Ion Beam Sample Preparation with Feedback-Controlled Positioning
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Solution Overview
Problem
Ion beam milling for TEM sample preparation is inefficient due to difficulties in precisely positioning the sample of interest within the ion beam, leading to increased handling time, risk of sample damage, and suboptimal alignment for microscopy, which hampers the quality and efficiency of the process.
Innovation Solution
An ion beam sample preparation apparatus with multi-axis micro-positioning capabilities allows for adjustable tilt and rotation of the sample within the ion beam, enabling precise targeting and processing of regions of interest through image capture and feedback-controlled adjustments of the ion beam and sample stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sample is manually positioned and aligned in the ion beam system, then the region of interest can be targeted, but the process requires significant user time and effort with trial and error positioning
Solution Approach 1:
The system incorporates an imaging system that captures images of the sample region and provides real-time feedback to the control system. The control system processes these images and automatically adjusts the sample stage position and ion beam parameters based on the captured images, eliminating the need for manual trial-and-error positioning and significantly reducing user occupied time while maintaining high positioning precision.
Solution Approach 2:
The patent replaces manual mechanical positioning operations with an automated optical-mechanical system. The imaging system captures visual information about the sample, and the control system translates this information into precise mechanical adjustments of the sample stage and ion beam alignment, substituting human mechanical operations with an automated feedback-controlled system.
2Productivity
If the sample is handled multiple times for mounting and transferring, then preparation and analysis can proceed, but the delicate sample is at increased risk for damage
Solution Approach 1:
The patent combines multiple operations (ion beam milling, imaging, and sample positioning) into a single integrated vacuum chamber system. The sample remains on its holder throughout the entire preparation process, and all operations are performed without removing the sample from the chamber, thereby maintaining sample integrity while achieving complete preparation workflow.
Solution Approach 2:
The ion beam system is designed to perform multiple functions simultaneously or sequentially: it can mill the sample, image the sample region, and adjust sample positioning, all within the same vacuum environment. This multi-functionality eliminates the need to transfer the sample between different equipment, reducing handling steps and preserving sample integrity.
3Manufacturing precision
If the ion beam strikes the sample from multiple directions with sample rotation, then uniform milling is achieved, but it is difficult to position the specific region of interest at the center of rotation
Solution Approach 1:
The system employs dynamic control of both the sample stage and ion beam parameters. The sample stage can rotate to achieve uniform milling, while the ion beam parameters (current, voltage, angle) are dynamically adjusted in real-time based on feedback from the imaging system. This dynamic adjustment allows the system to maintain uniform milling while easily repositioning the region of interest at the beam center through automated stage movement and beam angle adjustment.
Solution Approach 2:
The control system changes multiple parameters simultaneously: sample stage position, stage rotation angle, ion beam current, ion beam voltage, and ion beam angle. These parameter changes are coordinated based on feedback from the imaging system, allowing the system to maintain optimal milling conditions while easily repositioning different regions of interest without manual intervention.
4Adaptability or versatility
If manual alignment and coordination of sample holder, rotation stage, and ion beam is performed, then the system can operate, but the complexity of coordinating multiple components increases
Solution Approach 1:
The imaging system provides continuous feedback about the sample position and the region of interest location. The control system uses this feedback to automatically coordinate the sample holder position, rotation stage orientation, and ion beam parameters, eliminating the need for manual alignment of these multiple components while maintaining full system adaptability.
Solution Approach 2:
The control system acts as an intermediary that receives input from the imaging system and automatically coordinates all mechanical and beam parameters. This intermediary control layer simplifies the overall system operation by managing the complexity of coordinating multiple components (sample holder, rotation stage, ion beam) through automated feedback control, while the system retains full configurability for different sample types and preparation 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 approach minimizes sample handling, improves precision in positioning the sample for efficient processing, and enhances the quality of the prepared samples by reducing the need for manual alignment and handling, thereby improving the overall efficiency and diagnostic imaging capabilities.
Implementation Method 1
The impact of ions on the sample will sputter material away from the area of ion impact
Implementation Method 2
the sample surface may be polished by the ion beam to a substantially smooth condition
Data Source
AI summary
Disclosed are embodiments of an ion beam sample preparation apparatus and methods. The methods operate on a sample disposed in a vacuum chamber and include steps of directing an intensity-controllable, tilt-angle controllable ion beam at a sample holder coupled to a rotation stage. The methods further include illuminating and capturing one or more images of the sample, extracting useful features from one or more images and thereafter adjusting the sample preparation steps. Further methods are disclosed for capturing sequences of images, programmatically rotating images, and displaying sequences of images with similar rotation angles. Further methods include extracting useful features from sequences of images that may change with respect to time as ion beam preparation continues.