Rotating Plasma Plate Layout for Debris-Suppressed EUV Light Sources

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Solution Overview

Problem

Existing light source apparatuses for X-rays and EUV light face challenges in suppressing debris generation, which affects the stability and efficiency of radiation emission.

Innovation Solution

A light source apparatus with a rotatable plate member where the plasma raw material is supplied and irradiated with an energy beam, with the normal axis offset from the between-axes area, and a chamber configuration that includes gas supply to manage pressure and debris, reducing debris entry into the emission and incident chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a DPP or LDP light source apparatus uses discharge between electrodes to generate plasma, then EUV radiation can be produced, but debris is generated that interferes with the incident energy beam and emitted radiation

Engineering Contradiction:
ImproveEUV radiation generationVSAvoiddebris generation
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The harmful debris generation is separated from the useful EUV radiation generation by extracting the plasma raw material supply location away from the discharge region. The plate member is positioned so that the normal axis of the incident area is off from the between-axes area, causing debris to be generated away from the paths of the incident energy beam and emitted radiation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A gas flow is introduced as an intermediary medium to carry away debris from the plasma generation region. The gas flows from the region between the incident axis and emission axis toward the normal axis direction, preventing debris from interfering with the energy beam and radiation while maintaining the plasma generation process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the normal axis of the incident area is positioned in the between-axes area, then the configuration is simplified, but debris interferes with the energy beam and radiation extraction

Engineering Contradiction:
Improveconfiguration simplicityVSAvoiddebris interference
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The plate member is positioned asymmetrically such that the normal axis of the incident area is deliberately offset from the between-axes area. This asymmetric positioning ensures that debris generated during plasma formation does not lie in the path of the incident energy beam or the emitted radiation, resolving the interference problem while maintaining operational simplicity.

Inventive Principle:
Principle #4Asymmetry

3Object-generated harmful factors

If gas is supplied to blow debris away, then debris interference is reduced, but the system complexity increases

Engineering Contradiction:
Improvedebris interferenceVSAvoidsystem complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

A gas flow system is implemented to actively manage debris removal. Gas is supplied into the chamber and flows from the region between the incident axis and emission axis toward the normal axis direction, effectively carrying debris away from critical paths. This pneumatic approach provides controllable debris management without requiring complex mechanical removal systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 effectively suppresses debris, stabilizes radiation emission, and enhances the longevity of components by preventing debris from interfering with the energy beam and radiation extraction.

Implementation Method 1

The front surface of the plate member is supplied with plasma raw material and is irradiated with an energy beam to generate plasma and emit radiation

Methodology Applied
Scientific EffectEnergy beam irradiation: Laser Beam Welding

Implementation Method 2

A light source apparatus with a rotatable plate member where the plasma raw material is supplied and irradiated with an energy beam, with the normal axis offset from the between-axes area, and a chamber configuration that includes gas supply to manage pressure and debris

Methodology Applied
Scientific EffectGas pressure: Pressure Gradient

Data Source

PatentEP4255124B1Light source apparatus
Publication Date: 2024.10.16 USHIO INC
  • EP4255124B1 patent drawingFigure 1
  • EP4255124B1 patent drawingFigure 2
  • EP4255124B1 patent drawingFigure 3

AI summary

A light source apparatus (1) includes a beam introduction section, a plate member, a raw material supply section, and a radiation extraction section. The beam introduction section introduces an energy beam (EB). The plate member has a front surface (22a) and a back surface, is disposed at a location where the introduced energy beam (EB) is incident onto the front surface (22a), and is rotatable around a direction orthogonal to the front surface (22a) as its rotation axis direction. The raw material supply section supplies plasma raw material (23) to an incident area (25) in the front surface (22a) to generate plasma. The radiation extraction section extracts and emits radiation (R) from the generated plasma. The plate member is disposed such that the normal axis (NA) of the incident area (25) in the front surface (22a) is off from a between-axes area (54) configured between an incident axis (lA) of the energy beam incident onto the incident area (25) and an emission axis (EA) of the radiation.