Silicon Carbide Nanostructure Pellicles for Flat EUV Transmission
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Solution Overview
Problem
Existing pellicles for extreme ultraviolet (EUV) lithography systems suffer from issues such as wrinkling, difficulty in maintaining a flat form, and vulnerability to hydrogen radicals, leading to degradation and failure, while current coatings introduce weight and reduce EUV transmission.
Innovation Solution
A pellicle membrane composed of silicon carbide nanostructures, such as silicon carbide nanotubes, which are interconnected and self-supporting, providing high mechanical strength, resistance to high temperatures, and resistance to hydrogen radicals, maintaining a flat form and high EUV transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If carbon nanotubes are used for pellicle membranes, then high temperature stability and EUV radiation transmittance are improved, but resistance to hydrogen radicals deteriorates
Solution Approach 1:
The invention uses composite materials by combining silicon carbide nanostructures with carbon nanotubes. The silicon carbide provides hydrogen radical resistance while the carbon nanotube framework maintains the membrane's structural integrity, thermal stability, and EUV transmittance. This composite approach resolves the contradiction by integrating materials with complementary properties.
2Reliability
If a thin coating is deposited on carbon nanotubes to improve hydrogen resistance, then resistance to hydrogen radicals is improved, but EUV transmission and mechanical properties deteriorate
Solution Approach 1:
The invention employs a porous silicon carbide nanostructure framework that provides hydrogen radical resistance without requiring dense coatings. The nanostructured porous material allows EUV radiation to pass through while the silicon carbide composition provides chemical resistance to hydrogen radicals, eliminating the need for additional coating layers that would block EUV transmission.
3Ease of manufacture
If continuous thin films are used for pellicles, then ease of manufacture is improved, but mechanical stability and flatness deteriorate due to wrinkling
Solution Approach 1:
The invention segments the continuous thin film into discrete silicon carbide nanostructures arranged in a framework. This segmentation prevents the wrinkling issues of continuous films while maintaining manufacturability through scalable nanostructure assembly. The discrete nanostructured elements provide mechanical stability without the defects inherent in continuous thin films.
4Illumination intensity
If the pellicle membrane is made thinner to improve EUV transmission, then EUV transmission is improved, but mechanical strength deteriorates
Solution Approach 1:
The invention applies local quality by concentrating material properties at the nanoscale level. The silicon carbide nanostructures provide localized strength and chemical resistance where needed, while the overall membrane remains thin for EUV transmission. The nanostructured framework distributes mechanical loads efficiently, maintaining strength despite reduced overall thickness.
Data Source
AI summary
Disclosed are pellicles for use in extreme ultraviolet (EUV) lithography, the pellicles comprising silicon carbide nanostructures, and exhibiting high transmittance of EUV exposure light and high mechanical strength, as well as methods of using these pellicles.