EUV Collector Mirror Cleaning via Carrier-Mounted Spray System
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Solution Overview
Problem
Collector mirrors in extreme ultraviolet light sources become dirty due to debris from the plasma, leading to reduced reflectivity and efficiency, as they are exposed to tin or tin compounds during operation, necessitating an effective cleaning method to restore reflectivity within a certain baseline.
Innovation Solution
A method involving the removal of the collector mirror from its chamber, mounting it on a carrier, and using a cleaning agent like hydrochloric acid to clean the reflective surface, followed by rinsing and drying, ensuring the reflectivity is within 10% of the baseline, with the carrier designed to facilitate efficient cleaning and handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the collector mirror is continuously operated in the EUV light source, then the light source productivity is improved, but the collector mirror becomes dirty and reflectivity decreases
Solution Approach 1:
The cleaning system is prepared in advance with multiple nozzles positioned to spray cleaning agents onto the collector mirror surface before significant contamination occurs, allowing for preventive maintenance without interrupting the primary EUV light source operation
Solution Approach 2:
A carrier structure is introduced as an intermediary component to hold and position the collector mirror, enabling easy removal and reinstallation of the mirror for cleaning purposes while maintaining the overall system productivity
2Reliability
If the collector mirror is removed for cleaning, then the reflectivity is restored, but the maintenance time and operational downtime increase
Solution Approach 1:
The collector mirror is mounted on a carrier in advance, which prepares the mirror for quick removal and reinstallation during cleaning cycles, minimizing the time the light source needs to be taken offline for maintenance
Solution Approach 2:
The cleaning system uses movable nozzles that can dynamically adjust their positions and angles to optimize cleaning coverage of the collector mirror surface, reducing the time required to achieve effective cleaning results
3Reliability
If a cleaning agent is sprayed onto the collector mirror, then the debris is removed and reflectivity is restored, but the cleaning agent may damage the multilayer coating
Solution Approach 1:
The cleaning system carefully controls parameters such as spray pressure, nozzle distance, and cleaning agent flow rate to optimize the balance between effective debris removal and protection of the delicate multilayer coating on the collector mirror
Solution Approach 2:
The system uses multiple nozzles to create overlapping spray patterns that evenly distribute the cleaning agent across the collector mirror surface, ensuring uniform cleaning without concentrated areas that could damage the coating
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
The method effectively cleans the collector mirror, restoring its reflectivity to within 10% of the baseline, ensuring the EUV light source operates efficiently by removing debris and maintaining reflectivity, thus enhancing the light source's performance.
Implementation Method 1
applying a cleaning agent to a reflective surface of the collector mirror by spraying the cleaning agent through a plurality of nozzles directed toward the collector mirror reflective surface
Data Source
AI summary
A collector mirror of an extreme ultraviolet light source is cleaned by removing the collector mirror from a chamber of the extreme ultraviolet light source; mounting the collector mirror to a carrier; inserting the carrier with the collector mirror into a cleaning tank; applying a cleaning agent to a reflective surface of the collector mirror by spraying the cleaning agent through a plurality of nozzles directed toward the collector mirror reflective surface until the collector mirror reflective surface is clean; rinsing the applied cleaning agent from the collector mirror reflective surface; and drying the collector mirror reflective surface.