Charged-particle microscope depth-resolved imagery via emergence angle deconvolution
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Solution Overview
Problem
Current methods for acquiring depth-resolved imagery in charged-particle microscopy require multiple measurements at different beam energies, leading to increased radiation exposure and sample damage, especially for delicate samples.
Innovation Solution
A method that records detector output as a function of emergence angle and uses computer processing to deconvolve the data, allowing for depth-resolved imaging without the need for multiple beam energy measurements, by defining a Point Spread Function and minimizing divergence between observed and computed images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measurements at different beam energies are performed to acquire depth-resolved imagery, then depth resolution is improved, but radiation exposure and sample damage increase
Solution Approach 1:
The patent changes the detection parameter from beam energy to emergence angle. Instead of acquiring images at multiple beam energies to achieve depth resolution, the method acquires images at multiple emergence angles and uses computational deconvolution to extract depth information. This parameter substitution eliminates the need for repeated high-energy beam exposure, thereby reducing radiation damage while maintaining depth resolution capability
Solution Approach 2:
The patent replaces the physical/mechanical approach of varying beam energy with a computational approach. Rather than physically adjusting beam energy multiple times to probe different depths, the method uses mathematical deconvolution of data collected at different emergence angles to reconstruct depth-resolved images, substituting computational processing for physical parameter variation
2Measurement precision
If multiple measurements at different beam energies are performed to acquire depth-resolved imagery, then depth resolution is improved, but imaging time increases
Solution Approach 1:
By changing the acquisition parameter from beam energy to emergence angle, the method enables parallel or sequential data collection that is more time-efficient. Multiple emergence angles can be acquired in a single scanning pass or with minimal reconfiguration, whereas multiple beam energy measurements require time-consuming energy transitions and repeated scanning, thus reducing total imaging time
3Object-affected harmful factors
If emergence angle data is collected and deconvolved to achieve depth resolution, then sample damage is reduced, but device complexity increases
Solution Approach 1:
The patent substitutes complex physical measurement systems (multiple beam energy configurations) with a computational data processing system. The complexity is shifted from hardware configuration to software algorithms, specifically deconvolution algorithms that process emergence angle data to reconstruct depth-resolved images. This computational approach reduces sample damage while managing complexity through software rather than hardware
4Measurement precision
If traditional multi-energy beam measurements are used, then depth information is obtained, but productivity decreases
Solution Approach 1:
The patent enables continuous data acquisition at different emergence angles during a single beam scan, rather than interrupting the process for multiple energy transitions. This continuous approach maintains beam-on time and eliminates idle periods associated with energy switching, thereby improving imaging speed and productivity while still extracting depth information through angular variation and computational processing
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 approach enables efficient and non-destructive depth-resolved imaging, reducing sample damage and improving imaging speed by converting raw measurement data into spatially resolved results, effectively performing a 'depth-from-angle' conversion.
Implementation Method 1
Using a particle-optical column to direct at least one beam of particulate radiation onto a surface S of the sample, thereby producing an interaction that causes emitted radiation to emanate from the sample
Implementation Method 2
Using a detector arrangement to detect at least a portion of said emitted radiation
Implementation Method 3
Using computer processing apparatus to automatically deconvolve the measurement set M and spatially resolve it into a result set R = {(V k , L k )}, in which a spatial variable V demonstrates a value V k at an associated discrete depth level L k referenced to the surface S
Implementation Method 4
Defining a Point Spread Function that, for each value of n, has a kernel value K n representing a behavior of said beam of particulate radiation in a bulk of the sample
Data Source
Figure 1A
Figure 1B
Figure 2(A)~2(C)
AI summary
A method of examining a sample using a charged-particle microscope, comprising the following steps: - Mounting the sample on a sample holder; - Using a particle-optical column to direct at least one beam of particulate radiation (IB) onto a surface S of the sample, thereby producing an interaction that causes emitted radiation (A, B, C, D) to emanate from the sample; - Using a detector arrangement to detect at least a portion of said emitted radiation, which method comprises the following steps: - Recording an output On of said detector arrangement as a function of emergence angle θn of said emitted radiation, measured relative to an axis normal to S, thus compiling a measurement set M = {(On, θn)} for a plurality of values of θn; - Using computer processing apparatus to automatically deconvolve the measurement set M and spatially resolve it into a result set R = {(Vk, Lk)}, in which a spatial variable V demonstrates a value Vk at an associated discrete depth level Lk referenced to the surface S, whereby n and k are members of an integer sequence, and spatial variable V represents a physical property of the sample as a function of position in its bulk.