EUV Radiation Source Evaporation Surface for Debris Mitigation
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Solution Overview
Problem
Contamination particles generated by EUV radiation sources in lithographic apparatuses, particularly plasma sources, cause damage to mirrors and other components due to their presence in the vicinity of the plasma source.
Innovation Solution
A radiation source with a gas injector to direct a gas flow into the chamber, an evaporation surface maintained at a temperature below the vapor pressure of the debris, and a conically-shaped body with low-emissivity inner and high-emissivity outer walls, along with a rough evaporation surface to efficiently divert and evaporate debris particles, reducing their impact and presence near the collector mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a plasma source is used to generate EUV radiation, then the radiation wavelength is shortened to about 13 nm, but contamination particles are created as by-products that damage mirrors and components
Solution Approach 1:
The harmful contamination particles are extracted from the plasma source environment by directing a gas flow toward the plasma source, which carries the particles away from critical components like mirrors. This separation removes the harmful factor while preserving the useful EUV radiation generation.
Solution Approach 2:
A gas flow is introduced as an intermediary medium between the plasma source and the optical components. This gas flow acts as a carrier that transports contamination particles away from the plasma source region, preventing direct contact with mirrors and other sensitive parts while allowing the plasma to continue generating EUV radiation.
2Object-generated harmful factors
If a gas flow is directed toward the plasma source to remove contamination particles, then particle damage is reduced, but the device complexity increases due to the gas injector and flow control systems
Solution Approach 1:
The gas flow system serves multiple functions: it removes contamination particles from the plasma source environment, provides a medium for particle transport, and can be adjusted to control the plasma source's operational characteristics. This multi-functionality justifies the added device complexity by delivering several benefits through a single system.
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
Effectively mitigates the damage caused by contamination particles by evaporating and diverting them away from critical components, maintaining the cleanliness and functionality of the lithographic apparatus.
Implementation Method 1
an evaporation surface maintained at a temperature below the vapor pressure of the debris
Implementation Method 2
a gas injector arranged to direct a gas flow into the chamber
Implementation Method 3
a conically-shaped body with low-emissivity inner and high-emissivity outer walls
Data Source
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AI summary
A radiation source (50) is configured to produce extreme ultraviolet radiation. The radiation source includes a chamber in which, in use, a plasma (P) is generated, and an evaporation surface (62) configured to evaporate a material formed as a by-product (MP) from the plasma and that is emitted to the evaporation surface. A method for removing a by-product material in or from a plasma radiation source of a lithographic apparatus includes evaporating a material which, in use, is emitted to that surface from the plasma.