EUV Light Collecting Mirror Segmentation for Debris Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing EUV light generating apparatuses face issues with debris accumulation on the reflective surfaces of the EUV light collecting mirrors, leading to reduced reflectance and increased maintenance costs due to frequent replacements.
Innovation Solution
The apparatus incorporates a light collecting mirror with a first mirror portion and a second mirror portion, where the second mirror portion is positioned at a location with lower magnetic flux density, preventing debris accumulation by directing it away from the central axis of the magnetic field, thus reducing adhered debris formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single mirror surface is used in the EUV light collecting mirror, then the device complexity is reduced, but debris accumulates on the reflective surface leading to reduced reflectance
Solution Approach 1:
The light collecting mirror is divided into a first mirror portion and a second mirror portion with different reflective surfaces positioned at different magnetic flux density levels. This segmentation allows debris to be directed away from the central axis while maintaining overall mirror functionality, resolving the contradiction between reliability and complexity.
Solution Approach 2:
Different portions of the mirror are positioned in different magnetic field environments. The first reflective surface is at a position with higher magnetic flux density while the second reflective surface is at a position with lower magnetic flux density. This local differentiation optimizes debris control at specific locations without requiring complete redesign of the entire mirror system.
2Productivity
If the mirror is positioned closer to the plasma generation region to improve light collection efficiency, then productivity increases, but debris accumulation worsens due to higher magnetic flux density
Solution Approach 1:
The solution moves from a single-position mirror to a multi-position mirror system where reflective surfaces are distributed at different locations along the magnetic field gradient. This dimensional distribution allows the system to simultaneously achieve good light collection (by having surfaces at various positions) and debris control (by positioning surfaces at lower magnetic flux density regions).
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 formation of adhered debris on the EUV light collecting mirror, maintaining the reflectance and reducing the frequency of mirror replacements, thereby lowering the operational costs of the EUV light generating apparatus.
Implementation Method 1
a light collecting mirror that reflects and focuses extreme ultraviolet light
Implementation Method 2
a magnet that generates a magnetic field
Data Source
AI summary
An extreme ultraviolet light generating apparatus includes a light collecting mirror that reflects and focuses extreme ultraviolet light, and a magnet that generates a magnetic field. The light collecting mirror includes a first mirror portion that includes a first reflective surface formed by a portion of a spheroidal surface, and a second mirror portion that includes a second reflective surface having a focal point at substantially the same position as a focal point of the first reflective surface, formed by a portion of a spheroidal surface different from that of the first reflective surface. The second reflective surface is provided at a position at which a magnetic flux density caused by the magnetic field is lower than that of the first reflective surface.