Proximity Electrode Aperture Structure for Higher SNR Imaging
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Solution Overview
Problem
Current charged particle beam devices face limitations in achieving high-performance imaging and inspection on the micrometer and nanometer scale due to suboptimal electrode designs, which affect the passage of primary and signal charged particles, leading to reduced signal-to-noise ratio and contrast.
Innovation Solution
A proximity-electrode with a large aperture and radially cantilevering protrusions of n-fold rotational symmetry is introduced, enhancing signal charged particle collection while minimizing field penetration and shadowing, thereby improving imaging and inspection capabilities without deteriorating the primary beam spot size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the aperture of the proximity-electrode is enlarged to collect more signal charged particles, then the signal-to-noise ratio and contrast are improved, but the field penetration and shadowing effects increase
Solution Approach 1:
The electrode body is segmented with multiple protrusions extending into the aperture, dividing the aperture into multiple sub-apertures. This segmentation allows the electrode to maintain a large overall aperture for enhanced signal collection while the protrusions create individual smaller pathways that reduce field penetration and shadowing effects.
Solution Approach 2:
The protrusions are strategically positioned at specific locations within the aperture to create localized field control. This local quality modification allows different regions of the aperture to have different field characteristics, enabling optimized signal collection in some regions while minimizing harmful field penetration in others.
2Measurement precision
If the aperture of the proximity-electrode is enlarged to collect more signal charged particles, then the signal-to-noise ratio and contrast are improved, but the primary beam spot size deteriorates
Solution Approach 1:
The aperture is segmented into multiple sub-apertures by the protrusions, allowing the primary beam to pass through defined pathways while signal particles are collected from broader angles. This maintains beam focus quality while enhancing signal collection capability.
Solution Approach 2:
The protrusions extend radially into the aperture from the electrode body, adding a dimensional structure that controls field distribution without blocking the primary beam path. This three-dimensional structure enables simultaneous optimization of beam spot size and signal collection angle.
3Measurement precision
If the proximity-electrode is positioned closer to the sample to enhance signal collection, then the signal-to-noise ratio is improved, but the risk of electric arcing increases
Solution Approach 1:
The segmented aperture structure with protrusions creates multiple smaller electric field regions rather than one large continuous field. This segmentation reduces the overall field strength in each region, lowering the probability of electric arcing when the electrode is positioned close to the sample.
Solution Approach 2:
The protrusions modify the electric field distribution parameters by creating localized field concentrations and reductions in different regions. This parameter optimization allows the electrode to operate at closer distances to enhance signal collection while the field distribution changes prevent runaway field strengths that would cause arcing.
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 improved proximity-electrode design allows for increased signal charged particle collection and detection, enhancing signal-to-noise ratio, acquisition time, and contrast, while maintaining a comparable primary beam spot size and reducing the risk of electric arcing.
Implementation Method 1
a retarding field device for retarding the primary charged particle beam before the primary charged particle beam impinges on the sample
Implementation Method 2
the retarding field device comprising an objective lens and a proximity-electrode arranged downstream of a principal plane of the objective lens; wherein the charged particle beam device is adapted for guiding the primary charged particle beam along an optical axis to the sample
Data Source
AI summary
A proximity-electrode for a charged particle beam device is provided, the proximity-electrode including a body having an aperture within the body, and the body having a plurality of protrusions cantilevering radially into the aperture, and the aperture and the protrusions having an n-fold rotational symmetry, where n is an integer.