVSAvoidmeasurement process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses copying by creating correction channel images that replicate the detector's sensitivity characteristics from a standard specimen. These correction images serve as reference copies that can be applied to correct multiple analysis images, reducing the need for repeated complex calibration procedures and simplifying the overall measurement process.

Inventive Principle:
Principle #26Copying

3Measurement precision

If correction coefficients are calculated to normalize pixel brightness values, then the accuracy of elemental distribution analysis is improved, but additional processing time and computational resources are required

Engineering Contradiction:
Improveelemental distribution accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies parameter changes by calculating correction coefficients that transform the brightness values of pixels in analysis channel images. These coefficients are derived from correction channel images and are used to normalize the brightness values across different positions. This parameter transformation approach efficiently corrects positional sensitivity variations with minimal additional processing time.

Inventive Principle:
Principle #35Parameter changes

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 results in elemental maps with reduced brightness variations, improving the accuracy and consistency of elemental distribution analysis by correcting for detector sensitivity positional dependence, even at low magnification.

Implementation Method 1

acquires an elemental map by scanning a surface of a specimen with a primary beam

Methodology Applied
Scientific EffectElectron beam irradiation: Electron Beam

Implementation Method 2

detecting Auger electrons emitted from each measurement point

Methodology Applied
Scientific EffectAuger electron emission: Auger Effect

Implementation Method 3

separating signals emitted from the specimen with a spectrometer

Methodology Applied
Scientific EffectEnergy separation:

Implementation Method 4

detecting the separated signals with a detector having a plurality of channels capable of detecting the signals having energies that differ from one another

Methodology Applied
Scientific EffectElectron detection:

Data Source

PatentEP3633361B1Method of generating elemental map and surface analyzer
Publication Date: 2022.03.23 JEOL LTD
  • EP3633361B1 patent drawingFigure 1
  • EP3633361B1 patent drawingFigure 2
  • EP3633361B1 patent drawingFigure 3

AI summary

A method of generating an elemental map includes : acquiring a plurality of correction channel images by scanning a surface of a standard specimen having a uniform elemental concentration with a primary beam and generating a correction channel image for each channel; generating correction information for each pixel of each correction channel image among the plurality of correction channel images based on a brightness value of the pixel; acquiring a plurality of analysis channel images by scanning a surface of a specimen to be analyzed with the primary beam and generating an analysis channel image for each channel; correcting brightness values of pixels constituting an analysis channel image among the plurality of analysis channel images based on the correction information; and generating an elemental map of the specimen to be analyzed based on the plurality of analysis channel images having pixels with corrected brightness values.