Sample Height Regulation Using Dual Beam Secondary Electron Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for regulating the sample stage height in FIB-SEM apparatuses are inefficient and imprecise, especially with large diameter wafers, leading to reduced operational efficiency and precision due to the need for inclining the sample and frequent stage displacement, which worsens with sample bending.
Innovation Solution
A method involving the use of two charged particle beams (electron and ion beams) to calculate and adjust the sample stage height based on secondary electron images from different angles, ensuring both beams focus on the same observation point without inclining the sample stage, allowing precise and efficient observation and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sample stage is inclined to regulate height, then the focused ion beam and electron beam can be focused on the same observation point, but the operation efficiency is lowered and the process becomes more complex
Solution Approach 1:
Instead of inclining the sample stage to achieve focus alignment, the patent inverts the approach by keeping the sample stage horizontal and adjusting the height position based on calculations from secondary electron images. This eliminates the need for sample inclination while maintaining focus precision.
Solution Approach 2:
The patent replaces the mechanical inclination mechanism with a calculation-based height adjustment system. By computing the required height from image data and automatically adjusting the stage height, the system substitutes complex mechanical tilting with simpler vertical positioning.
2Manufacturing precision
If the sample stage is inclined for height regulation, then beam focus alignment is achieved, but the device complexity increases due to additional adjustment mechanisms
Solution Approach 1:
The patent replaces mechanical inclination mechanisms with a calculation-based system that uses secondary electron images to determine the required sample height. This substitutes complex mechanical tilting apparatus with simpler vertical height adjustment controlled by computational algorithms.
Solution Approach 2:
The patent introduces secondary electron images as an intermediary to bridge the gap between sample position and beam focus alignment. By using image-based calculations as a mediator, the system avoids direct mechanical coupling between stage inclination and focus control.
3Reliability
If frequent sample stage displacement is performed to accommodate sample bending, then observation and processing can continue, but the throughput is reduced
Solution Approach 1:
The patent performs preliminary height calculation using secondary electron images before observation and processing begin. By pre-determining the correct sample height position, the system eliminates the need for frequent interruptions and stage displacements during the workflow, thereby maintaining throughput.
Solution Approach 2:
The patent implements a feedback mechanism where secondary electron images are used to calculate and verify the correct sample height. This feedback loop ensures that the sample is positioned accurately at the beginning, reducing the need for corrective displacements and maintaining continuous operation.
4Ease of operation
If the sample height is not precisely regulated, then the operation is simpler, but the observation precision and processing accuracy deteriorate
Solution Approach 1:
The patent enables the system to self-regulate sample height automatically using secondary electron images and calculation algorithms. The system determines and adjusts its own height position without requiring manual intervention, maintaining both simplicity and precision.
Solution Approach 2:
The patent replaces manual height adjustment mechanisms with an automated calculation system based on secondary electron images. This substitution maintains operational simplicity while achieving precise height regulation through computational methods.
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 precise and efficient observation and processing without inclining the sample stage, even with bent samples, by calculating the required sample height from secondary electron images, improving throughput and precision, and allowing automated processing across multiple positions.
Implementation Method 1
scan-irradiating an area including an observation point on a sample with a first charged particle beam to obtain a first secondary electron image including the observation point
Data Source
AI summary
In a sample height regulating method, an area including the observation point on the sample is scan-irradiated with a first charged particle beam to obtain a first secondary electron image including the observation point. An area including the observation point on the sample is then scan-irradiated with a second charged particle beam to obtain a second secondary electron image including the observation point. Thereafter, based on magnifications of the first secondary electron image and the second secondary electron image and a distance between the observation point in the first secondary electron image and the observation point in the second secondary electron image, a height of the sample required for focusing the first charged particle beam and the second charged particle beam on the observation point is calculated. A sample stage supporting the sample is then displaced so as to position the sample at the calculated sample height.