Multi-Beam Electron Microscope Backscatter Conversion for Image Contrast
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Solution Overview
Problem
Multi-beam particle microscopes struggle to visualize certain structures with high contrast in electron microscopic images due to inefficient detection of backscattered electrons, which are essential for distinguishing different materials.
Innovation Solution
A multi-beam particle microscope equipped with a multi-aperture plate featuring converters that transform high-energy backscattered electrons into lower-energy electrons, allowing them to be detected alongside secondary electrons, enhancing the visibility of material contrasts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-beam particle microscope is used to increase scanning efficiency, then productivity is improved, but the ability to detect backscattered electrons with high contrast deteriorates
Solution Approach 1:
The detector array is segmented into multiple individual detectors, each assigned to detect secondary electrons from a specific primary beam impact location. This segmentation allows simultaneous detection of multiple electron beams without signal mixing, maintaining measurement precision while improving productivity through parallel processing
Solution Approach 2:
A multi-aperture plate with converters is introduced as an intermediary component between the object and detector array. The converters on the plate transform backscattered electrons into detectable signals while maintaining spatial correspondence with primary beam locations, enabling high-contrast backscattered electron detection in the multi-beam configuration
2Measurement precision
If converters are added to the multi-aperture plate to detect backscattered electrons, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The converter function is merged with the existing multi-aperture plate structure. The converters are integrated directly onto the plate that already serves to define and separate individual electron beam paths, eliminating the need for separate converter components and reducing overall device complexity
Solution Approach 2:
The multi-aperture plate is designed to serve multiple functions: it defines individual beam paths through its aperture structure, houses converters for backscattered electron detection, and maintains spatial registration between primary beams and detectors. This multi-functionality reduces the number of separate components needed
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 enables the efficient detection of backscattered electrons, improving the contrast and visibility of material differences in electron microscopic images, comparable to single-beam microscopes.
Implementation Method 1
the converters are configured to convert backscattered electrons generated by the primary particle beams at the object, which have kinetic energies at the object that are greater than a predetermined first energy threshold, into electrons that have kinetic energies at the converter that are smaller than a predetermined second energy threshold
Implementation Method 2
an objective lens through which beam paths of the plurality of primary particle beams pass and which is configured to direct the plurality of primary particle beams onto an object plane and to focus them there
Implementation Method 3
a detector arrangement configured to detect intensities of a plurality of electron beams
Data Source
Figure 1
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AI summary
The invention relates to a multi-beam electron microscope having a multi-beam electron source (300), an objective lens (102), a detector arrangement (200) and a multiple-aperture plate (11) which has a plurality of openings and is arranged between the objective lens (102) and the object plane (101). The multiple-aperture plate comprises a plurality of converters which convert backscatter electrons generated from primary particle beams on an object into electrons of lower energy, which provide electrons which form the electron beams detected by the detector arrangement.