Charged Particle Beam Device Signal Separation

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Solution Overview

Problem

In conventional electron microscopes, secondary electrons and backscattered electrons cannot be distinguished, leading to increased background noise and reduced sensitivity in analysis methods like Auger electron spectroscopy, which affects the quality of elemental analysis.

Innovation Solution

A charged particle beam device that includes a charged particle beam source, an analyzer, a bias voltage applying unit, and an analysis unit capable of applying different bias voltages or varying the kinetic energy of the primary charged particle beam to extract signal components of secondary electrons and backscattered electrons by obtaining and processing multiple spectra.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a total electron spectrum is measured to detect both secondary electrons and backscattered electrons, then all electron signals can be detected, but the background increases and sensitivity decreases

Engineering Contradiction:

Improveelectron signal detectionVSAvoidanalysis sensitivity

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments the total electron signal into two distinct components: secondary electron signal and backscattered electron signal. This is achieved by measuring electron spectra at different acceleration voltages, where secondary electrons exhibit voltage-independent kinetic energy while backscattered electrons show voltage-dependent kinetic energy. The segmentation allows separate analysis of each component, eliminating background interference and improving measurement precision.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If secondary electrons and backscattered electrons are not distinguished, then the measurement process is simple, but the analysis quality deteriorates due to increased background

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidanalysis quality

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the acceleration voltage parameter to distinguish between secondary electrons and backscattered electrons. By measuring spectra at multiple acceleration voltages and analyzing the kinetic energy distribution, the system can identify which electrons are secondary (voltage-independent) and which are backscattered (voltage-dependent). This parameter-based differentiation maintains operational simplicity while dramatically improving analysis quality.

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

Enables clear distinction and separation of secondary electron and backscattered electron signals, improving the quality of analysis and reducing background noise, thereby enhancing the sensitivity and accuracy of elemental analysis.

Implementation Method 1

a bias voltage applying unit that applies a bias voltage to the specimen

Methodology Applied

Scientific EffectBias voltage application: Electric Field

Implementation Method 2

an analyzer that analyzes and detects particles including secondary electrons and backscattered charged particles that are emitted from a specimen

Methodology Applied

Scientific EffectElectron energy spectrum analysis: Electron Beam

Implementation Method 3

an analysis unit that extracts a signal component of the secondary electrons based on a first spectrum obtained by detecting the particles with the analyzer in a state where a first bias voltage is applied to the specimen, and a second spectrum obtained by detecting the particles with the analyzer in a state where a second bias voltage different from the first bias voltage is applied to the specimen

Methodology Applied

Scientific EffectSpectrum processing:

Data Source

PatentUS11710615B2Charged particle beam device and analysis method

Publication Date: 2023.07.25 JEOL LTD

AI summary

A charged particle beam device includes: a charged particle beam source; an analyzer that analyzes and detects particles including secondary electrons and backscattered charged particles that are emitted from a specimen by irradiating the specimen with a primary charged particle beam emitted from the charged particle beam source; a bias voltage applying unit that applies a bias voltage to the specimen; and an analysis unit that extracts a signal component of the secondary electrons based on a first spectrum obtained by detecting the particles with the analyzer in a state where a first bias voltage is applied to the specimen, and a second spectrum obtained by detecting the particles with the analyzer in a state where a second bias voltage different from the first bias voltage is applied to the specimen.