SEM Azimuth Detection for Clear Magnetic Domain Imaging
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Solution Overview
Problem
In SEM observation, it is challenging to obtain a clear Type-I magnetic domain contrast image due to weaker contrast compared to edge or potential contrasts, and existing methods struggle to isolate magnetic domain contrast effectively, especially at low magnification, leading to difficulties in emphasizing magnetic domain features.
Innovation Solution
A charged particle beam device equipped with a detector capable of separately detecting secondary electrons in multiple azimuth angles and an image processing unit for shading correction and contrast adjustment, allowing for the synthesis of images from different emission azimuths to enhance magnetic domain contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If azimuth discrimination detection is performed using a dome-shaped grid electrode and shielding plate to observe magnetic domain contrast, then magnetic domain contrast can be detected, but shading contrast is superimposed and magnetic domain contrast cannot be selectively emphasized
Solution Approach 1:
The detector is divided into multiple detection units arranged in different azimuth directions. Each detection unit detects secondary electrons from a specific azimuth range, allowing separate measurement of magnetic domain contrast from different directions. This segmentation enables the system to acquire multiple images with different shading patterns that can be processed to eliminate shading effects.
Solution Approach 2:
The system changes the detection parameter by acquiring images at multiple azimuth angles. By varying the azimuth detection direction and combining multiple images through image processing, the shading contrast (which varies with azimuth) can be differentiated from the magnetic domain contrast (which is azimuth-independent), allowing selective emphasis of magnetic domain features.
2Measurement precision
If Type-I magnetic domain contrast observation is performed, then magnetic domain structure can be observed, but edge contrast and potential contrast are mixed making it difficult to emphasize magnetic domain contrast
Solution Approach 1:
The detector is segmented into multiple azimuth-specific detection units, each capturing secondary electrons from different emission directions. This spatial segmentation in azimuth space allows the system to separate magnetic domain contrast information from other contrast mechanisms through differential measurement and image processing.
Solution Approach 2:
The detection system varies the azimuth detection parameter to acquire multiple images. Since edge contrast and potential contrast have different azimuthal dependencies compared to magnetic domain contrast, changing the detection azimuth and processing the resulting image set allows selective extraction of magnetic domain contrast information.
3Measurement precision
If secondary electrons are selectively detected in a specific azimuth to observe magnetic domain contrast, then magnetic domain contrast can be obtained, but the contrast is weaker than edge and potential contrasts making clear observation difficult
Solution Approach 1:
The system merges signals from multiple detection units detecting secondary electrons from different azimuth directions. By combining the detected signals through appropriate signal processing, the magnetic domain contrast information is enhanced while suppressing other contrast mechanisms, effectively increasing the relative contrast intensity of magnetic domain features.
Solution Approach 2:
The system utilizes parameter changes in detection azimuth to differentiate and enhance magnetic domain contrast. By acquiring images at multiple azimuth angles and processing them to exploit the unique azimuthal characteristics of magnetic domain contrast, the effective contrast intensity is enhanced relative to background contrasts.
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 prevents shading contrast and enables the acquisition of clear, high-resolution magnetic domain contrast images with high throughput, effectively isolating magnetic domain features from other contrasts.
Implementation Method 1
an objective lens configured to focus charged particle beams on a sample
Implementation Method 2
an electric field generation unit that applies an accelerating electric field to secondary electrons generated from the sample
Implementation Method 3
a detector that is mounted on a charged particle beam source side with respect to the objective lens and is capable of separately detecting secondary electrons emitted in azimuth angle ranges of two or more different azimuths
Data Source
AI summary
A charged particle beam device which prevents an appearance of a shading contrast due to azimuth discrimination and obtains a clear magnetic domain contrast image with a high resolution and a high throughput. The charged particle beam device includes an electron beam source; a sample stage; an objective lens configured to focus electron beams on a sample; a detector that is mounted on a charged particle beam source side with respect to the objective lens and separately detects secondary electrons emitted in azimuth angle ranges of two or more different azimuths for the same observation region; an image processing and image management device including an image processing unit configured to perform synthesis after performing shading correction and contrast adjustment on an image obtained by detecting a first emission azimuth and an image obtained by detecting a second emission azimuth; an image database; and an image display unit.