Aperture Unit Electromagnetic Positioning for Beam Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing particle beam apparatuses face challenges in reproducibly setting beam current and achieving a mode-independent beam path due to mechanical imprecision and hysteresis, particularly when using piezoelectric elements for aperture unit positioning.
Innovation Solution
The apparatus features independently adjustable pole shoes for the condenser lenses and a pressure stage aperture unit with a thin-film design, allowing continuous variation of beam current from 10 pA to 300 nA, and includes a deflection system to maintain a mode-independent beam path, utilizing adjustable aperture openings and drive units like piezoelectric elements and bimetal elements for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezoelectric elements are used for aperture unit positioning, then beam current can be varied continuously, but mechanical imprecision and hysteresis reduce reproducibility
Solution Approach 1:
The patent replaces the mechanical positioning system (piezoelectric elements) with an electromagnetic positioning system. The aperture unit is positioned by electromagnetic forces generated by coils, eliminating the mechanical contact and associated hysteresis effects. This substitution maintains continuous beam current variation capability while significantly improving reproducibility by removing mechanical imprecision.
Solution Approach 2:
The patent changes the control parameter from mechanical displacement to electromagnetic field strength. By controlling the current through positioning coils rather than mechanically displacing piezoelectric elements, the system achieves the same aperture positioning function with improved reproducibility. The electromagnetic field parameters can be precisely controlled and reproduced without the hysteresis inherent in mechanical systems.
2Measurement precision
If aperture unit is fixed for high-resolution mode, then image resolution is improved, but beam current cannot be increased for other analysis methods
Solution Approach 1:
The patent makes the aperture unit dynamically adjustable rather than fixed. The aperture opening size can be changed in real-time by controlling the electromagnetic positioning system, allowing the system to adapt between high-resolution mode (small aperture) and high-current mode (large aperture). This dynamic adjustment capability resolves the contradiction by enabling both high resolution and high current operation at different times.
Solution Approach 2:
The patent creates a universal aperture positioning system that serves multiple functions. The same electromagnetic positioning mechanism enables both high-resolution imaging (with small aperture openings) and various analysis methods requiring higher beam currents (with larger aperture openings). This multi-functional design eliminates the need for fixed aperture configurations and provides adaptability across different operational modes.
3Ease of operation
If mechanical aperture positioning system is used, then aperture opening can be adjusted, but mechanical imprecision affects beam path consistency
Solution Approach 1:
The patent substitutes electromagnetic positioning for mechanical aperture adjustment. Instead of using mechanical components that introduce imprecision and affect beam path consistency, the system uses electromagnetic fields to position the aperture unit. This elimination of mechanical contact points ensures that aperture adjustments do not compromise beam path consistency while maintaining ease of operation through electromagnetic control.
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 configuration enables precise and reproducible setting of beam current across a wide range, ensuring high-resolution imaging and mode-independent operation, improving image resolution and reducing mechanical errors.
Implementation Method 1
a first aperture element and a second aperture element which cooperate to form an aperture opening and are movable relative to one another, in particular by means of a piezoelectric element
Implementation Method 2
at least one drive unit for moving the first aperture element and/or the second aperture element
Data Source
AI summary
A particle beam apparatus includes a first aperture unit having an adjustable aperture opening. The particle beam apparatus may include a first condenser lens having a first pole shoe and a second pole shoe. Both the first pole shoe and the second pole shoe may be adjustable relative to a second aperture unit independently of each other. The second aperture unit may be designed as a pressure stage aperture separating a first area having a vacuum at a first pressure, and a second area having a vacuum at a second pressure. Additionally, a method for adjusting a beam current in a particle beam apparatus is provided.