EUV Aperture Cooling for Stable Plasma Generation
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Solution Overview
Problem
EUV radiation source devices of the DPP type face challenges with discharge electrode wear and instability due to thermal load, leading to reduced lifetime and unstable EUV radiation generation, and existing solutions require large and complex pumping and debris trap systems to maintain pressure differences.
Innovation Solution
The EUV radiation source device incorporates an aperture component with a cooling system between the discharge and collector optics, allowing for reduced opening diameter and simplified pressure management, using a partition to separate the discharge and collector spaces and employing a gas curtain and foil trap for debris mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the aperture diameter is reduced to simplify pressure management, then the pumping system size is reduced, but the EUV radiation transmission may be insufficient
Solution Approach 1:
The patent changes the physical state of the aperture component by introducing active cooling, transforming it from a thermal equilibrium component to one that actively manages heat dissipation. This allows the aperture to be positioned closer to the plasma source without thermal damage, thereby reducing the aperture diameter while maintaining sufficient EUV radiation transmission through optimized geometric parameters.
Solution Approach 2:
The aperture component transitions from a static thermal component to a dynamically cooled component with active thermal management. The cooling system enables the aperture to operate in a non-equilibrium thermal state, allowing reduced dimensions while maintaining structural integrity and radiation transmission properties.
2Device complexity
If the discharge electrodes are not cooled, then the structure is simpler, but the electrode lifetime is reduced due to thermal wear
Solution Approach 1:
The patent applies active cooling to the discharge electrodes, changing their thermal state from uncontrolled heating to actively managed temperature. This parameter change extends electrode lifetime by preventing thermal wear and degradation, allowing the electrodes to operate sustainably under high power discharge conditions.
Solution Approach 2:
The cooling system performs preliminary thermal management on the discharge electrodes before excessive heat accumulation occurs. By continuously removing heat during operation, the system prevents thermal wear and extends electrode lifetime, addressing the thermal management issue before it leads to component failure.
3Device complexity
If the aperture component is not cooled, then the structure is simpler, but it cannot be positioned close to the plasma source
Solution Approach 1:
The aperture component is transformed from a passive thermal component to an actively cooled component. This parameter change enables the aperture to withstand thermal environments closer to the plasma source, reducing the distance between the aperture and plasma source while maintaining component integrity through active thermal management.
Solution Approach 2:
The aperture component transitions to a dynamically cooled state, allowing it to operate in proximity to the high-temperature plasma source. The active cooling system enables the aperture to maintain structural integrity at reduced distances from the plasma, optimizing the optical path while managing thermal loads.
4Device complexity
If no cooling system is implemented, then the device is simpler, but metallic debris damages the collector optics
Solution Approach 1:
The cooling system performs preliminary thermal management on the discharge electrodes and aperture component, preventing excessive heat accumulation that would lead to material degradation and metallic debris formation. By maintaining controlled temperatures, the system prevents the generation of harmful debris before it can damage the collector optics.
Solution Approach 2:
The implementation of active cooling changes the thermal parameters of the discharge electrodes and aperture component, preventing thermal wear and material degradation. This parameter change reduces the generation of metallic debris, thereby protecting the collector optics from damage without requiring additional debris removal systems.
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 extends the lifetime of discharge electrodes, reduces the size and complexity of pumping and debris trap systems, and maintains desired pressure differences, ensuring stable EUV radiation generation and reduced damage to collector optics.
Implementation Method 1
there is a device for cooling this aperture component
Implementation Method 2
a high density and high temperature plasma is produced by the vaporized fuel being heated and excited by a discharge which forms between the electrodes
Implementation Method 3
a discharge which forms between the electrodes
Implementation Method 4
EUV radiation which is emitted from a high density and high temperature plasma
Data Source
AI summary
An EUV radiation source device with a chamber that is divided into a discharge space and a collector mirror space provided with EUV collector optics. Between them, an aperture component with an opening which is cooled is provided. First and second discharge electrodes are rotated. Sn or Li is irradiated with a laser. Pulsed power is applied between the first and second discharge electrodes to form a high density and high temperature plasma between the two electrodes so that EUV radiation with a wavelength of 13.5 nm is emitted, is focused by the EUV collector optics and is guided into the irradiation optical system of an exposure tool. There are a first pumping device and a second pumping device for pumping the discharge space and the collector mirror space. The discharge space is kept at a few Pa, and the collector mirror space is kept at a few 100 Pa.