Flexible Substrate Topography Detection in Lithographic Apparatus
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Solution Overview
Problem
Lithographic processes face challenges in applying patterns to flexible substrates due to their susceptibility to out-of-plane deformation caused by contamination, surface flatness issues, and intermediate layer variations, making it difficult to maintain uniformity and achieve sub-micron feature sizes.
Innovation Solution
A method and apparatus that utilize electromagnetic radiation to detect the topography of flexible substrates, defining grid sections with specific exposure conditions and substrate positions to ensure each area is within a defined depth of focus, thereby compensating for non-uniformities and ensuring accurate pattern application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical lithography is applied to flexible substrates, then the technology can be used for flexible electronics and displays, but the flexible nature of substrates causes out-of-plane deformation making it difficult to maintain pattern quality
Solution Approach 1:
The system performs preliminary topography measurement of the flexible substrate surface before pattern application. By measuring the surface deformation in advance and storing this information, the system can compensate for the out-of-plane deformation when applying patterns, thereby maintaining pattern quality on flexible substrates
Solution Approach 2:
The system uses optical measurement to detect the actual topography of the flexible substrate surface and feeds this information back to the control system. The control system then adjusts the pattern application parameters based on this feedback to compensate for surface deformations and maintain manufacturing precision
2Ease of operation
If the substrate surface is not flat due to contamination or intermediate layer variations, then the flexible substrate can be used, but the depth of focus cannot be maintained across the entire substrate area
Solution Approach 1:
The substrate surface is divided into multiple measurement areas or zones. The topography is measured separately for each zone, and the focus parameters are adjusted independently for each zone based on its specific surface characteristics, allowing the system to maintain depth of focus uniformity across the entire flexible substrate
Solution Approach 2:
Instead of applying a uniform focus setting across the entire substrate, the system determines local topography characteristics for different areas and applies localized focus compensation. Each region receives customized exposure parameters tailored to its specific surface conditions, thereby maintaining manufacturing precision despite substrate flexibility
3Device complexity
If traditional lithography methods are used on flexible substrates, then the process can be simplified, but sub-micron feature sizes cannot be achieved due to substrate deformation
Solution Approach 1:
The system replaces mechanical substrate rigidity requirements with optical measurement and computational compensation. Instead of mechanically constraining the flexible substrate to maintain flatness, the system uses optical topography measurement and software-based focus adjustment to achieve sub-micron feature sizes on flexible, deformable surfaces
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 the accurate determination of substrate topography and adaptation of exposure conditions to maintain pattern quality across flexible substrates, addressing the challenges of non-uniformity and ensuring high-resolution pattern application.
Implementation Method 1
detecting changes in the intensity distribution, or angle of reflection, of the beam of radiation after the beam of radiation has been reflected from the surface of the substrate
Data Source
AI summary
A method of obtaining information indicative of the topography of a surface of a flexible substrate, the method including directing a beam of radiation at the surface of the flexible substrate; and detecting changes in intensity distribution, or angle of reflection, of the beam of radiation after the beam of radiation has been reflected from the surface of the substrate to obtain information indicative of the topography of the surface of the flexible substrate.