EUV Light Source Plasma Position Adjustment via External Camera Feedback
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Solution Overview
Problem
EUV light source apparatuses experience positional variations due to thermal expansion, affecting the stability and accuracy of extreme ultraviolet light emission in high-temperature environments, particularly when using liquid tin as a plasma raw material and energy beam vaporization.
Innovation Solution
An extreme ultraviolet light source apparatus with a disc-shaped cathode and anode, a material supplier for liquid plasma raw material, an energy beam irradiation device, and an irradiation position adjusting mechanism, utilizing a photography device outside the high-temperature environment to estimate and adjust the plasma position based on visible light emission, ensuring consistent EUV light positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the EUV light source apparatus operates in a high-temperature environment to generate plasma, then the plasma generation efficiency is improved, but the position of the generated EUV light varies due to thermal expansion
Solution Approach 1:
The patent employs a feedback control mechanism where a camera captures the position of the plasma, and this information is fed back to an adjustment mechanism that modifies the plasma generation conditions. This closed-loop system continuously corrects position deviations caused by thermal expansion, maintaining stable EUV light output position while operating at high temperatures for efficient plasma generation.
Solution Approach 2:
The patent adjusts operational parameters such as the position of electrodes or the timing of energy beam irradiation in response to detected plasma position variations. By dynamically changing these parameters based on real-time feedback, the system compensates for thermal expansion effects and maintains consistent EUV light emission position despite high-temperature operation.
2Quantity of substance
If liquid tin is applied to rotating electrodes and vaporized by energy beam to generate plasma, then the plasma density is improved, but the electrodes thermally expand causing position variation
Solution Approach 1:
The camera-based detection system monitors plasma position in real-time, providing feedback that enables continuous adjustment of electrode positions or energy beam targeting. This feedback loop compensates for thermal expansion of the electrodes, maintaining stable plasma generation location and EUV light output position while preserving high plasma density through continued use of liquid tin vaporization.
Solution Approach 2:
The system performs preliminary detection of plasma position before significant position deviation occurs. By detecting position changes early and making preemptive adjustments to electrode or beam positioning, the system prevents large position variations while maintaining optimal plasma density conditions.
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
Maintains the position of extreme ultraviolet light at a desired location, minimizing thermal expansion effects and ensuring accurate emission, even in high-temperature conditions.
Implementation Method 1
an energy beam irradiation device configured to irradiate the plasma raw material on the cathode with an energy beam to vaporize the plasma raw material and generate a plasma raw material in a gas phase
Implementation Method 2
a power supply configured to supply electric power to the cathode and the anode to cause a discharge between the cathode and the anode for generating a plasma in the gap between the cathode and the anode, the plasma emitting extreme ultraviolet light
Implementation Method 3
a photography device disposed outside the housing and configured to photograph a visible-light image of a vicinity of the cathode and the anode, the vicinity including visible light emitted from the plasma
Implementation Method 4
Since thermal expansion displaces the entire EUV light source apparatus, the position of the EUV light generated by the EUV light source apparatus also varies. In addition, the electrodes thermally expand by the hot tin and by irradiation with the energy beam.
Data Source
AI summary
An extreme ultraviolet light source apparatus includes a disc-shaped cathode rotating about an axis, a disc-shaped anode rotating about an axis, an energy beam irradiation device irradiating a plasma raw material on the cathode with an energy beam to vaporize the plasma raw material, a power supply for causing a discharge between the cathode and the anode for generating a plasma in the gap between the cathode and the anode to emit extreme ultraviolet light, and an irradiation position adjusting mechanism for adjusting a position at which the cathode is irradiated with the energy beam. The cathode, the anode, and the irradiation position adjusting mechanism are accommodated in a housing. A photography device is disposed outside the housing and is configured to photograph a visible-light image of a vicinity of the cathode and the anode, the vicinity including visible light emitted from the plasma.