3D Structural Evaluation Using Multi-Angle Electron Scattering
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Solution Overview
Problem
Current methods for evaluating structural elements of nanometric dimensions on specimens, such as semiconductor wafers, are limited by their destructive nature and inability to provide accurate, non-destructive three-dimensional information due to obscured parts and complex shapes.
Innovation Solution
A method involving the illumination of structural elements with electron beams of different incidence angles, detection of forward scattered electrons, and generation of three-dimensional information using spatial and energy filtering to isolate and reconstruct obscured features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If destructive methods such as TEM or STEM are used to obtain three dimensional information, then measurement precision is improved, but the specimen is damaged and the method is not suitable for routine evaluation
Solution Approach 1:
The patent creates a three-dimensional model (copy) of the structural elements based on scattered electron signal intensities from multiple imaging directions, rather than physically sectioning the specimen. This virtual reconstruction provides accurate 3D information while preserving the original specimen integrity.
Solution Approach 2:
The patent replaces the mechanical sectioning process of TEM/STEM with an optical/electronic imaging system that uses scattered electron detection and computational reconstruction. This substitution eliminates the need for physical specimen preparation and damage while achieving 3D visualization.
2Ease of operation
If structural elements are evaluated from a single viewing direction, then the evaluation process is simple, but obscured parts and complex shapes cannot be fully visualized
Solution Approach 1:
The patent segments the imaging process into multiple discrete viewing directions (e.g., 0°, 45°, 90°, 135°), capturing scattered electron signals from each angle separately. This segmentation allows comprehensive visualization of all structural elements without obscuration, while the computational reconstruction integrates these segments into a unified 3D model.
Solution Approach 2:
The patent transitions from two-dimensional single-direction imaging to three-dimensional reconstruction by adding the angular dimension. By collecting data from multiple viewing angles and reconstructing in 3D space, the system recovers information from obscured parts that would be invisible in any single 2D projection.
3Measurement precision
If electron beams of multiple incidence angles are used to illuminate structural elements, then three dimensional information accuracy is improved, but device complexity increases
Solution Approach 1:
The patent employs a single scattered electron detector that serves multiple functions: detecting scattered electrons from all imaging directions and capturing signals from all structural elements regardless of viewing angle. This multi-functional detector simplifies the overall system compared to having separate detection systems for each angle.
Solution Approach 2:
The patent uses the specimen's own scattered electron signals, which naturally occur when electron beams interact with the structural elements. By detecting these self-generated scattered electrons from multiple angles and reconstructing the 3D model, the system eliminates the need for external labeling, contrast agents, or complex sample preparation procedures.
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
Enables accurate, non-destructive three-dimensional evaluation of structural elements, providing detailed models of both visible and obscured parts, while minimizing beam interaction and widening, thus preserving specimen integrity.
Implementation Method 1
detecting forward scattered electrons that are scattered from the structural elements
Data Source
AI summary
A method, a non-transitory computer readable medium and a three-dimensional evaluation system for providing three dimensional information regarding structural elements of a specimen. The method can include illuminating the structural elements with electron beams of different incidence angles, where the electron beams pass through the structural elements and the structural elements are of nanometric dimensions; detecting forward scattered electrons that are scattered from the structural elements to provide detected forward scattered electrons; and generating the three dimensional information regarding structural elements based at least on the detected forward scattered electrons.