EUV Lithography Mask Blank with Particle Trapping Coating
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Solution Overview
Problem
In EUV photolithography, contaminant particles reduce the yield of microelectronic devices by shielding mask patterns, and existing cleaning methods like vacuum and isopropyl alcohol/ethanol wipe-downs are not effective for maintaining cleanliness in critical components and routes through which masks pass, especially in delicate or small components.
Innovation Solution
A photomask with a modified surface or nano-fiber network coating that traps particulate matter, utilizing materials like carbon nanotubes, titanium oxide, or zinc oxide nanowires to enhance electron affinity and van der Waals interactions, forming a mesh structure to physically trap particles, and potentially modifying the surface to be more hydrophobic or hydrophilic for improved cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum and isopropyl alcohol/ethanol wipe-downs are used for cleaning, then some cleaning effect is achieved, but they are not effective for maintaining cleanliness in critical components and routes through which masks pass
Solution Approach 1:
The patent applies porous materials (nano-fiber networks with pore sizes of 1-100 nm) coated on mask surfaces to trap particulate contaminants. The porous structure allows particles to be captured within the network while maintaining optical transparency, effectively preventing contamination in critical mask areas where traditional cleaning methods fail.
Solution Approach 2:
The patent introduces a particle trapping layer as an intermediary between the mask surface and contaminants. This layer acts as a mediator that captures particles through physical trapping and electrostatic interactions, protecting the underlying mask structures without requiring direct contact cleaning that might damage delicate components.
2Manufacturing precision
If traditional cleaning methods are used, then the process is simple, but they cannot maintain ultra-clean surfaces critical for finer feature production
Solution Approach 1:
The patent applies particle trapping layers to masks before they are exposed to contaminants. This preliminary protective action prevents contamination accumulation during storage and handling, eliminating the need for complex cleaning systems while maintaining ultra-clean surfaces required for finer feature production.
Solution Approach 2:
The patent applies particle trapping layers selectively to critical areas of masks where contamination would most impact manufacturing precision. This localized application maintains surface cleanliness in critical regions without requiring complex system-wide cleaning solutions.
3Reliability
If masks are cleaned frequently to maintain cleanliness, then contamination is reduced, but productivity is lost due to cleaning time and potential damage to delicate components
Solution Approach 1:
The patent enables masks to self-trap and retain particles on their surfaces through the particle trapping layer. This self-service mechanism continuously maintains contamination control without requiring external cleaning interventions, keeping masks available for production and eliminating productivity loss associated with frequent cleaning cycles.
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
The solution effectively reduces particulate contamination on mask surfaces and in lithography tool routes, enhancing the cleanliness and yield of microelectronic devices by physically trapping particles, thus maintaining ultra-clean surfaces critical for finer feature production.
Implementation Method 1
utilizing materials like carbon nanotubes, titanium oxide, or zinc oxide nanowires to enhance electron affinity and van der Waals interactions, forming a mesh structure to physically trap particles
Implementation Method 2
utilizing materials like carbon nanotubes, titanium oxide, or zinc oxide nanowires to enhance electron affinity and van der Waals interactions
Data Source
AI summary
A mask for cleaning a lithography apparatus includes a mask substrate and a coating provided on a surface of the mask substrate. The coating is configured to trap particulate contaminant matter from the lithography apparatus. A method of cleaning a lithography tool is also provided preparing a cleaning mask including a particle trapping layer formed on a substrate. The method includes transferring the cleaning mask through a mask transferring route of the lithography tool. Subsequently, the method includes analyzing a particle trapped by the particle trapping layer.