EUV Light Source Purge Gas Shielding for Window Protection
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Solution Overview
Problem
The efficiency of EUV light generation is reduced due to window and optics deterioration caused by plasma-induced atom and ion scattering in EUV light generation chambers, leading to energy absorption and reflectance loss, which can result in decreased light collection and potential damage to components.
Innovation Solution
Incorporating a purge gas supply unit to protect the window and optical surfaces within the EUV light generation chamber by shielding them from scattered atoms and ions, using inactive gases like Ar to prevent deterioration and maintain surface integrity, and optimizing the laser beam collection optics to increase the distance between the plasma and optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the window and optical components are placed close to the plasma source to maximize light collection, then the EUV light collection efficiency is improved, but the components deteriorate rapidly due to exposure to scattered atoms and ions from the plasma
Solution Approach 1:
A gas flow shield (purge gas supply unit) is introduced as an intermediary between the plasma source and the window/optical components. This shield creates a protective gas barrier that prevents scattered plasma atoms and ions from directly contacting and deteriorating the optical components, while still allowing EUV light to pass through for collection
2Use of energy by moving object
If the window material is made highly transparent to laser beams, then the laser beam transmission efficiency is improved, but the window absorbs excessive plasma radiation energy and deteriorates
Solution Approach 1:
An inert gas atmosphere is created between the plasma source and the window by supplying purge gas. This inert environment protects the window from plasma-induced deterioration while maintaining its high transparency to laser beams, as the inert gas does not interfere with laser transmission but effectively shields against plasma radiation
3Use of energy by moving object
If the vacuum degree in the EUV light generation chamber is increased to prevent EUV light absorption, then the light transmission is improved, but the scattered plasma atoms and ions more easily reach and damage the window and optics
Solution Approach 1:
A gas flow shield acts as an intermediary layer between the high-vacuum plasma environment and the window/optical components. This shield allows the vacuum to be maintained for EUV light transmission while simultaneously blocking scattered plasma particles from reaching and contaminating the optical surfaces
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
Prevents window and optics deterioration, maintains EUV light generation efficiency, and reduces the risk of component damage by effectively shielding surfaces from plasma-induced radiation and heat, thereby ensuring stable and high-efficiency EUV light production.
Implementation Method 1
generates extreme ultra violet light by irradiating a target material with a laser beam and thereby turning the target material into plasma
Implementation Method 2
turning the target material into plasma
Implementation Method 3
a window which is provided in the extreme ultra violet light generation chamber and allows the laser beam to be transmitted into the extreme ultra violet light generation chamber
Implementation Method 4
a laser beam collecting optics which collects the laser beam generated by the driver laser to a target material supplied into the extreme ultra violet light generation chamber so as to generate plasma
Implementation Method 5
an extreme ultra violet light collecting optics which collects the extreme ultra violet light generated from the plasma to output the extreme ultra violet light
Implementation Method 6
a purge gas supply unit which supplies a purge gas for protecting a surface of the window at an inner side of the extreme ultra violet light generation chamber and/or an optical surface of at least one optical device
Data Source
AI summary
An EUV light source apparatus capable of preventing the efficiency of generation of EUV light from decreasing due to deterioration of a window of an EUV light generation chamber. The EUV light source apparatus includes an EUV light generation chamber provided with a window, a driver laser which generates a laser beam, a concave lens which enlarges the laser beam, a convex lens which collimates the enlarged laser beam, a parabolic concave mirror which is arranged in the EUV light generation chamber and reflects the collimated laser beam to collect the laser beam to a target material, a parabolic concave mirror adjusting mechanism which adjusts position and angle of the parabolic concave mirror, an EUV light collector mirror which collects EUV light, and a purge gas supply unit which supplies a purge gas for protecting the window and the parabolic concave mirror.