EUV Radiation Source Electrode Lifetime Extension
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Solution Overview
Problem
Existing extreme ultraviolet radiation sources using metal emitters face issues with electrode lifetime due to excessive emitter material deposition and thermal erosion, leading to reduced efficiency and operational failures.
Innovation Solution
A method and arrangement where individual volumes of starting material are injected into the discharge area at a distance from the electrodes, pre-ionized by an energy beam, and plasma is generated using a Z-pinch type gas discharge, maximizing the distance between plasma generation and electrodes to prevent metal deposition and extend electrode lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal emitters are supplied in the form of gaseous compounds or continuous flow, then the emission process is sustained, but excessive emitter material is introduced into the discharge chamber leading to metal deposits and operational failure
Solution Approach 1:
The emitter material supply is segmented into discrete individual volumes (droplets or globules) rather than continuous flow or gaseous compounds. This segmentation allows precise control of the amount of emitter material introduced into the discharge chamber, preventing excessive deposition while maintaining sustained emission through sequential injection of individual volumes.
Solution Approach 2:
The individual volumes of emitter material are pre-ionized by the energy beam before being introduced into the discharge area. This preliminary ionization action ensures that the emitter material is ready for immediate plasma generation upon introduction, maintaining efficient emission while controlling the quantity of material added to the chamber.
2Power
If electrodes are used with high current density discharge, then radiation output is increased, but thermal erosion and metal deposition reduce electrode lifetime
Solution Approach 1:
The harmful effect of thermal erosion and metal deposition is extracted and separated from the electrode surface by maximizing the distance between the plasma generation location and the electrodes. The plasma is generated in a location remote from the electrodes, allowing high power discharge to occur without direct thermal contact with the emitter material or deposition on the electrode surfaces, thus extending electrode lifetime.
Solution Approach 2:
An intermediary region is created between the electrodes and the plasma generation location. This intermediary space allows the high-current discharge to generate radiation without the plasma directly contacting the electrodes, reducing thermal erosion and metal deposition effects on the electrode surfaces while maintaining high radiation output.
3Productivity
If emitter material is supplied continuously, then radiation generation is maintained, but conversion efficiency decreases due to excess material and thermal stress
Solution Approach 1:
Continuous supply of emitter material is segmented into discrete individual volumes injected at controlled intervals. This segmentation enables precise control of the emitter material quantity, ensuring that only the necessary amount is introduced for each plasma generation cycle, thereby maintaining radiation generation continuity while optimizing conversion efficiency by eliminating energy waste from excess material.
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 significantly extends electrode lifetime, reduces metal deposition, and optimizes emitter material usage, allowing for efficient generation of extreme ultraviolet radiation with improved conversion efficiency and reduced thermal stress on electrodes.
Implementation Method 1
an energy beam source (12) for pre-ionization of a starting material (9) serving to generate radiation
Implementation Method 2
a pulsed high-current discharge of greater than 10 kA ignites in a gas of determined density and, as a result of the magnetic forces and the dissipated power, a very hot (kT>20 eV) and dense plasma is generated
Implementation Method 3
However, due to the rotation of the electrode, the equilibrium temperature can be kept low enough that even the temperature peaks on the electrode surface remain below the melting temperature of tungsten
Implementation Method 4
the vapor is ignited by a gas discharge to form a plasma
Data Source
AI summary
The object of an arrangement and a method for the generation of extreme ultraviolet radiation is to construct the radiation source with an increased lifetime of the electrodes for using various emitters, wherein deposits inside the discharge chamber are reduced considerably when using metal emitters. The starting material is supplied as a continuous series of individual volumes which are introduced successively by directed injection and are pre-ionized by a pulsed energy beam. At least the electrode that is thermally loaded to a comparatively greater degree is constructed as a rotating electrode.