3D Reconstruction via Reference Marks in FIB-SEM Tomography
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Solution Overview
Problem
Current FIB-based tomographic methods face limitations in ease, speed, and efficiency of raw data collection, and lack robust data analysis and visualization methods for generating three-dimensional image data, particularly in scanning electron microscopy.
Innovation Solution
A method involving the use of two longitudinal marks on a sample surface with varying distance, where a charged particle beam system scans and removes slices perpendicular to the marks, recording image data and calculating slice thickness based on mark positions, enabling efficient generation of three-dimensional image data sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional FIB-based tomographic methods are used to collect volumetric image data, then three-dimensional reconstruction can be achieved, but the data collection process is time-consuming and requires specialized expertise for data reduction
Solution Approach 1:
The patent applies preliminary action by embedding reference marks and calibration structures into the sample before the FIB tomographic data collection begins. These pre-installed features enable automatic thickness measurement and image alignment during data reduction, eliminating the need for manual measurement of each slice and significantly accelerating the data processing workflow
Solution Approach 2:
The system implements self-service through automated image analysis algorithms that automatically measure slice thickness by detecting the reference marks in each SEM image, align images based on these marks, and perform 3D reconstruction without requiring specialized human expertise. The calibration structure self-corrects for sample tilting and stage drift, making the process robust and versatile
2Measurement precision
If perpendicular view measurement methods are used to quantify slice thickness, then accurate thickness measurement can be achieved, but additional image recording systems or sample movement is required
Solution Approach 1:
The patent solves the measurement problem by using an oblique viewing angle instead of a perpendicular view. Reference marks are deposited at a known angle relative to the sample surface, allowing slice thickness to be calculated from the apparent displacement of these marks in the SEM images. This geometric approach eliminates the need for additional perpendicular viewing systems while maintaining measurement accuracy
Solution Approach 2:
The reference marks serve as intermediaries between the FIB slicing process and the SEM imaging system. These marks provide a measurable geometric feature that links the physical slice thickness to the 2D image data, enabling thickness calculation without requiring direct perpendicular measurement of the slice itself
3Measurement precision
If manual measurement methods are used for each frame image, then slice thickness can be quantified, but the process requires specialized expertise and is time-consuming
Solution Approach 1:
The automated image analysis system performs self-service by automatically detecting reference marks, calculating slice thickness from mark displacement, and performing 3D reconstruction without human intervention. This eliminates the need for specialized expertise in data reduction while maintaining or improving measurement precision through consistent algorithmic application
Solution Approach 2:
The patent replaces manual mechanical measurement processes with automated computational methods. Instead of physically measuring each slice or manually analyzing images, computer algorithms automatically process the image data, detect reference marks, calculate thickness values, and perform 3D reconstruction, significantly improving ease of operation
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 significantly accelerates data acquisition, achieving higher resolution and accuracy in 3D data generation, reducing data collection time by a factor of five, and allowing for uniform image data without the need for sample movement, thus minimizing errors and enhancing the practicality of FIB-based nanotomography.
Implementation Method 1
removing a slice from said sample by a beam of charged particles scanning across said sample
Implementation Method 2
scanning said sample by a primary electron beam... and recording image data by detecting electrons emitted by said sample
Data Source
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AI summary
A method and an apparatus are for three-dimensional tomographic image generation in a scanning electron microscope system. At least two longitudinal marks are provided on the top surface of the sample which include an angle therebetween. In consecutive image recordings, the positions of these marks are determined and are used to quantify the slice thickness removed between consecutive image recordings.