Focused Beam Scatterometry for Submicron Structure Characterization
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Solution Overview
Problem
Current metrology techniques face challenges in accurately measuring submicron structures and thin films in microelectronic devices due to the limitations of simple imaging as sample structure dimensions approach or exceed light wavelengths, requiring non-destructive, high-throughput, and high-accuracy methods for characterization.
Innovation Solution
A focused beam scatterometry system utilizing coherent light sources, polarizers, compensators, and detectors to measure the intensity and polarization state of light scattered from periodic structures, allowing for simultaneous multi-angle measurements and avoiding the complexity of decoupling polarization and azimuthal angle variables, with a focusing optic providing a wide range of incidence angles and azimuthal orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple imaging such as microscopy is used, then the measurement process is simple, but measurement precision deteriorates when sample structure dimensions become smaller than or comparable to light wavelength
Solution Approach 1:
The patent replaces simple optical imaging with scatterometry, which analyzes the intensity and polarization state of light scattered off the sample structure. This substitution enables measurement of submicron structures by using diffraction patterns and polarization changes rather than direct imaging, overcoming the wavelength limitation while maintaining operational feasibility through automated measurement systems.
2Measurement precision
If multiple measurement techniques are combined, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines multiple measurement capabilities within a single scatterometry system, including intensity measurement, polarization state measurement, and multi-angle measurement. By merging these functions into one integrated system rather than requiring separate instruments, the patent achieves high measurement precision for both submicron structure dimensions and thin film thicknesses while managing system complexity through unified instrumentation.
3Measurement precision
If focused beam scatterometry is used, then measurement precision and sensitivity improve, but measurement time increases
Solution Approach 1:
The patent implements continuous measurement through automated sample stage movement and sequential measurement cycles. The system continuously scans through multiple angles and polarization states without interruption, maintaining productive measurement action throughout the process. This continuous operation, combined with automated data collection and processing, reduces idle time while preserving the high precision and sensitivity required for submicron structure characterization.
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 precise characterization of submicron structure dimensions and thin film thicknesses with improved sensitivity and accuracy, simplifying the measurement process by maintaining uniform polarization state over a range of azimuthal angles, thus facilitating more reliable data interpretation and model predictions.
Implementation Method 1
coherent light sources
Implementation Method 2
focusing optic providing a wide range of incidence angles
Implementation Method 3
polarizers, compensators, and detectors to measure the intensity and polarization state of light scattered from periodic structures
Implementation Method 4
measure the intensity and polarization state of light scattered from periodic structures
Data Source
AI summary
A system for monitoring thin-film fabrication processes is herein disclosed. Diffraction of incident light is measured and the results are compared to a predictive model based on at least one idealized or nominal structure. The model and/or the measurement of diffracted incident light may be modified using the output of one or more additional metrology systems.