EUV Collector Cooling via Semicircular Parallel Lines
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Solution Overview
Problem
Current grazing-incidence collectors (GICs) for extreme ultraviolet (EUV) lithography face significant thermal loads due to inefficient energy conversion, leading to optical distortion and potential damage, as existing cooling systems are not adequately developed for commercially viable EUV lithography systems.
Innovation Solution
A cooling system with spaced, semicircular cooling lines arranged in parallel planes perpendicular to the GIC shell's central axis, connected by input and output manifolds, which flow cooling fluid in two separate paths to maintain thermal equilibrium and reduce thermal gradients, enhancing thermal contact with a conformal metal layer and varying cooling line diameters to match thermal loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher EUV power is used to increase productivity, then the thermal load on the GIC increases, but this causes more optical distortion and potential damage to the GIC
Solution Approach 1:
The cooling system divides the GIC shell into multiple cooling zones with spaced-apart cooling lines arranged in parallel planes. Each cooling line operates independently with its own fluid flow path, allowing localized thermal management across different regions of the shell to handle the increased thermal load from higher EUV power.
Solution Approach 2:
The cooling lines are positioned at specific locations on the GIC shell back surface where thermal load is most intense. The system provides non-uniform cooling distribution matched to the thermal profile, with cooling capacity concentrated where needed most to prevent optical distortion while managing the overall thermal load.
2Device complexity
If conventional cooling systems are used, then the structure is simple, but they cannot effectively manage the substantial thermal load causing optical distortion
Solution Approach 1:
The cooling system transitions from conventional single-plane cooling to a multi-plane three-dimensional cooling architecture. Cooling lines are arranged in multiple parallel planes perpendicular to the shell axis, creating a volumetric cooling structure that more effectively removes heat from the GIC shell and maintains optical performance under substantial thermal load.
Solution Approach 2:
A conformal metal layer is applied between the cooling lines and the GIC shell back surface to enhance thermal contact. This intermediary layer improves heat transfer efficiency from the shell to the cooling fluid while maintaining the structural integrity and optical performance of the GIC.
3Temperature
If cooling lines are placed close together to improve cooling efficiency, then thermal management improves, but manufacturing difficulty increases
Solution Approach 1:
The cooling lines are pre-positioned and secured to the GIC shell back surface before final assembly. The spaced-apart arrangement in parallel planes allows for preliminary alignment and securing of each cooling line independently, simplifying the manufacturing process while maintaining effective thermal contact with the shell.
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 cooling system effectively manages thermal loads, minimizing optical distortion and ensuring the stability and performance of GICs by maintaining uniform temperature across the shell, thus preserving the focusing performance and extending the lifespan of the GICs.
Implementation Method 1
The cooling lines are in thermal contact with and run around a corresponding circumference of the back surface
Implementation Method 2
flow a cooling fluid from the input cooling-fluid manifold to the output cooling-fluid manifold over two paths for each cooling line
Data Source
AI summary
A cooling system (10) for an extreme ultraviolet (EUV) grazing incidence collector (GIC) mirror assembly (240) having at least one shell (20) with a back surface (22) is disclosed. The cooling system has a plurality of spaced apart circularly configured cooling lines (30) arranged in parallel planes (PL) that are perpendicular to the shell central axis (AC) and that are in thermal contact with and that run around the back surface. Input and output secondary cooling-fluid manifolds (44, 46) are respectively fluidly connected to the plurality of cooling lines to flow a cooling fluid from the input secondary cooling-fluid manifold to the output cooling secondary fluid manifold over two semicircular paths for each cooling line. Separating the cooling fluid input and output locations reduces thermal gradients that can cause local surface deformations in the shell that can lead to degraded focusing performance.