Electron Beam Metrology Frame Correction for Feature Shrinkage
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Solution Overview
Problem
Current semiconductor examination processes face challenges in accurately measuring dimensions and detecting defects due to shrinkage of structural features caused by electron beam impingement during ultra-large-scale integration, which affects the precision and reliability of metrology data.
Innovation Solution
An electron beam examination system that generates corrected frames by determining spatial transformation data between reference and given frames, allowing for the creation of images that accurately represent structural features, thereby improving metrology data quality without requiring cumbersome modeling or prior knowledge of shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron beam examination is used to measure dimensions and detect defects, then examination capability is provided, but shrinkage of structural features occurs causing measurement inaccuracy
Solution Approach 1:
The system performs preliminary actions by acquiring multiple frames sequentially before final measurement, allowing detection of shrinkage effects over time. The reference frame is captured first, then subsequent frames are compared to it to identify and compensate for shrinkage-induced transformations, thereby preserving measurement accuracy despite the harmful shrinkage effect
Solution Approach 2:
The system implements feedback by determining spatial transformation data (Dshrinkage) that quantifies the shrinkage effect between frames. This feedback information is then used to generate corrected frames that compensate for the measured shrinkage, closing the loop between detection and correction to maintain reliable metrology data
2Measurement precision
If multiple frames are acquired to correct shrinkage effects, then measurement accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent replaces complex physical or manual correction methods with automated computational processing. The processor automatically determines spatial transformation data between frames and applies corrections algorithmically, substituting what would otherwise require cumbersome manual modeling or complex mechanical adjustment systems
Solution Approach 2:
The system changes parameters by determining spatial transformation data (Dshrinkage) that characterizes the shrinkage effect, then using this parameter to generate corrected frames. This parameter-based approach simplifies the correction process compared to comprehensive physical modeling, as it focuses on the specific transformation needed rather than all possible effects
3Productivity
If real-time correction is implemented during scanning, then productivity is improved, but processing requirements increase
Solution Approach 1:
The system performs preliminary frame acquisition and reference frame establishment during the scanning process itself, rather than after completion. This allows correction processing to begin early and proceed in parallel with remaining scanning operations, improving productivity without requiring excessive post-processing power
Solution Approach 2:
The system applies partial correction by focusing computational resources on determining the specific spatial transformation parameters (Dshrinkage) needed for correction, rather than performing complete physical modeling. This partial action approach provides sufficient correction for real-time application while keeping processing requirements manageable
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 enhances image quality and metrology data acquisition, providing robust and efficient process control even in tight process nodes like Extreme Ultraviolet Lithography, with real-time image correction during scanning.
Implementation Method 1
due at least to impingement of an electron beam of the electron beam examination system on the structural feature
Data Source
AI summary
There is provided a system and a method comprising obtaining a sequence of a plurality of frames of an area of a specimen, wherein at least one frame of the sequence is transformed with respect to another frame, obtaining a reference frame based at least on a first frame of the sequence, determining, based on the reference frame, a reference pattern, wherein the reference pattern is informative of a structural feature of the specimen in the area, for a given frame of the sequence, determining, based on the given frame, a pattern informative of said structural feature in the area, determining data Dshrinkage informative of an amplitude of a spatial transformation between the reference pattern and the pattern, generating a corrected frame based on said pattern and Dshrinkage and generating an image of the area.