EUV Source-Collector Device with Contaminant Trap
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Solution Overview
Problem
Current EUV sources for lithographic applications face challenges in increasing useful power and effectively mitigating particulate contaminants, which affect the efficiency and reliability of radiation generation and collection.
Innovation Solution
A source-collector device comprising a target unit for plasma-forming material, a laser unit to generate a plasma, a contaminant trap to reduce particulate contaminants, a radiation collector with grazing-incidence reflectors, and a filter to attenuate specific wavelength ranges, enhancing radiation collection and power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plasma source is used to generate EUV radiation, then the useful power of the source can be increased, but particulate contaminants are generated that affect efficiency and reliability
Solution Approach 1:
The source-collector device is divided into distinct functional zones: a plasma generation region, a contaminant trap region, and a radiation collection region. This segmentation allows the plasma to be generated for high power output while the contaminant trap selectively removes particulate contaminants before radiation reaches the collector, resolving the contradiction between power generation and contaminant mitigation.
Solution Approach 2:
A contaminant trap is introduced to extract and remove particulate contaminants from the plasma environment before the radiation reaches the collector. This extraction mechanism separates the harmful particulate matter from the useful radiation, allowing high power plasma generation while maintaining collector efficiency and reliability through continuous contaminant removal.
2Loss of energy
If conventional radiation collection methods are used, then the device structure is simpler, but radiation collection efficiency and power efficiency are reduced
Solution Approach 1:
The source-collector device employs dynamic elements including a rotating wheel with liquid metal supply that continuously replenishes plasma-forming material, and a controllable contaminant trap that can be rotated into or out of the radiation path. These dynamic components optimize radiation collection efficiency and power efficiency while managing complexity through controlled motion rather than static complex structures.
Solution Approach 2:
A contaminant trap acts as an intermediary element positioned between the plasma source and the radiation collector. This mediator selectively removes particulate contaminants while allowing EUV radiation to pass through, thereby improving power efficiency and radiation collection efficiency without requiring fundamental changes to the overall device structure.
3Manufacturing precision
If the target surface minimum dimension is reduced to increase precision, then manufacturing precision improves, but plasma formation and radiation collection efficiency decrease
Solution Approach 1:
The device uses a liquid metal target system where a wheel rotates partially immersed in liquid metal, continuously bringing fresh material to the irradiation surface. This hydraulic approach maintains a precisely controlled target surface with minimum dimensions optimized for precision while ensuring continuous supply of plasma-forming material, thereby maintaining both manufacturing precision and radiation collection efficiency through material replenishment rather than relying solely on static small dimensions.
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 increases the useful power of EUV sources by improving plasma formation and radiation collection efficiency while mitigating contaminants, leading to enhanced performance in lithographic applications.
Implementation Method 1
a laser unit constructed and arranged to generate a beam of radiation directed onto the target surface so as to form a plasma
Implementation Method 2
form a plasma from said plasma-forming material
Implementation Method 3
a radiation collector comprising a plurality of grazing-incidence reflectors arranged to collect radiation emitted by the plasma and form a beam therefrom
Implementation Method 4
a filter constructed and arranged to attenuate at least one wavelength range of the beam
Data Source
AI summary
A source-collector device includes a target unit having a target surface of plasma-forming material and a laser unit to generate a beam of radiation directed onto the target surface to form a plasma from said plasma-forming material. A contaminant trap is provided to reduce propagation of particulate contaminants generated by the plasma. A radiation collector includes a one or more grazing-incidence reflectors arranged to collect radiation emitted by the plasma and form a beam therefrom, and a filter is configured to attenuate at least one wavelength range of the beam.