Flexible Scatterometry Metrology System with Adjustable Optical Parameters
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Solution Overview
Problem
Existing scatterometry tools are limited in their application due to varying design specifications and requirements for different metrology applications, necessitating separate tools for thin film, critical dimension, and overlay metrology, which restricts their flexibility and efficiency.
Innovation Solution
A flexible scatterometry apparatus with adjustable optical parameters, including angle of incidence, azimuth, and numerical aperture, enabled by optical beam shaping and positioning elements, allowing for the same tool to perform multiple metrology types, such as thin film, critical dimension, and overlay metrology, with selective diffraction order detection and R-theta stage integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate scatterometry tools are used for different metrology applications (thin film, critical dimension, overlay), then measurement precision for each specific application is improved, but device complexity and the need for multiple devices increases
Solution Approach 1:
The scatterometry apparatus is designed with adjustable optical parameters including angle of incidence, numerical aperture, and azimuth angle capabilities that enable a single tool to perform multiple metrology functions (thin film, critical dimension, and overlay measurements) that previously required separate specialized tools, thereby reducing device complexity while maintaining measurement precision through parameter optimization for each application type
Solution Approach 2:
The apparatus incorporates dynamically adjustable optical parameters such as variable angle of incidence, adjustable numerical aperture, and rotatable azimuth angle capabilities that allow the system to adapt its configuration for different measurement types, enabling one device to replace multiple fixed-configuration tools while preserving the measurement precision required for each specific metrology application
2Measurement precision
If separate scatterometry tools are used for different metrology applications, then measurement accuracy for each application is optimized, but productivity decreases due to needing multiple devices
Solution Approach 1:
The scatterometry apparatus is designed with adjustable optical parameters including angle of incidence, numerical aperture, and azimuth angle capabilities that enable a single tool to perform multiple metrology functions (thin film, critical dimension, and overlay measurements) that previously required separate specialized tools, thereby reducing device complexity while maintaining measurement precision through parameter optimization for each application type
Solution Approach 2:
The apparatus merges previously separate measurement capabilities into a single integrated system by combining thin film, critical dimension, and overlay metrology functions with shared optical components and detection systems, allowing all measurement types to be performed on one device which improves productivity by eliminating the need to switch between multiple tools while maintaining the measurement accuracy required for each application
3Device complexity
If a single scatterometry tool is used for multiple metrology applications, then device complexity is reduced, but measurement precision may compromise due to varying design requirements
Solution Approach 1:
The apparatus incorporates dynamically adjustable optical parameters such as variable angle of incidence, adjustable numerical aperture, and rotatable azimuth angle capabilities that allow the system to adapt its configuration for different measurement types, enabling one device to replace multiple fixed-configuration tools while preserving the measurement precision required for each specific metrology application
Solution Approach 2:
The system employs parameter changes in the optical configuration including angle of incidence, numerical aperture, and azimuth angle to optimize measurements for different metrology applications. By dynamically adjusting these parameters, the single apparatus can achieve the measurement precision required for thin film, critical dimension, and overlay measurements without compromising accuracy despite the varying design requirements of each application type
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 efficient and flexible performance of various scatterometry measurements using a single tool, optimizing sensitivity and reducing the need for multiple devices, while enhancing measurement accuracy and reducing target size and measurement time.
Implementation Method 1
light scattered or diffracted by the surface to characterize and examine features of the surface
Implementation Method 2
a high numerical aperture objective lens system... the at least one illumination beam passes through the high numerical aperture objective lens system to impinge on a target site which generates a light scattering signal collected, in turn, by the objective lens system
Data Source
AI summary
A scatterometry tool including an illumination source for directing a light beam into a first optical beam shaping and positioning element at an illumination pupil plane of the tool where the light beam is modulated and directed to an objective lens system having a high numerical aperture. The objective receiving the modulated light beam and directing it onto a target to generate a scattering signal. The objective lens collects the scattering signal and directs it to a second optical beam shaping and positioning element at a collection pupil plane where the signal is modulated and then directed to detectors for receiving and processing the signal to determine surface characteristics of the target.