Faceted EUV Collector Mirror for Debris Mitigation
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Solution Overview
Problem
Existing EUV light source systems face challenges in maintaining a uniform gas flow parallel to the collector surface, which is essential for effective debris mitigation and surface protection, as conventional gas delivery systems struggle to maintain flow across the entire collector surface without compromising reflectivity.
Innovation Solution
A reflective EUV optic is configured with an ensemble of facets spaced apart to form gaps, allowing for parallel gas flow across the collector surface, with the facets being offset in the vertical direction to minimize reflective area loss and ensure uniform gas distribution, and a plenum in fluid communication with these gaps to direct gas tangentially past the reflective surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a continuous gas flow is used to protect the collector surface, then debris mitigation is improved, but gas distribution uniformity deteriorates
Solution Approach 1:
The collector surface is divided into multiple zones with dedicated gas inlet ports distributed across different regions. Each inlet port supplies gas to a specific zone, ensuring uniform gas distribution across the entire collector surface while maintaining continuous protection against debris.
Solution Approach 2:
Gas inlet ports are strategically positioned at different locations on the collector surface, with each port providing localized gas flow to its adjacent region. This local gas supply approach ensures that each area receives adequate protection while maintaining overall uniformity across the collector.
2Object-affected harmful factors
If gas flow is increased to improve debris protection, then debris mitigation is improved, but reflectivity deteriorates due to non-uniform distribution
Solution Approach 1:
The gas delivery system is segmented into multiple independent inlet ports distributed across the collector surface. This segmentation allows each port to supply gas at optimized flow rates to its local region, achieving adequate debris protection across the entire surface without excessive gas flow that would compromise reflectivity.
Solution Approach 2:
Each region of the collector surface receives gas flow tailored to its specific needs through locally positioned inlet ports. This localized gas supply ensures that sufficient protection is provided where needed while avoiding non-uniform gas distribution that would reduce reflectivity in other areas.
3Stability of the object's composition
If gas inlet ports are positioned to maximize coverage, then gas distribution uniformity is improved, but reflective area is reduced
Solution Approach 1:
Gas inlet ports are positioned at the periphery or edges of the collector surface, where they can effectively supply gas to adjacent regions without occupying significant reflective area. This peripheral positioning strategy maintains gas distribution uniformity while minimizing impact on the reflective surface area.
Solution Approach 2:
The gas inlet ports are positioned in the peripheral region of the collector surface, utilizing the edge areas that would otherwise be non-reflective or less critical for reflection. This dimensional placement strategy allows gas distribution uniformity to be achieved without sacrificing the central reflective area needed for optimal performance.
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 configuration effectively creates a uniform gas sheath parallel to the collector surface, protecting it from debris and maintaining reflectivity by ensuring efficient gas flow and distribution, thereby enhancing the performance of EUV light source systems.
Implementation Method 1
H2 gas is introduced into the vacuum chamber to decelerate the energetic debris (ions, atoms, and clusters) of target material created by the plasma. The debris is decelerated by collisions with the gas molecules. For this purpose a flow of H2 gas counter to the debris trajectory is used.
Implementation Method 2
A reflective EUV optic is configured with an ensemble of facets spaced apart to form gaps, allowing for parallel gas flow across the collector surface, with the facets being offset in the vertical direction to minimize reflective area loss and ensure uniform gas distribution, and a plenum in fluid communication with these gaps to direct gas tangentially past the reflective surface.
Implementation Method 3
The H2 gas may be dissociated into hydrogen radicals H*. The hydrogen radicals H* in turn help to remove target material deposits from the collector surface. For example, in the case of tin as the target material, the hydrogen radicals participate in reactions on the collector surface that lead to the formation of volatile gaseous stannane (SnH4) which can be pumped away.
Data Source
AI summary
A reflective EUV optic such as a collector mirror configured as an array of facets that are spaced apart to form respective gaps between adjacent facets. The gaps are used as inlets for gas flow across one of the facets such that flow is introduced parallel to the optic surface. The facets can be made with offsets such that loss of reflective area of the EUV optic can be minimized. The gas facilitates removal of target material from the surface of the facets.