EUV Collector Inspection Using UV-VIS Reflection Spectra
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Solution Overview
Problem
EUV collectors in EUV facilities are prone to contamination from by-products of tin droplet vaporization or plasma, leading to reduced EUV reflectance and equipment productivity.
Innovation Solution
An EUV collector inspection apparatus with a light blocking cover, a UV-VIS band light source, and a spectrometer to analyze the spectrum of reflected light for precise contamination assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the EUV collector is used continuously in the EUV facility, then productivity is maintained, but contamination accumulates on the reflective surface degrading EUV reflectance
Solution Approach 1:
The inspection apparatus performs contamination assessment before the EUV reflectance degrades to a level that affects productivity. By detecting contamination early using UV-VIS light reflection analysis, maintenance can be scheduled proactively to clean or replace the EUV collector, preventing productivity loss while maintaining reliable reflectance performance.
2Reliability
If the EUV collector is cleaned or replaced frequently, then EUV reflectance is maintained, but productivity is reduced due to maintenance interruptions
Solution Approach 1:
The inspection apparatus provides continuous feedback on the contamination state of the EUV collector by analyzing the reflection spectrum. This feedback enables condition-based maintenance, where cleaning or replacement is performed only when contamination reaches a threshold that would affect reflectance, thereby maintaining reliable performance while minimizing maintenance interruptions to productivity.
3Device complexity
If conventional inspection methods are used, then the inspection process is simple, but measurement precision is insufficient to accurately assess contamination state
Solution Approach 1:
The inspection apparatus changes the parameter of light wavelength by using UV-VIS band light instead of visible light alone. This parameter change enables detection of contamination that is not visible to the human eye, significantly improving measurement precision for assessing the contamination state of the EUV collector reflective surface.
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
Precisely determines the contamination state and reflectance of EUV collectors, enabling effective maintenance and preventing productivity loss in EUV facilities.
Implementation Method 1
detecting a spectrum of reflected light from the irradiated light reflected from the front surface of the EUV collector
Implementation Method 2
a spectrometer above the light source and configured to detect a spectrum of reflected light
Data Source
AI summary
An extreme ultraviolet (EUV) collector inspection apparatus includes a light blocking cover covering a front surface of an EUV collector to be inspected and providing a space portion in which external light is blocked, a light source in the space portion, the light source having a pillar shape extending along a central axis of the EUV collector, the light source configured to output irradiated light ranging from an ultraviolet (UV) band to a visible light (VIS) band, and a spectrometer above the light source and configured to detect a spectrum of reflected light from the irradiated light reflected from the front surface of the EUV collector. The apparatus or a controller associated therewith may be configured to inspect a contamination state of the front surface of the EUV collector based on the spectrum of reflected light.