Multi-pillar Sample for Wide Tilt Range Tomography
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Solution Overview
Problem
Lamella tomography is limited by a restricted tilt range due to sample carrier obstructions and varying effective sample thickness, leading to reduced image quality and limited information in tomographic reconstructions.
Innovation Solution
A multi-pillar sample is used, where pillars extend from a substrate, allowing for a wider tilt range and reduced obstruction by arranging pillars in a spaced series, enabling full 360-degree imaging with minimal interference from adjacent pillars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thin lamella sample is used for tomography, then the sample can be imaged in transmission electron microscope, but the tilt range is limited to -70/+70 degrees due to sample carrier obstruction
Solution Approach 1:
The invention segments the sample into multiple separate pillars mounted on the sample carrier, rather than using a single continuous lamella. This segmentation allows each pillar to be imaged independently with a full tilt range, as the spaces between pillars eliminate mutual obstructions that would limit the tilt angle in a continuous lamella sample.
Solution Approach 2:
The invention transitions from a two-dimensional lamella sample to a three-dimensional arrangement of multiple pillars standing upright on the carrier. This dimensional change allows the electron beam to pass through each pillar from multiple angles without being blocked by the sample carrier edges, enabling a tilt range exceeding ±70 degrees.
2Loss of information
If the sample is tilted to higher angles for extended tilt range, then more information can be obtained, but the effective thickness of the sample increases and attenuates the electron beam
Solution Approach 1:
By dividing the sample into multiple discrete pillars, the invention enables the electron beam to pass through thinner effective paths at high tilt angles. The gaps between pillars reduce the cumulative thickness the beam must traverse, minimizing attenuation while still allowing access to high tilt angles for comprehensive tomographic information.
3Measurement precision
If multiple separate samples are prepared and imaged individually, then each sample can be imaged with optimal conditions, but the process time and complexity increase
Solution Approach 1:
The invention merges multiple separate pillar samples onto a single sample carrier, allowing all pillars to be imaged simultaneously in one experiment. This combining approach maintains the image quality benefits of individual sample imaging while dramatically reducing the total imaging time and procedural complexity compared to processing multiple separate samples.
Solution Approach 2:
The sample carrier is designed to serve multiple functions: it holds multiple pillars in fixed positions and allows the entire assembly to be tilted and imaged as a single unit. This multi-functionality enables the carrier to support both individual pillar imaging and collective tomographic acquisition, optimizing both image quality and efficiency.
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 enhances the tilt range for tomographic imaging, reduces image quality degradation, and increases the amount of data obtainable from samples, improving the efficiency and quality of 3D reconstructions.
Implementation Method 1
directing a charged particle beam to the first pillar, imaging the first pillar at a plurality of rotational positions
Data Source
AI summary
Methods include providing a multi-pillar sample including at least a first pillar and a second pillar parallel with the first pillar, directing a charged particle beam to the first pillar, imaging the first pillar at a plurality of rotational positions by rotating the multi-pillar sample about a first pillar axis of the first pillar, directing the charged particle beam to the second pillar, and imaging the second pillar at a plurality of rotational positions by rotating the multi-pillar sample about a second pillar axis of the second pillar. Related apparatus for performing disclosed methods are disclosed. Multi-pillar samples are also disclosed.