Macrolamella Reorientation for Deep ROI Microsample Preparation
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Solution Overview
Problem
Existing methods for making a region of interest (ROI) deep within a sample block accessible for FIB-SEM analysis are time-consuming and prone to damage, especially when the ROI is located at a significant depth from the sample surface, as they often require extensive material removal or are inefficient in controlling the processing depth.
Innovation Solution
A method using a microscope system with a first and second particle beam to create a macrolamella by removing sample material, allowing the ROI to be exposed by orienting the macrolamella at an angle to the particle beam, facilitating lateral material removal and accelerating the preparation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If large amounts of sample material are removed to make the ROI accessible, then the ROI becomes accessible for microscopy, but the ROI may be damaged or inadvertently removed during the coarse removal process
Solution Approach 1:
The material removal process is segmented into two distinct stages: (1) coarse removal of large sample volumes using a laser beam to expose the ROI, and (2) fine removal of remaining material using a focused ion beam (FIB) to precisely expose the ROI without damage. This segmentation allows each process to be optimized for its specific function, resolving the contradiction between accessibility and integrity.
Solution Approach 2:
The laser beam performs preliminary coarse removal of sample material before the FIB process begins. This preliminary action reduces the depth that the FIB must remove, allowing the FIB to focus on precise, damage-free exposure of the ROI while the laser handles the bulk material removal that would be too time-consuming for FIB alone.
2Ease of operation
If FIB is used to remove large sample volumes in vertical processing direction, then the ROI can be accessed, but the process is extremely time-consuming
Solution Approach 1:
The material removal task is segmented between two tools: the laser beam handles the time-consuming bulk removal of large volumes, while the FIB handles the precise final exposure. This segmentation assigns the volumetric removal task to the faster laser process, dramatically reducing total preparation time compared to using FIB for the entire removal task.
Solution Approach 2:
The mechanical FIB milling process is partially replaced by laser ablation for the coarse removal stage. Laser ablation can remove material much faster than FIB milling, so substituting the laser for the FIB in the coarse removal phase significantly increases productivity while the FIB completes the precise final exposure.
3Productivity
If laser is used for top-down material removal, then large volumes can be removed quickly, but the removal is inhomogeneous and target depth control is difficult
Solution Approach 1:
The removal process is segmented into laser-based coarse removal (prioritizing speed) followed by FIB-based fine removal (prioritizing precision). The laser handles the inhomogeneous bulk removal efficiently, while the FIB corrects and completes the exposure with precise depth control, combining the advantages of both methods.
Solution Approach 2:
The FIB process acts as an intermediary that follows up on the laser removal. It corrects the inhomogeneities introduced by the laser and provides the precise depth control that the laser cannot achieve alone, mediating between the fast but imprecise laser removal and the final precision requirements.
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 enables rapid and reliable access to deep ROIs by converting impractical removal depths into manageable lateral lengths, thereby speeding up microsample preparation and reducing the risk of damage.
Implementation Method 1
removing sample material using the first particle beam or the second particle beam
Data Source
AI summary
A method prepares a microsample from a volume sample using multiple particle beams. The method includes providing a volume sample in the microscope system, wherein the interior of the volume sample has a sample region of interest, and producing a macrolamella comprising the sample region of interest by removing sample material of the volume sample using one of the particle beams. The method also includes orienting the macrolamella relative to one of the particle beams, and removing sample material of the macrolamella via a beam so that the region of interest is exposed.