Multi-Aperture Plate Energy Filtering for Multi-Beamlet Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multi-beamlet inspection systems lack effective energy filtering and cross-talk reduction capabilities, which are essential for achieving high contrast and throughput in charged particle detection systems.
Innovation Solution
A charged particle detection system with multiple aperture plates and a voltage supply configuration that aligns apertures and detection elements to allow only charged particles with kinetic energy above a threshold to reach the detector, while rejecting lower energy particles and using additional aperture plates for focussing and reducing cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional energy filters are used in multi-beamlet inspection systems, then image contrast is improved, but device complexity increases due to additional components in the beam path
Solution Approach 1:
The detector elements are designed to perform multiple functions: they act as both detection elements for charged particles and as energy filtering elements through their bias voltage. This eliminates the need for separate energy filter components in the beam path, reducing device complexity while maintaining image contrast improvement capabilities
Solution Approach 2:
The invention changes the operational parameters of the detector elements by applying specific bias voltages to create potential barriers. This parameter change enables the detector elements to filter charged particles based on their kinetic energy, providing energy filtering functionality without adding physical filter components to the system
2Measurement precision
If multiple aperture plates are added for energy filtering and cross-talk reduction, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The aperture plates serve dual functions: they define the geometric aperture for beamlet separation (preventing cross-talk) and, when combined with bias voltages, provide energy filtering. This multi-functionality improves measurement precision while minimizing the increase in device complexity by making existing components perform multiple roles
Solution Approach 2:
The aperture plates act as intermediary elements between the beamlet optics and the detector elements. They mediate the charged particle trajectories by providing both geometric confinement and energy-dependent potential barriers, thereby improving measurement precision without requiring direct modification of the detector elements or beam source
3Illumination intensity
If energy filtering is implemented to reject low energy particles, then image contrast is improved, but productivity decreases due to additional processing time
Solution Approach 1:
The invention replaces mechanical or physical energy filtering systems (which would require moving parts or complex magnetic/electric field configurations) with an electrostatic potential barrier approach using biased detector elements. This substitution provides energy filtering in a static, rapid manner that does not introduce additional processing delays, thereby maintaining productivity while improving image contrast
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
The system achieves improved energy filtering and reduced cross-talk, ensuring that only particles with sufficient energy are detected while maintaining high accuracy and preventing adjacent detection element interference.
Implementation Method 1
The electric potentials supplied to the first detector and the first aperture plate are provided such that only charged particles of a beamlet having a kinetic energy greater than a threshold energy can traverse the respective aperture of the first aperture plate to be incident on the respective detection element
Implementation Method 2
the first and second aperture plates provide a focussing effect on each of the plurality of the charged particle beamlets traversing the aperture plates
Data Source
AI summary
A charged particle detection system comprises plural detection elements and a multi-aperture plate in proximity of the detection elements. Charged particle beamlets can traverse the apertures of the multi-aperture plate to be incident on the detection elements. More than one multi-aperture plate can be provided to form a stack of multi-aperture plates in proximity of the detector. A suitable electric potential supplied to the multi-aperture plate can have an energy filtering property for the plural charged particle beamlets traversing the apertures of the plate.