TEM Sample Extraction via Focused Ion Beam Drilling and Electrostatic Transfer
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Solution Overview
Problem
Current methods for preparing samples for transmission electron microscopes and scanning transmission electron microscopes are time-consuming and inefficient, often requiring destruction of the substrate or extensive thinning of samples, and may introduce contaminants or require welding, which complicates the sample handling process.
Innovation Solution
The method involves using a focused ion beam to drill a hole in the sample and attach a probe for transport and processing, allowing for in-situ sample extraction and orientation preservation, or using electrostatic attraction to transfer the sample directly to a TEM or STEM sample holder within the vacuum chamber, eliminating the need for welding and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sample extraction methods (diamond saw cutting, mechanical polishing, FIB thinning) are used, then sample thickness is reduced to suitable levels for TEM/STEM viewing, but the process is time-consuming and destroys the substrate
Solution Approach 1:
The method performs preliminary actions by first drilling a hole through the substrate to the sample, then freeing the sample within the substrate, and finally attaching it to a probe before removal. This sequence of preliminary actions enables rapid extraction without requiring time-consuming post-extraction thinning operations, thus improving productivity while maintaining manufacturing precision.
Solution Approach 2:
The invention extracts the sample from the substrate using a focused ion beam to drill a hole and free the sample, then attaches it to a probe for removal. This extraction method eliminates the need for extensive in-situ thinning operations, significantly reducing preparation time while preserving sample integrity and orientation.
2Ease of operation
If FIB welding is used to attach sample to probe, then sample can be transported and processed, but the process becomes more complex and time-consuming
Solution Approach 1:
The invention replaces the mechanical FIB welding process with electrostatic attraction. By applying a voltage to the probe, the sample is attracted and held in place without requiring complex welding operations. This substitution maintains sample transport capability while dramatically simplifying the attachment process and reducing overall complexity.
Solution Approach 2:
The method changes the attachment mechanism from mechanical (welding) to electrical (electrostatic attraction). By controlling the voltage parameter applied to the probe, the sample can be easily attached and detached without complex mechanical operations, thus improving ease of operation while reducing device complexity.
3Adaptability or versatility
If sample is removed from vacuum chamber for processing, then extensive manipulation is possible, but contamination risk increases and time is lost
Solution Approach 1:
The invention maintains the sample within the vacuum chamber environment throughout the extraction and attachment process. The vacuum chamber serves as a protected, contamination-free environment, eliminating exposure to atmospheric contaminants while still allowing for probe attachment and sample manipulation via electrostatic forces.
Solution Approach 2:
The probe acts as an intermediary that enables sample manipulation and transport within the vacuum chamber without requiring sample removal. The electrostatically attached probe allows for in-situ processing and positioning, maintaining sample integrity while providing the versatility needed for various processing operations.
4Ease of manufacture
If substrate is destroyed to extract sample, then sample extraction is simplified, but substrate reuse becomes impossible
Solution Approach 1:
The invention extracts only the specific sample region from the substrate using a focused ion beam to drill a hole and free the sample. This selective extraction preserves the surrounding substrate material, allowing it to remain intact and potentially reusable, thus reducing substrate loss while maintaining extraction simplicity.
Solution Approach 2:
The method segments the substrate by creating a localized hole and freeing only the specific sample region needed. This segmentation approach allows the sample to be extracted while leaving the rest of the substrate intact, enabling substrate reuse and reducing material loss while maintaining extraction 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 simplifies and accelerates the sample extraction process, preserves sample orientation, and reduces contamination by allowing for in-situ handling and processing, enhancing the efficiency of sample preparation for electron microscopy.
Implementation Method 1
a hole is drilled in the sample using a focused ion beam
Implementation Method 2
using electrostatic attraction to transfer the sample directly to a TEM or STEM sample holder
Data Source
AI summary
Methods of extracting a TEM sample from a substrate include milling a hole on the sample and inserting a probe into the hole. The sample adheres to the probe, and can be processed on transferred while on the probe. In another embodiment, the sample is freed from a substrate and adheres to a probe by electrostatic attraction. The sample is placed onto a TEM sample holder in a vacuum chamber.