EUV Radiation Source Electrode Debris Management
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Solution Overview
Problem
Debris particles produced during the operation of radiation sources for EUV or soft X-ray generation can deposit on surfaces, causing shadowing and damage, leading to reduced service life and potential damage to workpieces.
Innovation Solution
The method involves arranging the region with respect to the first opening such that the movement paths of debris particles are predominantly outside the area delimited by the opening, using a current origin and energy beam to direct debris particles away from the opening, and maintaining the electrodes and insulators outside these paths to prevent deposition and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a plasma discharge is used to generate EUV or soft X-ray radiation, then radiation in the wavelength range from 1 nm to 30 nm is produced, but debris particles are produced in at least one region of at least one of the electrodes which can deposit on surfaces and cause shadowing and damage
Solution Approach 1:
The harmful debris particles are extracted from the plasma discharge region and directed away from the first opening through which radiation escapes. The electrode geometry and electric field distribution are designed to separate the paths of useful radiation and harmful debris particles, allowing radiation to exit through the opening while debris particles are confined to the discharge space or directed toward the second electrode for capture.
Solution Approach 2:
The second electrode acts as an intermediary element that captures and retains debris particles produced during plasma discharge. By positioning the second electrode strategically and maintaining appropriate voltage differential, debris particles are directed toward it and retained, preventing them from reaching surfaces outside the discharge chamber while allowing radiation to pass through the first opening.
2Productivity
If debris particles are produced during electrode operation, then radiation can be generated, but the service life of collectors is shortened due to deposition and sputtering
Solution Approach 1:
Debris particles are extracted from the path of radiation and directed toward the second electrode. The electric field configuration and electrode geometry ensure that harmful particles are separated from the first opening and collector areas, preventing deposition that would otherwise shorten service life while maintaining continuous radiation generation capability.
Solution Approach 2:
The second electrode serves as an intermediary trap for debris particles. By positioning it to intercept particle trajectories and maintaining appropriate electrical conditions, the second electrode captures and retains particles before they can reach and damage collectors, thereby extending collector service life while preserving radiation productivity.
3Illumination intensity
If the first opening is made larger to forward more radiation, then radiation intensity increases, but more debris particles can reach the opening and cause damage
Solution Approach 1:
The harmful effect of larger opening is counteracted by extracting debris particles from the radiation path. The electric field distribution and electrode geometry are optimized to ensure that even with a larger first opening for high radiation intensity, debris particles are directed away from the opening and toward the second electrode for capture, preventing deposition damage.
Solution Approach 2:
The second electrode acts as an intermediary barrier that captures debris particles before they can reach the first opening. This allows the first opening to be made larger for high radiation intensity without proportionally increasing debris particle deposition, as the second electrode intercepts and retains particles in the discharge space.
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
This approach effectively retains most debris particles within the electrode system, preventing them from reaching the first opening and reducing the risk of shadowing and damage, thereby extending the service life and ensuring reliable plasma ignition even at high repetition rates.
Implementation Method 1
a plasma is ignited in the working gas, the generated radiation of which plasma is forwarded via a first opening for further use
Implementation Method 2
The ignited plasma is supplied with electrical energy via the electrodes, wherein the plasma is heated to temperatures of several tens of eV, so that the plasma emits radiation in the wavelength range from 1 to 30 nm
Implementation Method 3
a laser beam or energy beam vaporizes a supplied medium in a predefined region where a first and second electrode are at a small distance from one another. The vapor is ignited to form a plasma
Implementation Method 4
The corpuscular radiation is produced for example by electrode erosion which naturally occurs as current flows through
Implementation Method 5
The vapor is ignited to form a plasma which is the source of an extreme ultraviolet radiation or soft X-ray radiation that is to be generated
Implementation Method 6
The vapor is ignited to form a plasma which is the source of an extreme ultraviolet radiation or soft X-ray radiation that is to be generated
Data Source
AI summary
A method and an apparatus generate radiation in the wavelength range from about 1 nm to about 30 nm by an electrically operated discharge, which can be used in lithography or in metrology. A working gas is provided between two electrodes. Plasma is ignited in the working gas to generate radiation which is forwarded via an opening for further use. Debris particles are produced in at least one region of at least one of the electrodes. To retain the debris particles, the region is arranged with respect to the opening in such a way that movement paths of the debris particles run at least predominantly outside an area delimited by the opening.