3D Hole Profile Measurement via Electron Energy Threshold Mapping
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Solution Overview
Problem
High aspect ratio holes with nanometric widths in integrated circuits are difficult to inspect accurately due to limited information provided by top images, which do not accurately represent the cross-sectional dimensions.
Innovation Solution
A method involving charging the vicinity of the hole, obtaining multiple electron images using a charged particle imager with varying electron energy thresholds, generating a mapping between height values and electron energy thresholds, and processing these images to provide three-dimensional measurements of the hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional top imaging methods are used to inspect high aspect ratio holes, then the inspection process is simple, but the measurement precision is insufficient due to limited information about cross-sectional dimensions
Solution Approach 1:
The patent transitions from two-dimensional top-down imaging to three-dimensional profiling by detecting electron energies from different height levels within the hole. This dimensional transformation enables accurate measurement of cross-sectional dimensions at multiple depths, resolving the limitation of traditional top imaging that only provides limited information about the hole structure.
Solution Approach 2:
The patent utilizes changes in electron energy parameters as electrons traverse different heights within the charged hole. By detecting electrons with varying energy levels and mapping them to corresponding height values, the system extracts detailed three-dimensional structural information, thereby achieving precise cross-sectional dimension measurement without requiring complex physical access to the hole.
2Measurement precision
If multiple electron images with different energy thresholds are obtained and processed, then three-dimensional measurement accuracy is improved, but the inspection time increases
Solution Approach 1:
The patent employs periodic acquisition of electron images at different energy thresholds to build the three-dimensional profile. By systematically varying the energy threshold and capturing images at discrete energy levels, the method efficiently constructs the height profile through mapped energy-to-height relationships, achieving accurate 3D measurement while maintaining reasonable inspection throughput.
3Area of moving object
If the hole width is reduced to nanometric dimensions, then the integration density is improved, but the difficulty of detecting and measuring the hole increases
Solution Approach 1:
The patent introduces charged particles (electrons) as an intermediary to probe the nanometric hole structure. By injecting electrons into the charged hole and detecting their energy distribution, the system indirectly measures the hole's three-dimensional profile without requiring direct physical contact or complex nanoscale imaging equipment, thereby enabling detection of nanometric features.
Solution Approach 2:
The patent replaces traditional mechanical or optical measurement systems with a charged particle-based detection method. Instead of using physical probes or optical microscopy that struggle at nanometric scales, the system uses electron energy detection to measure hole dimensions, achieving superior resolution and measurement capability for nanometric structures.
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 and efficient measurement of high aspect ratio holes by generating precise three-dimensional profiles, overcoming the limitations of traditional imaging methods that provide only limited information about the hole's cross-sectional dimensions.
Implementation Method 1
obtaining, by a charged particle imager, multiple electron images of the hole. Each electron image of the multiple electron images may be formed by sensing electrons of an electron energy that exceeds an electron energy threshold that is associated with the electron image
Implementation Method 2
Charging a vicinity of the hole
Data Source
AI summary
A system, computer program product and a method for measuring a hole. The method may include charging a vicinity of the hole having a nanometric width; obtaining, multiple electron images of the hole; wherein each electron image is formed by sensing electrons of an electron energy that exceeds an electron energy threshold that is associated with the electron image; wherein electron energy thresholds associated with different electron images of the multiple electron images differ from each other; receiving or generating a mapping between height values and the electron energy thresholds; processing the multiple electron images to provide hole measurements; and generating three dimensional measurements of the hole based on the mapping and the hole measurements.