Multi-Beam Aperture Arrays for Coulomb-Limited Imaging Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multi-beam charged particle microscopes face limitations in imaging resolution due to Coulomb interaction effects, which broaden the electron beam and reduce resolution, especially when trying to maintain high throughput and accommodate varying beam currents and positions.
Innovation Solution
A charged-particle beam apparatus with a first aperture array generating primary beamlets and a second aperture array forming probing beamlets, using a condenser lens to adjust the portion of charged particles and modify beam currents, while maintaining mechanical integrity and reducing Coulomb interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electron beams are used to increase throughput, then productivity is improved, but imaging resolution deteriorates due to Coulomb interaction effects
Solution Approach 1:
The patent divides the electron beam into multiple separate beamlets using aperture arrays, allowing each beamlet to be processed independently. This segmentation enables multiple beams to operate simultaneously (improving throughput) while maintaining sufficient separation to reduce Coulomb interactions between electrons in different beams, thereby preserving imaging resolution.
Solution Approach 2:
The patent introduces spatial separation in the form of multiple aperture arrays positioned at different locations and orientations. By distributing beams across multiple spatial dimensions and using aperture arrays at different planes, the system achieves high throughput through parallel processing while maintaining resolution through geometric separation that mitigates Coulomb effects.
2Measurement precision
If beam current is increased to maintain signal strength, then measurement precision is improved, but Coulomb effects worsen and reduce resolution
Solution Approach 1:
The patent segments the total electron beam into multiple smaller beamlets through aperture arrays. Each beamlet carries a portion of the total current, distributing the signal strength across multiple independent beams. This allows the system to maintain adequate signal strength through the combined effect of multiple beamlets while reducing the electron density in each individual beamlet, thereby minimizing Coulomb interactions and preserving resolution.
3Adaptability or versatility
If aperture size is increased to accommodate beam position variations, then adaptability is improved, but Coulomb effects increase and resolution deteriorates
Solution Approach 1:
The patent uses multiple small apertures arranged in arrays rather than a single large aperture. This segmentation allows the system to accommodate beam position variations by selecting different subsets of apertures or adjusting which apertures are active, providing adaptability without requiring any individual aperture to be large. The small size of each aperture maintains low electron density and reduces Coulomb effects, preserving resolution while achieving positional flexibility through the array configuration.
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 solution enhances imaging resolution by mitigating Coulomb effects, allowing for a range of beam currents and positions, improving defect detection accuracy in integrated circuit inspection.
Implementation Method 1
a charged-particle source configured to generate a primary charged-particle beam
Implementation Method 2
a condenser lens comprising a plane adjustable along the primary optical axis
Implementation Method 3
a first aperture array comprising a first plurality of apertures configured to generate a plurality of primary beamlets
Data Source
AI summary
Systems and methods of mitigating Coulomb effect in a multi-beam apparatus are disclosed. The multi-beam apparatus may include a charged-particle source configured to generate a primary charged-particle beam along a primary optical axis, a first aperture array comprising a first plurality of apertures having shapes and configured to generate a plurality of primary beamlets derived from the primary charged-particle beam, a condenser lens comprising a plane adjustable along the primary optical axis, and a second aperture array comprising a second plurality of apertures configured to generate probing beamlets corresponding to the plurality of beamlets, wherein each of the plurality of probing beamlets comprises a portion of charged particles of a corresponding primary beamlet based on at least a position of the plane of the condenser lens and a characteristic of the second aperture array.