SPM Probe Thinning TEM Specimens for Sub-100 nm Precision
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Solution Overview
Problem
The production of extremely thin TEM specimens is difficult, as existing methods like Focused Ion Beam milling often cannot thin specimens to less than 100 nm without complex and costly processes, and combining TEM with SPM techniques is technically complex and rarely documented.
Innovation Solution
A method and apparatus that uses a Scanning Probe Microscopy (SPM) probe to thin TEM specimens by scratching the surface, allowing for progressive thinning and simultaneous or subsequent SPM acquisition, enabling 3D tomographic data collection without back projection algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Focused Ion Beam milling is used to thin TEM specimens, then specimen thickness is reduced, but the process becomes complex and costly, and cannot achieve thickness below 100 nm without additional complex steps
Solution Approach 1:
The patent combines TEM imaging capability with SPM thinning capability in a single integrated system. The SPM probe is positioned within the TEM column, allowing simultaneous or sequential thinning and imaging operations on the same specimen without removing it from the instrument. This integration eliminates the need for separate FIB milling equipment and multiple specimen handling steps, thereby reducing overall process complexity while achieving atomic-layer precision thinning to below 100 nm.
2Manufacturing precision
If Focused Ion Beam milling is used to thin TEM specimens to less than 100 nm, then specimen thickness is reduced, but multiple complex manipulations are required
Solution Approach 1:
The system performs self-service by using the TEM column itself to provide both the imaging environment and the thinning mechanism. The SPM probe, positioned within the existing TEM vacuum chamber and electron beam path, thins the specimen in situ without requiring removal to external FIB equipment. This self-contained approach eliminates multiple specimen manipulations and transfers, making the thinning process simpler and more straightforward while achieving the required sub-100 nm thickness.
3Adaptability or versatility
If TEM and SPM are combined, then multi-functional analysis is enabled, but the technical complexity increases and documentation is scarce
Solution Approach 1:
The patent implements universality by designing the SPM probe to serve multiple functions within the TEM system. The same probe can perform topographical mapping, electrical property measurements, and mechanical thinning operations. The integrated system allows users to switch between TEM imaging, SPM scanning, and thinning modes using a single instrument platform, thereby enabling multi-functional analysis without requiring separate specialized equipment for each technique.
4Manufacturing precision
If conventional TEM specimen preparation is used, then electron transparency is achieved, but thickness cannot be reduced to very low values without complex processes
Solution Approach 1:
The patent replaces conventional mechanical and ion-based thinning methods with a controlled mechanical scratching process using an SPM probe. Instead of using FIB milling or complex multi-step mechanical thinning, the SPM probe applies controlled forces to scratch and remove material layer by layer. This mechanical substitution approach, performed within the TEM column, achieves very low thickness values while simplifying the preparation process and improving ease of manufacture.
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
Enables thinning of TEM specimens to very low thickness without complex operations, allowing for straightforward 3D tomographic data acquisition of structural and electrical characteristics, overcoming the limitations of existing techniques by physically removing layers and avoiding projection artifacts.
Implementation Method 1
at least an area of the specimen is thinned by scratching a surface of the specimen with a probe suitable for Scanning Probe Microscopy (SPM)
Implementation Method 2
the thinned area is exposed to an electron beam and a TEM image is taken of the thinned area
Data Source
Figure 1a~2b
Figure 3
Figure 4
AI summary
The invention is related to a method and apparatus for transmission electron microscopy wherein a TEM specimen (1,12) is subjected to at least one thinning step by scratching at least an area of the specimen with an SPM probe (4), and wherein the thinned area is subjected to an SPM acquisition step, using the same SPM probe or another probe.