Semiconductor e-Beam Image Registration for Charging Artifact Reduction
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Solution Overview
Problem
Current semiconductor inspection methods using electron beam tools face challenges with image artifacts due to charging effects, leading to inaccuracies in critical dimension measurements, especially as feature sizes shrink, causing scanning faults and distortion.
Innovation Solution
A computerized system with processing and memory circuitry that registers and combines frames acquired from multiple directions to generate images, reducing image artifacts by correcting for drifts and offsets caused by charging effects and other physical phenomena, using techniques like pattern matching and synchronization adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron beam tools scan the semiconductor specimen from multiple directions to reduce image artifacts, then measurement precision is improved, but device complexity increases due to the need for frame registration and synchronization mechanisms
Solution Approach 1:
The system performs preliminary synchronization between the scanning process and imaging process before actual inspection. Time synchronization signals are generated in advance to coordinate the electron beam scanning with frame capture, ensuring that frames from multiple directions are properly aligned without requiring complex post-processing registration operations.
Solution Approach 2:
A time synchronization signal acts as an intermediary between the scanning control system and the imaging system. This synchronization signal mediates the coordination between electron beam deflection and frame capture timing, enabling accurate temporal alignment of multi-directional scans without direct complex interaction between the subsystems.
2Manufacturing precision
If the scanning process is synchronized with the imaging process to correct drifts, then manufacturing precision is improved, but loss of time occurs due to synchronization adjustments and processing delays
Solution Approach 1:
The synchronization process operates continuously throughout the scanning and imaging operations rather than as discrete correction steps. The time synchronization signal is generated continuously to maintain ongoing coordination between scanning and imaging, eliminating the need for stop-and-correct cycles that would cause time losses.
Solution Approach 2:
The system replaces mechanical drift correction mechanisms with a temporal synchronization approach. Instead of physically adjusting or repositioning components to correct drifts, the system uses time-synchronized signal processing to computationally align frames, reducing mechanical intervention time and processing delays.
3Reliability
If frames are acquired sequentially from multiple directions, then image artifacts are reduced through combining registered frames, but productivity decreases due to multiple scanning passes
Solution Approach 1:
The system implements periodic multi-directional scanning cycles where frames are acquired from different directions in a repeating sequence. This periodic acquisition pattern allows systematic collection of multi-angle data while maintaining a steady inspection rhythm, balancing the need for multiple passes with efficient throughput by establishing a predictable scan cycle.
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
The system produces images with reduced artifacts, improving the accuracy and reliability of semiconductor inspections, enabling more precise critical dimension measurements and defect detection.
Implementation Method 1
obtain a sequence of frames of an area of the semiconductor specimen, the sequence of frames being acquired by an electron beam tool configured to scan the area from a plurality of directions
Implementation Method 2
correcting for drifts and offsets caused by charging effects and other physical phenomena
Data Source
AI summary
There is provided a system and method of examination of a semiconductor specimen, comprising: obtaining a sequence of frames of an area of the specimen acquired by an electron beam tool configured to scan the area from a plurality of directions, the sequence comprising a plurality of sets of frames each acquired from a respective direction; and registering the plurality of sets of frames and generating an image of the specimen based on result of the registration, comprising: performing, for each direction, a first registration among the set of frames acquired therefrom, and combining the registered set of frames to generate a first composite frame, giving rise to a plurality of first composite frames respectively corresponding to the plurality of directions; and performing a second registration among the plurality of first composite frames, and combining the registered plurality of first composite frames to generate the image of the specimen.