Sample Holder Orientation Control for FIB-to-TEM Tomography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Charged particle microscope samples with thicknesses less than 300 nm are fragile and prone to misalignment during handling and transfer, leading to rotation misalignments and undesired gamma tilt, which reduces the accessible area for tomography and increases image obstruction during analysis.
Innovation Solution
A sample holder with a defined Z-axis perpendicular to the sample holder plane and a gamma rotation axis is used to maintain the sample's orientation during focused ion beam milling and subsequent transfer to a charged particle microscope, ensuring correct alignment with the tilt axis of the microscope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual handling steps are used to transfer the sample holder between DualBeam and TEM, then the transfer process is simple and quick, but misalignment occurs causing the milling axis to be incorrectly aligned with respect to the TEM tilt-axis
Solution Approach 1:
The patent introduces a specialized sample holder with defined geometric features (flat side, rounded side, diagonal side) that acts as an intermediary between the DualBeam and TEM systems. These features serve as mechanical references that ensure the milling axis remains correctly aligned with the TEM tilt-axis during manual transfer, eliminating the misalignment problem while maintaining simple manual handling.
Solution Approach 2:
The sample holder is pre-configured with specific geometric features before transfer that predetermined the correct orientation and alignment. The flat side, rounded side, and diagonal side are designed in advance to guide the sample holder into the correct position during manual loading, preventing misalignment before it occurs.
2Ease of operation
If the sample is mounted on a thin round foil grid for handling, then the fragile sample can be manipulated and transported, but the sample becomes prone to misalignment and rotation during handling and transfer
Solution Approach 1:
The patent segments the sample holder into distinct functional zones with specific geometric features (flat side, rounded side, diagonal side) that serve different purposes. These segmented features work together to provide both easy handling through defined orientation markers and reliable alignment stability through mechanical reference surfaces that prevent rotation during transfer.
3Ease of manufacture
If the sample holder lacks defined orientation features, then the design is simple and manufacturing is easier, but gamma rotation misalignment occurs during transfer to the charged particle microscope
Solution Approach 1:
The patent employs asymmetric geometric features on the sample holder including a flat side, a rounded side, and a diagonal side. These asymmetric features are straightforward to manufacture but effectively prevent gamma rotation misalignment by providing unique orientation references that cannot be confused with any other rotation position, ensuring precise alignment during transfer.
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 method and sample holder design prevent misalignment and maintain the sample's orientation, reducing blockage and enhancing resolution during tomography by ensuring the sample remains correctly positioned and unobscured, thus improving the accuracy and clarity of image acquisition.
Implementation Method 1
a focused ion beam is used to remove at least part of the sample to provide a milled sample
Implementation Method 2
Irradiating a region of interest on the milled sample with a charged particle beam of said charged particle microscope
Implementation Method 3
Position-dependent information in the form of secondary particles, such as secondary electrons and X-rays, is produced
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides a method of sample preparation and analysis and a sample holder that may be used in said method.