Multi-Beam Charged Particle Imaging Aperture Plate Zone Selection
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Solution Overview
Problem
Conventional multi-beam charged particle imaging apparatus face challenges in flexible beam current adjustment and aberration control due to high Coulomb interactions at beam crossovers, leading to image blur and reduced brightness.
Innovation Solution
The apparatus features an aperture plate with multiple zones having different aperture patterns and sizes, allowing for adjustable beam current through a selector device downstream, which selects and directs specific beam arrays to the specimen, avoiding beam crossovers and enabling both multi-beam and single-beam modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If beam crossovers are used in conventional multi-beam charged particle imaging apparatus, then beam current can be adjusted, but image blur occurs and image brightness is reduced due to high Coulomb interactions
Solution Approach 1:
The aperture plate is divided into multiple zones with different aperture patterns and sizes. Each zone can be independently selected to generate beam arrays with different characteristics, allowing beam current adjustment without requiring beam crossovers that cause Coulomb interactions and image blur.
Solution Approach 2:
Instead of adjusting beam current through temporal or spatial overlap (crossovers), the invention uses the dimensional variation of aperture sizes and patterns in the aperture plate to control beam current. This shifts the adjustment mechanism from beam path manipulation to aperture geometry selection, eliminating Coulomb interaction problems.
2Productivity
If multiple beam arrays are generated simultaneously, then productivity increases, but device complexity increases due to need for precise aberration control
Solution Approach 1:
Different zones in the aperture plate provide different aperture patterns and sizes tailored for different imaging requirements. This allows local optimization of beam characteristics for specific applications without requiring complex global aberration control systems, as each zone is designed to produce appropriate beam quality for its intended use.
Solution Approach 2:
The selector device enables dynamic switching between different beam arrays from different zones, allowing the system to adapt to different imaging tasks. This dynamic reconfiguration capability provides multi-beam productivity when needed while simplifying aberration control by selecting pre-optimized aperture patterns for specific applications.
3Device complexity
If aperture plate has fixed aperture pattern, then device complexity is reduced, but adaptability for different applications is limited
Solution Approach 1:
The aperture plate incorporates multiple zones with different aperture patterns and sizes within a single component, making it multi-functional. This universal aperture plate can generate different beam arrays suitable for various applications (multi-beam imaging, single-beam imaging, different beam currents) without requiring multiple separate aperture plates or complex reconfiguration mechanisms.
Solution Approach 2:
The aperture plate is segmented into multiple functional zones, each optimized for specific applications. This segmentation allows the single aperture plate to serve multiple purposes - generating different beam arrays with different currents and patterns - thereby increasing adaptability while maintaining relatively simple device structure.
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 design enhances flexible multi-beam generation and adjustment, reducing image blur and maintaining image brightness, while allowing for seamless transitions between multi-beam and single-beam modes to accommodate various applications.
Implementation Method 1
Producing a plurality of charged particle beams, by directing a progenitor charged particle beam onto an aperture plate having a corresponding plurality of apertures within a footprint of the progenitor beam
Data Source
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AI summary
A charged particle imaging apparatus comprising: - A specimen holder, for holding a specimen; - A particle-optical column, for: • Producing a plurality of charged particle beams, by directing a progenitor charged particle beam onto an aperture plate having a corresponding plurality of apertures within a footprint of the progenitor beam; • Directing said beams toward said specimen, wherein: - Said aperture plate comprises a plurality of different zones, which comprise mutually different aperture patterns, arranged within said progenitor beam footprint; - The particle-optical column comprises a selector device, located downstream of said aperture plate, for selecting a beam array from a chosen one of said zones to be directed onto the specimen.