EUV Light Source Plasma Density via Beam Focal Shift
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Solution Overview
Problem
Existing EUV light source devices face challenges in maintaining a high density of high temperature plasma raw material during discharge, leading to suboptimal EUV radiation generation due to the expansion of gasified raw material between electrodes, making it difficult to achieve the necessary ion density and electron temperature for efficient EUV radiation emission.
Innovation Solution
The surface of the raw material is positioned shifted from the focal point of the energy beam towards the irradiation entrance side, reducing free expansion and maintaining a high density of the plasma raw material during discharge, allowing for effective EUV radiation generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the raw material is gasified by energy beam irradiation between discharge electrodes, then the plasma is formed and EUV radiation can be generated, but the gasified raw material expands freely causing low density and insufficient ion density for efficient EUV radiation
Solution Approach 1:
The raw material surface is pre-positioned at a specific location (shifted from the focal point toward the irradiation entrance) before energy beam irradiation begins. This preliminary positioning ensures that when gasification occurs, the raw material is already in an optimal configuration that limits free expansion and maintains high density during the subsequent discharge process, enabling efficient EUV radiation generation.
Solution Approach 2:
The invention changes the spatial parameter of the raw material surface position relative to the energy beam focal point. By shifting the surface position toward the irradiation entrance side rather than placing it at the focal point, the geometry of gasification and subsequent plasma formation is altered, constraining expansion and maintaining higher density for improved EUV radiation efficiency.
2Quantity of substance
If the focal point of energy beam is positioned at the raw material surface, then complete gasification is achieved, but the plasma density becomes insufficient due to three-dimensional expansion
Solution Approach 1:
The invention modifies the spatial parameter by positioning the raw material surface away from the focal point toward the irradiation entrance. This parameter change transforms the expansion geometry from three-dimensional free expansion to a more constrained configuration, naturally maintaining higher plasma density without requiring complex active control mechanisms.
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 configuration ensures a high-density plasma is maintained at the discharge region, enhancing the ion density and electron temperature, thereby improving the efficiency and stability of EUV radiation emission with a wavelength of 13.5 nm.
Implementation Method 1
an energy beam radiating means radiating a focused energy beam towards the raw material having been supplied onto the discharge electrodes to gasify the raw material and to start a discharge between the pair of electrodes
Implementation Method 2
a discharge is generated between the electrodes in this atmosphere and an initial plasma is formed
Implementation Method 3
By means of the effect of the self-magnetic field of the direct current flowing between the electrodes because of the discharge, the above mentioned initial plasma is condensed. Thereby, the density of the initial plasma becomes high and the plasma temperature increases abruptly. In the following, this effect is referred to as pinch effect.
Implementation Method 4
a method which generates a high temperature plasma by heating and exciting an EUV radiation species and extracts the EUV radiation emitted from this plasma
Data Source
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AI summary
The invention relates to an extreme ultraviolet light source device, comprising a pair of discharge electrodes (11, 12) arranged oppositely to each other, a pulsed power supply means (8) supplying pulsed power to said discharge electrodes (11, 12), a raw material supply means (11b, 12b) supplying a liquid or solid raw material for the emission of extreme ultraviolet radiation to said discharge electrodes (11, 12) and onto these electrodes (11, 12), and an energy beam radiating means (23a) radiating a focused energy beam (23) towards said raw material (11a) having been supplied onto said discharge electrodes (11, 12) to gasify said raw material (11a) and to start a discharge between said pair of electrodes (11, 12).The surface of said raw material (11a) is arranged at a position shifted from the focal point (P) of the energy beam (23) towards the irradiation entrance side of the energy beam (23).