Scanning Electron Microscope Electron Sorting and Deflection
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Solution Overview
Problem
Scanning electron microscopes produce different electron images of the same sample due to variations in electron detector placement and detected electron energy and emission angle, lacking control over emission angle selection.
Innovation Solution
A scanning charged particle microscope with a sorting portion for selecting electrons by emission angle, a deflector for deflecting electrons based on energy, and a detection portion for imaging electrons with specific energy and angle, using a static electric field to sort and detect electrons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconductor detector is installed at different positions for each instrument, then the detector can detect electrons from the sample, but the detected electron energy and emission angle vary between instruments, leading to inconsistent images
Solution Approach 1:
The patent applies parameter changes by introducing controllable variables (electric field strength, detector position) that allow systematic adjustment of detection conditions. The electric field parameters are modified to deflect electrons with different energies and emission angles to the detector, enabling consistent detection across different instruments while maintaining the ability to adapt to various detection requirements.
2Measurement precision
If the electron beam is scanned to obtain composition and morphology information, then a scanned electron image is obtained, but individual different SEM instruments produce different images of the same sample
Solution Approach 1:
The patent introduces an intermediary mechanism - the electric field deflection system - that acts as a mediator between the electron source and detector. This intermediary controls the electron trajectories through adjustable electric fields, compensating for instrument-to-instrument variations and ensuring that electrons with specific energies and emission angles are consistently directed to the detector regardless of the specific instrument used.
3Ease of operation
If electrons are detected without selection by emission angle and energy, then detection is simplified, but control over detected electron characteristics is lost
Solution Approach 1:
The patent applies dynamics by making the detection system adjustable and adaptable rather than fixed. The electric field strength and detector position can be dynamically modified to select different electron energies and emission angles. This dynamic control allows the system to maintain operational simplicity while achieving precise electron selection, as the adjustments are made through controlled parameter changes rather than complex mechanical modifications.
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 selective detection and imaging of electrons by energy and angle, providing consistent and controlled electron images, allowing for emphasis on sample composition or morphology.
Implementation Method 1
the deflector has electrodes for producing a static electric field in the path of electrons sorted out by the sorting portion. The deflecting field is produced by the static electric field.
Implementation Method 2
an objective lens for bringing the charged particle beam emitted from the source into focus at a sample
Implementation Method 3
a detection portion for detecting the deflected electrons
Data Source
Figure 1
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AI summary
A scanning charged particle microscope is offered which can selectively detect and image electrons. The scanning charged particle microscope (100) has: a source (1) of a charged particle beam (E1); an objective lens (6) for bringing the charged particle beam (E1) emitted from the source (1) into focus at a sample (S); a scanning deflector (4) for scanning the focused charged particle beam (E1) over the sample (S); a sorting portion (10) for sorting out electrons emitted at given emission angles from electrons released from the sample (S) in response to irradiation of the sample (S) by the charged particle beam (E1); an electron deflector (20) for producing a deflecting field to deflect the electrons (E2) sorted out according to their energy; a detection portion (30) for detecting the electrons (E2) deflected by the electron deflector (20); and an image creating portion (44) for creating an image, based on the results of the detection performed by the detection portion (30).