EUV Mirror Debris Management via Segmented Gas Flow
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Solution Overview
Problem
In extreme ultraviolet light generating devices, debris such as tin atoms tend to adhere to the reflection surface of the EUV light focusing mirror over time, leading to contamination and reduced efficiency due to the convection flow and thermal decomposition of stannane gas, which complicates the discharge of tin ions and atoms.
Innovation Solution
The implementation of a gas supplying device with a peripheral head that blows out a gas flow along the reflection surface of the EUV light focusing mirror, forming a composite gas flow that joins with the center gas flow to enhance the discharge of particles, thereby reducing debris adherence and improving the clean area of the mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gas flow is blown out along the reflection surface to discharge particles, then the discharge performance is improved, but the complexity of the gas supplying device increases due to the need for multiple peripheral heads
Solution Approach 1:
The gas supplying device is divided into multiple independent peripheral heads, each capable of blowing gas flow along different regions of the reflection surface. This segmentation allows the system to effectively discharge particles from various areas simultaneously, improving overall discharge performance while maintaining modular flexibility in the device structure.
2Productivity
If the gas flow rate is increased to enhance particle discharge, then the discharge performance is improved, but the thermal decomposition of stannane gas increases leading to more debris adherence
Solution Approach 1:
The gas flow is divided into multiple streams from different peripheral heads rather than using a single high-flow source. This segmentation distributes the thermal load and prevents localized overheating that causes stannane decomposition, while still achieving effective particle discharge through coordinated multi-point gas flow.
Solution Approach 2:
Each peripheral head provides gas flow with optimized local characteristics tailored to its specific position relative to the reflection surface and plasma generation region. This localized optimization ensures effective particle discharge from each area without excessive gas flow rates that would cause thermal decomposition and debris generation.
3Area of stationary object
If the peripheral heads are positioned along the outer peripheral portion to maximize coverage, then the clean area is improved, but the difficulty of discharging particles from the center region increases
Solution Approach 1:
The gas flow discharge strategy transitions from a single-dimensional approach (single source) to a multi-dimensional approach (multiple peripheral heads distributed along the periphery). This spatial distribution creates effective gas flow coverage across the entire reflection surface area, including central regions, by utilizing the geometric arrangement of multiple peripheral sources to achieve comprehensive particle discharge.
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 the re-deposition of tin atoms on the EUV light focusing mirror, maintaining a clean area and enhancing the discharge performance, even at higher gas flow rates, thus improving the long-term operational efficiency of the device.
Implementation Method 1
The plurality of peripheral heads may be configured to blow out a gas flow along the reflection surface
Implementation Method 2
a discharge device configured to discharge an ion or a particle, generated together with the plasma, from the discharge port along with the gas flow
Data Source
AI summary
An extreme ultraviolet light generating device may include a chamber, an EUV light focusing mirror provided therein, including a reflection surface having a concave curved shape and an outer peripheral portion around an outer edge of the reflection surface, and configured to focus EUV light radiated from plasma generated when a target is irradiated with laser light, a gas supplying device including peripheral heads provided on or along the outer peripheral portion; and a discharge device including a discharge path forming a discharge port near the outer peripheral portion, and configured to discharge an ion or a particle from the discharge port. The peripheral heads each may blow out a gas flow from the outer peripheral portion or a vicinity thereof along the reflection surface, and allow gas flows to join on the reflection surface to thereby form a gas flow along the reflection surface toward the discharge port.