Angled Probe for Planar TEM Sample Reorientation
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Solution Overview
Problem
Preparing planar view TEM samples for viewing in charged particle beam systems is challenging due to the need for reorientation of the sample, which requires a flip stage or removal from the vacuum chamber, complicating the thinning process and other analytical operations.
Innovation Solution
A method involving a probe with an angled shaft and tip is used to rotate the sample orientation precisely, allowing attachment to a TEM grid without reorienting the grid, enabling thinning and other processing within the system without a flip stage or vacuum chamber removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a planar view sample is extracted and attached to a TEM grid in a conventional FIB system, then the sample can be viewed in TEM, but the sample must be removed from the vacuum chamber and the grid reoriented to access the back side for thinning
Solution Approach 1:
The probe is designed with a rotatable shaft that can be dynamically reoriented during the thinning process. The shaft can rotate to present different surfaces of the attached sample to the ion beam, allowing thinning operations on the back side without removing the sample from the vacuum chamber or reorienting the TEM grid.
Solution Approach 2:
The probe serves as an intermediary device between the sample and the TEM grid. By attaching the sample to the probe rather than directly to the grid, the probe becomes a mediator that can be manipulated independently, allowing the sample orientation to be changed while the grid remains stationary in the vacuum chamber.
2Productivity
If a flip stage is used to reorient the TEM grid for back-side thinning, then thinning can be performed, but the process becomes more complex and time-consuming
Solution Approach 1:
The sample is preliminarily attached to the probe with the front surface facing the ion beam during extraction. The probe is designed in advance with an angled shaft and multi-faceted tip structure that enables subsequent rotation to present the back surface for thinning, eliminating the need for time-consuming flip stage operations.
Solution Approach 2:
The reorientation function is extracted from the TEM grid system and transferred to the independent probe. Instead of flipping the entire grid, only the probe needs to be rotated, which can be done quickly and independently without affecting the grid or requiring chamber manipulation.
3Ease of manufacture
If the sample is extracted with the front surface facing the ion beam, then extraction is efficient, but the back side cannot be accessed for thinning without removing the grid from the vacuum chamber
Solution Approach 1:
The probe shaft is designed at an angle (e.g., 45 degrees) relative to the tip surface, creating a dimensional relationship that allows rotation in one dimension (shaft rotation) to achieve orientation change in another dimension (sample surface presentation). This angular geometry enables the probe to present different sample surfaces to the ion beam by rotating the shaft to different angles.
Solution Approach 2:
The probe shaft can be dynamically rotated to different angles during the thinning process. The manipulator can rotate the shaft to present the front surface for extraction, then rotate it to a different angle to present the back surface for thinning, providing dynamic adaptability without removing the sample from the vacuum chamber.
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
Facilitates the preparation and thinning of planar view TEM samples within the charged particle beam system, enhancing sample processing efficiency and versatility for various analytical operations without the need for specialized stages or chamber reorientation.
Implementation Method 1
The sample, attached to the probe, is moved away from the substrate from which it was extracted and typically attached to a TEM grid using FIB deposition, static electricity, or an adhesive
Implementation Method 2
A probe comprising a shaft and having an angled tip is attached to the sample. By rotating the shaft through a first angle, the sample orientation is rotated by a second angle.
Data Source
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AI summary
A method and apparatus is described for orienting samples for charged particle beam operations. A sample is attached to a probe with a major surface of the sample at a non-normal angle to the probe shaft, and the probe shaft is rotated to reorient the sample. The invention is particularly useful for preparing planar view TEM samples. The invention allows for a sample to be mounted to a TEM grid and thinning by an ion beam without removing the grid from the vacuum chamber for reorienting. In one embodiment, a probe oriented at an angle, such as 45 degrees, to the sample stage has a probe tip with a flat area oriented parallel at 45 degrees to the probe axis, that is, the flat area is parallel to the sample stage. The flat area of the probe tip is attached to the sample, and when the probe is rotated 180 degrees, the orientation of the sample changes by 90 degrees, from horizontal to vertical. The sample can then be attached to a vertically oriented TEM grid on a sample stage. The sample stage is rotated and tilted to present the backside of the sample to the ion beam for thinning.