EUV Chamber Surface Cleaning Using Induced Plasma Radicals
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Solution Overview
Problem
Extreme ultraviolet (EUV) light sources face challenges in cleaning debris from surfaces within their chambers, as existing methods often require heating, which can lead to spitting of debris and are complex and costly, while also not being able to operate effectively in the presence of molecular hydrogen without oxygen.
Innovation Solution
A method and apparatus that generate a plasma state of a material adjacent to a non-electrically conductive body within the chamber, using electromagnetic induction to create plasma particles that chemically react with debris, removing it without heating the structure and operating in the presence of hydrogen, without oxygen, by flowing an electric current through an electrical conductor adjacent to the non-electrically conductive body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heating methods are used to remove debris from surfaces, then debris removal effectiveness is improved, but the risk of spitting debris increases and system complexity increases
Solution Approach 1:
The invention changes the fundamental parameter of debris removal from thermal (heating) to chemical (plasma). By introducing plasma particles that chemically react with debris to form volatile compounds, the method achieves effective debris removal without the harmful thermal effects that cause spitting. This parameter change resolves the contradiction by decoupling debris removal effectiveness from the harmful spitting effect.
2Manufacturing precision
If heating methods are used to remove debris, then debris removal is achieved, but system complexity and cost increase
Solution Approach 1:
The invention substitutes the mechanical/thermal debris removal system with a chemical plasma-based system. Instead of using complex heating apparatus, temperature control systems, and mechanical scraping mechanisms, the method uses plasma generation through electromagnetic induction to chemically convert and remove debris. This substitution dramatically reduces system complexity while maintaining or improving debris removal capability.
3Manufacturing precision
If plasma cleaning is performed in the presence of molecular hydrogen, then cleaning effectiveness is improved, but oxygen presence becomes problematic
Solution Approach 1:
The invention applies local quality by creating a localized plasma environment with specific chemical properties adjacent to the surface being cleaned. The plasma is generated in a confined region where hydrogen can be present without requiring the entire chamber to be oxygen-free. This localized approach allows the cleaning process to be adapted to hydrogen-rich environments while maintaining cleaning effectiveness, resolving the contradiction between cleaning performance and environmental flexibility.
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 removes debris from EUV light source surfaces without heating, maintaining a low chamber temperature, and operating in hydrogen environments, thus preventing spitting and reducing complexity and costs, while maintaining the EUV light source's efficiency.
Implementation Method 1
The generation of the plasma state of the material includes electromagnetically inducing an electric current at the location adjacent the non-electrically conductive body to thereby transform the material that is adjacent the non-electrically conductive body from a first state into the plasma state
Implementation Method 2
The plasma state of the material includes plasma particles, at least some of which are free radicals of the material. The method also includes enabling the plasma particles to pass over the structure surface to remove debris from the structure surface
Data Source
AI summary
In some general aspects, a surface of a structure within a chamber of an extreme ultraviolet (EUV) light source is cleaned using a method. The method includes generating a plasma state of a material that is present at a location adjacent to a non-electrically conductive body that is within the chamber. The generation of the plasma state of the material includes electromagnetically inducing an electric current at the location adjacent the non-electrically conductive body to thereby transform the material that is adjacent the non-electrically conductive body from a first state into the plasma state. The plasma state of the material includes plasma particles, at least some of which are free radicals of the material. The method also includes enabling the plasma particles to pass over the structure surface to remove debris from the structure surface without removing the structure from the chamber of the EUV light source.