EUV Collector Mirror Radical Supplier for Tin Debris Removal
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Solution Overview
Problem
Current EUV light generation systems face challenges in maintaining mirror reflectance due to debris deposition, particularly from tin, which affects the quality of extreme ultraviolet light used in semiconductor microfabrication processes, especially at feature sizes below 32 nm.
Innovation Solution
Incorporating a radical supplier, such as a hydrogen gas supply unit, within the chamber apparatus to generate hydrogen radicals that react with tin debris on the EUV collector mirror, converting it into a gas and preventing reflectance reduction, while positioning the radical supplier close to the mirror surface to effectively address debris accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a collector mirror is used to collect EUV light, then light collection efficiency is improved, but debris deposition on the mirror surface causes reflectance reduction
Solution Approach 1:
The patent introduces an etching gas supply unit that supplies etching gas to the mirror surface before debris accumulation becomes problematic. This preliminary action prevents debris deposition by maintaining a clean mirror surface through continuous or periodic etching gas flow, thereby preserving reflectance while maintaining light collection efficiency
Solution Approach 2:
The etching gas acts as an intermediary substance between the plasma source and the collector mirror. It chemically reacts with tin debris in the plasma, converting it into volatile compounds that are removed from the mirror surface, thus protecting the mirror from direct debris deposition while allowing the mirror to continue collecting EUV light effectively
2Stability of the object's composition
If the chamber is sealed to maintain vacuum, then plasma generation stability is improved, but debris generated inside cannot be removed
Solution Approach 1:
The patent extracts harmful debris from the chamber environment by introducing etching gas that selectively reacts with and removes tin debris through chemical etching. The etching gas transports debris molecules out of the plasma region and onto the mirror surface where they are converted into removable compounds, effectively extracting contaminants while maintaining the sealed vacuum chamber
Solution Approach 2:
The patent changes the chemical parameters of the chamber environment by introducing etching gas (such as fluorocarbon gases). This parameter change enables chemical reactions that transform non-volatile tin debris into volatile compounds, fundamentally altering the debris removal mechanism from physical extraction to chemical transformation, allowing continuous operation without compromising plasma stability
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 effectively reduces the deposition of tin debris on the EUV collector mirror, thereby maintaining the reflectance and ensuring the quality of EUV light for microfabrication processes, even at smaller feature sizes.
Implementation Method 1
a radical supplier, such as a hydrogen gas supply unit, within the chamber apparatus to generate hydrogen radicals that react with tin debris on the EUV collector mirror, converting it into a gas
Implementation Method 2
a Laser Produced Plasma (LPP) type system in which plasma is generated by irradiating a target material with a laser beam
Implementation Method 3
a Discharge Produced Plasma (DPP) type system in which plasma is generated by electric discharge
Data Source
AI summary
A chamber apparatus, which may be used with an external apparatus having an obscuration region, may include: a chamber in which EUV light is generated; a collector mirror having a first through-hole formed in a region aside from the center thereof and configured to collect the EUV light generated inside the chamber, the collector mirror being positioned such that the first through-hole is located in a region substantially corresponding to the obscuration region; and an etching gas supply unit provided in the first through-hole and configured to supply an etching gas into the chamber.