EUV Collector Mirror Cooling Channel Design
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Solution Overview
Problem
The collector performance of EUV light source devices deteriorates due to heat deformation of the collector mirror assembly, leading to reduced light source output and intensity homogeneity, as existing cooling methods cannot completely suppress temperature rises across the reflective shells.
Innovation Solution
The cooling channel is positioned along the generatrix direction of the reflective shells and the holding structure, using molybdenum as the base material for the reflective shells to enhance cooling efficiency and reduce heat deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods are used for the collector mirror assembly, then some temperature reduction is achieved, but heat deformation still occurs causing collector performance deterioration
Solution Approach 1:
The cooling channels are strategically positioned at specific locations on the reflective shells where heat accumulation most affects performance. The generatrix direction cooling channels are placed to target areas where heat deformation causes maximum collector performance deterioration, providing localized cooling where it is most needed rather than uniform cooling throughout the entire assembly.
Solution Approach 2:
Cooling channels are introduced in the generatrix direction (along the length of the ellipsoidal shells) in addition to or instead of conventional circumferential cooling. This adds a new dimensional approach to heat removal, addressing thermal gradients that extend along the longitudinal axis of the mirrors and preventing heat deformation that conventional cooling methods cannot address.
2Temperature
If cooling channels are added to the collector mirror assembly, then temperature control improves, but device complexity increases
Solution Approach 1:
The cooling channels serve multiple functions simultaneously: they remove heat from the reflective shells, provide structural support within the mirror assembly, and maintain the precise geometric relationships between multiple shells. By integrating these functions into a single cooling system design, the patent avoids the need for separate cooling and support structures, thereby reducing overall device complexity.
Solution Approach 2:
The cooling channel structure is merged with the holding structure that supports the reflective shells. The same structural components that hold the shells in place also contain the cooling channels, eliminating the need for separate cooling infrastructure and simplifying the overall device architecture while maintaining effective temperature control.
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 suppresses heat distortion and deformation, maintaining collector performance by efficiently cooling the reflective shells and holding structure, ensuring stable EUV radiation output and angular distribution.
Implementation Method 1
a cooling channel through which a cooling medium for cooling the reflective shell passes
Implementation Method 2
efficiently cooling the reflective shells and holding structure
Implementation Method 3
a reflective layer reflecting extreme ultraviolet radiation
Implementation Method 4
generate a high temperature plasma by heating and exciting an EUV radiation seed and to extract the EUV radiation which is emitted from this plasma
Data Source
AI summary
A deterioration of the collector performance in an extreme ultraviolet light source device due to a heat deformation of the collector mirror assembly is to be prevented. The collector mirror assembly used in the extreme ultraviolet light source device comprises a plurality of reflective shells 21 with different diameters which are shaped as ellipsoids of revolution or hyperboloids of revolution, wherein the reflective shells 21 are arranged in a nested shape and the ends thereof are held by a holding structure 22. A cooling channel, through which a cooling medium flows is mounted at the reflective shell 21 in the axial direction of the reflective shell on the face being the back side of the reflective surface. This cooling channel acts as a reinforcement material and is able to suppress a heat deformation of the reflective shell 21. By using molybdenum as the material for the reflective shells 21, the heat deformation can be suppressed even further, and by providing cooling channels in the holding structure 22, the collector mirror assembly can be cooled even more efficiently and a heat deformation thereof can be suppressed.