FIB Lamella Preparation Using Preferred Milling Axis Selection
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Solution Overview
Problem
Existing methods for preparing samples for charged particle microscopy, such as focused ion beam milling, often result in artifacts like curtaining due to differences in material properties, leading to non-uniform lamella thickness and diminished analysis quality.
Innovation Solution
The method involves using a controller to produce projected sample characterization values for various processing axes and identifying a preferred axis to minimize artifacts. This is achieved by rotating the sample specimen to align with the preferred processing axis, allowing for more uniform FIB milling and reduced curtaining effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If FIB milling is performed on samples with non-uniform material properties, then material removal occurs, but curtaining artifacts and non-uniform lamella thickness are produced
Solution Approach 1:
The system performs preliminary imaging and analysis of the sample to identify material property variations and determine the optimal processing axis before FIB milling begins. This preliminary characterization allows the system to plan the milling path to avoid or minimize curtaining artifacts by selecting directions that traverse material interfaces more favorably.
Solution Approach 2:
The system changes the processing parameters dynamically by adjusting the ion beam direction along different processing axes based on the identified material properties. By varying the beam incidence angle and selecting optimal processing directions, the system adapts the milling process to accommodate non-uniform material properties and reduce artifact formation.
2Manufacturing precision
If multiple processing axes are evaluated to find the preferred axis, then artifact reduction is achieved, but processing time and system complexity increase
Solution Approach 1:
The system evaluates a limited set of discrete processing axes rather than performing a complete 360-degree analysis. By selecting a representative subset of candidate axes and evaluating only those, the system achieves sufficient artifact reduction without the time cost of exhaustive evaluation of all possible directions.
Solution Approach 2:
The system uses automated image processing and computational algorithms to evaluate processing axes based on projected sample characterization values, replacing manual trial-and-error approaches. This computational method rapidly assesses multiple axes and identifies the preferred direction without requiring physical testing of each orientation.
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 enables the preparation of thin, uniform samples suitable for charged particle microscopy, reducing artifacts and enhancing the quality of material analysis, even with samples having non-uniform material properties.
Implementation Method 1
processing, with a focused ion beam (FIB) system of the CPM system, the sample specimen to produce a lamella
Data Source
AI summary
In an example, a method includes producing a set of projected sample characterization values associated with each of a plurality of processing axes and identifying a preferred processing axis based on the projected sample characterization values. In another representative example, a method includes extracting a sample specimen, producing a sample image of the sample specimen, identifying a preferred sample tilt angle, and rotating the sample specimen to an orientation corresponding to a preferred sample tilt angle. The method further includes processing the sample specimen to produce a lamella. In another representative example, a system includes a focused ion beam (FIB) system, a sample holder, a stage, and a controller operable to cause the stage to rotate the sample specimen relative to the ion beam axis such that the ion beam approaches the sample specimen along a preferred processing axis.