Cooled Microprobe for Cryo-TEM Sample Transfer
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Solution Overview
Problem
Current methods for preparing thin film samples using charged particle beam devices, such as TEM or STEM, face challenges in maintaining sample integrity and accuracy due to temperature changes and frost contamination, leading to potential sample degradation and poor throughput when processing sensitive materials like liquids or biological samples.
Innovation Solution
A method utilizing a microprobe with a cooling mechanism, a first sample holder for retaining samples in a cooled state, and a second sample holder for thin film observation within a vacuum chamber, allowing for precise cutting and thin film processing of bulk samples while maintaining the sample in a cooled state, thereby preventing frost adherence and sample contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cryo-microtome method using a cooled knife is employed to prepare a thin film of a frozen sample, then the sample can be processed without temperature changes, but the processing position accuracy relative to the desired portion of observation is poor
Solution Approach 1:
The device is divided into two independent sample holders: a first sample holder for freezing and a second sample holder for thin film preparation. This segmentation allows each holder to be optimized for its specific function while maintaining sample integrity throughout the process.
Solution Approach 2:
A cooled microprobe acts as an intermediary tool to transfer the frozen sample from the first sample holder to the second sample holder. The microprobe maintains cooling during transfer, preventing frost adherence while enabling precise positioning for thin film preparation.
2Manufacturing precision
If a microprobe without cooling mechanism is used to extract the desired portion of observation, then processing position accuracy is improved, but the sample must be returned to ambient temperature causing damage or throughput degradation
Solution Approach 1:
The microprobe is equipped with a cooling mechanism that changes its temperature parameter from ambient to cooled state. This allows the microprobe to maintain the sample in a frozen state during extraction and transfer operations, preventing temperature-induced damage while preserving processing precision.
3Reliability
If the sample is mounted in a cooled state in a processing device, then sample quality is maintained, but frost can adhere to the sample surface during processing or observation
Solution Approach 1:
The frozen sample is extracted from the first sample holder using a cooled microprobe and transferred to a second sample holder within the vacuum chamber. This extraction process occurs in a controlled environment that prevents frost adherence while maintaining sample cooling.
Solution Approach 2:
The transfer and thin film preparation processes occur within a vacuum chamber environment. This inert atmosphere prevents moisture condensation and frost adherence on the cooled sample surface during processing operations.
4Object-affected harmful factors
If a frost adherence prevention cover is used during holder transport, then frost adherence is prevented, but the cover is ineffective during processing or observation inside the vacuum device
Solution Approach 1:
The cooling action continues throughout the entire process from the first sample holder through transfer to the second sample holder. This continuous cooling, combined with the vacuum environment, eliminates the need for intermittent frost prevention covers that would need to be removed during processing.
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 high-accuracy thin film sample preparation without degrading the sample quality, allowing for stable observation of heat-sensitive materials in their original shape, while minimizing thermal damage and contamination risks.
Implementation Method 1
a microprobe having a cooling mechanism... adhering the sample to a distal end of the microprobe that is cooled to a fixed temperature
Implementation Method 2
Scanning Electron Microscopy (hereinafter referred to as "SEM"), Transmission Electron Microscopy (hereinafter referred to as "TEM"), or Scanning Transmission Electron Microscopy (hereinafter referred to as "STEM")
Implementation Method 3
A Focused Ion Beam (hereinafter referred to as "FIB") device is used... A method for FIB processing an observation portion into a thin film shape
Data Source
AI summary
The present invention enables a sample to be observed in a clean state directly after preparation of a final observation surface when preparing a sample for observing a material that is sensitive to heat. The present invention is a method of preparing a sample using a charged particle beam device including a microprobe having a cooling mechanism, a first sample holder having a mechanism for retaining a sample in a cooled state, and a stage into which the microprobe and the first sample holder can be introduced, the method including cutting a bulk-shaped sample piece from the sample on the first sample holder retained in a cooled state; adhering the sample piece to a distal end of the microprobe that is cooled to a fixed temperature and transferring the sample piece to a second sample holder for thin film observation retained in a cooled state, which is different from the first sample holder, within a vacuum chamber of the charged particle beam device; separating the sample piece that has been transferred to the second sample holder from the microprobe and thin film processing the sample piece to a thickness that is less than the thickness during cutting; and observing the sample piece after the thin film processing.