Adaptive Numerical Aperture Control for Wafer Metrology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for measuring structural and material characteristics of semiconductor wafers are inefficient, as they often require the same numerical aperture model for all wavelengths and iterations, leading to a trade-off between computation speed and accuracy.
Innovation Solution
A system and method that utilize different numerical aperture models for different wavelengths and iterations in electromagnetic simulations to model and measure wafer characteristics, allowing for a balance between computation speed and accuracy by selecting the appropriate model based on wavelength and iteration needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same numerical aperture model is used for all wavelengths and iterations, then the measurement process is simplified and easier to implement, but the computational efficiency and accuracy are compromised
Solution Approach 1:
The patent implements dynamic selection of numerical aperture models based on wavelength and iteration stage. The system automatically switches between different NA models (e.g., from higher-order to lower-order models) depending on the specific measurement conditions, making the system adaptive rather than static. This resolves the contradiction by enabling both ease of implementation through automation and computational efficiency through optimized model selection.
Solution Approach 2:
The patent changes the parameters of the numerical aperture model based on wavelength and iteration requirements. Different NA model parameters (such as the number of rays or polynomial order) are selected according to the specific measurement needs, allowing the system to optimize computational resources while maintaining accuracy where required.
2Measurement precision
If a high-accuracy numerical aperture model is used for all wavelengths and iterations, then measurement accuracy is improved, but computation time increases
Solution Approach 1:
The patent segments the measurement process into different stages (iterations) and wavelength ranges, applying different NA models to each segment. High-accuracy models are used only where necessary (e.g., in critical iterations or specific wavelength ranges), while lower-accuracy models are used in less critical segments. This segmentation resolves the contradiction by localizing high computational effort to only where it provides measurable benefit.
Solution Approach 2:
The patent applies high-accuracy NA models partially - only in specific iterations and wavelength ranges where they are most beneficial - rather than applying them excessively across the entire measurement process. This partial application maintains measurement accuracy where needed while avoiding the excessive computation time that would result from universal application of high-accuracy models.
3Productivity
If different numerical aperture models are used for different wavelengths and iterations, then computational efficiency and accuracy are optimized, but the system complexity increases
Solution Approach 1:
The patent implements feedback mechanisms that automatically determine which NA model to use based on measurement progress and wavelength information. The system monitors the measurement state and dynamically adjusts the NA model selection, providing intelligent control that manages complexity through automation rather than requiring complex manual configuration.
Solution Approach 2:
The measurement system performs self-service by automatically selecting appropriate NA models without external intervention. The system uses built-in logic to determine when to switch between different NA models based on wavelength and iteration stage, making the complexity management self-contained and reducing the burden on operators while maintaining computational efficiency.
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 improves the efficiency of wafer process control by optimizing computational speed and accuracy, enabling refined control over numerical aperture modeling in both spectral and temporal dimensions without sacrificing the quality of results.
Implementation Method 1
a metrology tool configured to obtain metrology data of a wafer
Implementation Method 2
The processor may be configured to perform a first electromagnetic simulation to model the metrology data at a first wavelength using a first numerical aperture model
Data Source
AI summary
Systems and methods for providing efficient modeling and measurement of critical dimensions and/or overlay registrations of wafers are disclosed. Efficiency is improved in both spectral dimension and temporal dimension. In the spectral dimension, efficiency can be improved by allowing different numerical aperture (NA) models to be used for different wavelengths in electromagnetic calculations, effectively providing a balance between computation speed and accuracy. In the temporal dimension, different NA models may be used at different iterations/stages in the process, effectively improving the computation speed without sacrificing the quality of the final result.