EUV Pellicle Nanotube Membrane Composite Coating
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Solution Overview
Problem
In extreme ultraviolet (EUV) lithography, pellicles face challenges with maintaining high transparency, mechanical strength, and resistance to contamination and heat, especially due to environmental adsorption and radiation exposure, which existing materials like resin-based films cannot adequately address.
Innovation Solution
A pellicle for EUV photo masks is designed using a network membrane composed of multiwall or single wall nanotubes, such as carbon nanotubes or non-carbon based materials like boron nitride, forming a mesh structure with additional cover layers to enhance mechanical strength and EUV transmittance, and treated to improve adhesion and surface properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin-based films are used for EUV pellicles, then ease of manufacture is improved, but EUV transparency and resistance to environmental adsorption and radiation deteriorate
Solution Approach 1:
The patent employs a composite membrane structure combining organic resin layer and inorganic hard coating layer. The resin layer provides ease of manufacture and flexibility, while the inorganic hard coating layer enhances EUV transparency, resistance to environmental adsorption, and radiation hardness. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the membrane materials to optimize performance. The inorganic hard coating layer changes the surface energy and chemical composition parameters to resist environmental adsorption while maintaining EUV transparency. This parameter optimization allows the pellicle to achieve both ease of manufacture and high reliability.
2Illumination intensity
If thinner membranes are used to improve EUV transparency, then EUV transmittance is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent uses a composite structure where a thin organic resin layer (providing high EUV transmittance) is combined with an inorganic hard coating layer (providing mechanical strength). The inorganic layer acts as a reinforcement that allows the overall membrane to be thinner while maintaining sufficient mechanical strength for handling and use.
3Ease of manufacture
If existing pellicle materials are used, then ease of manufacture is maintained, but resistance to contamination and heat deteriorates
Solution Approach 1:
The inorganic hard coating layer provides superior resistance to contamination and heat compared to conventional organic materials. The coating's chemical inertness and thermal stability prevent adsorption of environmental contaminants and resist degradation under EUV radiation and heat, while the manufacturing process remains compatible with existing techniques.
4Device complexity
If conventional pellicles are used, then device complexity is minimized, but performance reliability under EUV conditions deteriorates
Solution Approach 1:
The patent introduces a composite membrane structure with organic and inorganic layers to achieve high performance reliability under EUV conditions. Despite the added material complexity, the manufacturing process is designed to be integrated into existing workflows, minimizing the increase in device complexity while maximizing performance improvement.
Data Source
AI summary
In a method of manufacturing a pellicle for an extreme ultraviolet (EUV) photomask, a membrane of Sp2 carbon is formed, a treatment is performed on the membrane to change a surface property of the membrane, and after the treatment, a cover layer is formed over the membrane.