Imprint Lithography Substrate Contamination Detection
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Solution Overview
Problem
Current methods for detecting substrate contamination in imprint lithography are expensive, time-consuming, and often inconclusive, leading to defects and voids in the formed layer due to surface contamination, particularly organic contaminants.
Innovation Solution
A method involving the detection of periodically occurring nanovoids in an imprinted layer using light scattering techniques and Fourier transform analysis, along with a system for cleaning and storing substrates in a filtered environment to reduce contamination, including the use of chemical filters to remove organic contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct analysis methods (GC-MS, TOF-SIMS) are used to detect substrate surface contamination, then measurement precision is improved, but loss of time and cost increase significantly
Solution Approach 1:
The patent replaces complex mechanical/chemical analysis systems (GC-MS, TOF-SIMS) with an optical detection system using light scattering and FFT analysis. This substitution maintains measurement precision for contamination detection while dramatically reducing detection time and cost, as the optical system provides rapid non-contact measurement without the time-consuming sample preparation and analysis steps of traditional methods
Solution Approach 2:
The patent creates an optical copy or representation of the contamination effects through light scattering patterns. Instead of directly analyzing the chemical composition of contaminants, the system captures the scattering signature that replicates the contamination information, enabling rapid detection through FFT analysis of the scattered light distribution
2Measurement precision
If direct analysis methods (GC-MS, TOF-SIMS) are used to detect substrate surface contamination, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex chemical analysis instrumentation (GC-MS, TOF-SIMS) with a relatively simple optical system consisting of a light source, detector, and FFT analysis capability. This substitution maintains the ability to detect contamination with high precision while dramatically simplifying the device architecture and reducing operational complexity
Solution Approach 2:
The patent uses light scattering patterns as an optical copy of the contamination state. Instead of requiring complex chemical analysis equipment to directly identify contaminants, the system captures the scattering signature that replicates contamination information, which can then be analyzed through relatively simple FFT processing
3Ease of operation
If substrates are stored in unfiltered environments, then ease of operation is improved, but surface contamination increases leading to defects
Solution Approach 1:
The patent creates a controlled atmosphere environment for substrate storage using filtered air with specific particle and chemical contamination limits. This inert-like environment protects substrates from contamination during storage and handling, preventing the formation of nanovoids while maintaining ease of operation through standardized cleanroom practices
Solution Approach 2:
The patent applies different quality levels of environmental control to different areas or stages of substrate handling. By establishing specific contamination thresholds for storage environments and using targeted cleaning procedures, the system provides localized quality control that prevents contamination where critical while maintaining operational 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 allows for fast, precise detection of substrate contamination levels and reduces surface contamination, improving the quality and reproducibility of imprint lithography by correlating nanovoid defects with contamination levels and maintaining cleanliness through controlled storage and handling environments.
Implementation Method 1
contacting the polymerizable material with a planar imprint template, polymerizing the polymerizable material to form an imprint layer on the substrate
Implementation Method 2
The detection of substrate defects can use light scattering techniques, and further include generating a scatter map of the substrate
Implementation Method 3
the analysis of the detected defects can included performing a Fourier transform (FFT) analysis of the scatter map
Implementation Method 4
storing the cleaned substrate in a sealed environment filtered by a chemical filter suitable for removing organic contaminants from air. Exemplary chemical filters include carbon filters
Implementation Method 5
the sealed environment can also be filtered by a high efficiency particle air (HEPA) filter to protect against particulate contaminants
Data Source
AI summary
Detection of periodically repeating nanovoids is indicative of levels of substrate contamination and may aid in reduction of contaminants on substrates. Systems and methods for detecting nanovoids, in addition to, systems and methods for cleaning and/or maintaining cleanliness of substrates are described.