Charged Particle Beam Defect Detection via Dynamic Magnification Switching
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Solution Overview
Problem
Existing charged particle beam apparatuses face inefficiencies in high accuracy positioning and defect detection, particularly due to inaccurate image acquisition conditions and poor resolution at low magnification, leading to prolonged imaging and detection times.
Innovation Solution
The apparatus switches image acquisition conditions to include a reduced number of integrated image frames and updates the visual field central coordinate based on defect detection accuracy, employing a vector scanning method to optimize scanning conditions and improve defect detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of integrated image frames is increased to improve defect detection accuracy, then the detection precision is improved, but the processing time is prolonged
Solution Approach 1:
The patent segments the imaging process into multiple passes: first capturing a low-magnification overview image to identify the defect region, then capturing a high-magnification detailed image only of the suspected defect area. This segmentation allows the system to use fewer integrated frames overall while maintaining detection accuracy by concentrating frames on the critical region.
Solution Approach 2:
The patent introduces a two-stage magnification dimension to the imaging process. By switching from low magnification (for broad coverage) to high magnification (for detailed inspection), the system achieves accurate defect detection with fewer total frames integrated, as the high-magnification frames are concentrated on smaller, more relevant regions.
2Area of stationary object
If the imaging region is expanded to cover the entire defect area, then the coverage is improved, but the processing time is prolonged
Solution Approach 1:
The patent divides the imaging region into two stages: an initial large-area low-magnification region to locate defects, followed by a focused small-area high-magnification region for detailed inspection. This segmentation reduces the total processing time by avoiding the need to capture high-magnification images of the entire large area.
Solution Approach 2:
The patent performs preliminary low-magnification imaging to identify and locate defect candidates before proceeding to high-magnification imaging. This preliminary action allows the system to pre-select the region of interest, thereby reducing the imaging region for the time-consuming high-magnification capture phase.
3Area of stationary object
If low magnification imaging is used to capture the entire defect area, then the coverage is improved, but the resolution is insufficient for accurate defect detection
Solution Approach 1:
The patent implements dynamic magnification switching, transitioning from low magnification (for broad coverage) to high magnification (for detailed inspection). This dynamic adjustment allows the system to maintain both wide coverage and high resolution by adapting the magnification level to the inspection stage.
Solution Approach 2:
The patent adds a magnification dimension to the imaging process, using low magnification for initial coverage and high magnification for detailed defect analysis. This dimensional change enables the system to achieve both broad coverage and high resolution, as the high-magnification images are taken only after the region of interest is identified.
4Measurement precision
If multiple image frames are integrated to improve signal-to-noise ratio, then the detection accuracy is improved, but the number of frames required increases processing time
Solution Approach 1:
The patent segments the frame integration process by applying it differently to different magnification levels. Low-magnification frames are integrated to establish the overview and locate defects, while fewer high-magnification frames are integrated focused on the defect region. This segmented approach maintains adequate signal-to-noise ratio while reducing the total number of frames processed.
Solution Approach 2:
The patent uses magnification as an additional dimension to optimize frame integration. By capturing frames at different magnification levels and integrating them selectively, the system achieves good signal-to-noise ratio in the critical high-magnification defect region without requiring integration of a large total number of frames across the entire area.
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 significantly reduces the number of integrated image frames and imaging region, thereby shortening processing time and enhancing defect detection accuracy, leading to improved throughput and more precise defect classification.
Implementation Method 1
a charged particle beam apparatus which images a site appearing as a defect on a sample by using a charged particle beam
Data Source
AI summary
There is provided a charged particle beam apparatus which can quickly perform high accuracy positioning and defect detection. A process of acquiring a low magnification defect image for one defect candidate and a process of specifying a region appearing as a defect are performed by repeatedly performing a defect detection process maximum n-times and by using an integrated frame image of the low magnification defect image having at least one frame or the maximum n-number of frames for one defect candidate. As the low magnification defect image used in order to generate a difference image with a low magnification reference image for one defect candidate, the integrated frame image is used which is obtained by adding the frames of the low magnification defect image having at least one frame or the maximum n-number of frames.