CNT Multilayer Protective Coating for Hydrogen Plasma-Resistant Pellicles
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Solution Overview
Problem
The challenge in EUV lithography is finding suitable pellicle membrane materials with high transmission and stability at EUV wavelengths, and pristine carbon nanotubes (CNTs) are vulnerable to damage from hydrogen plasma due to crystalline defects, shortening their lifespan.
Innovation Solution
A multilayer protective coating is applied to CNTs, comprising a stress control layer, hydrogen permeation barrier layer, and optionally a hydrogen reduction layer, to enhance resistance to hydrogen plasma etching and maintain EUV transmittance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pristine carbon nanotubes are used as pellicle membrane material, then EUV transmission is high, but the nanotubes are vulnerable to hydrogen plasma damage due to crystalline defects
Solution Approach 1:
The patent applies composite materials by combining carbon nanotubes with protective coating layers (such as silicon nitride, aluminum oxide, or other dielectric materials) to create a hybrid structure. The carbon nanotube core maintains high EUV transmission while the protective coating layers provide resistance to hydrogen plasma etching, thus resolving the contradiction between transmission and plasma resistance.
Solution Approach 2:
The patent uses thin film protective coatings deposited on the carbon nanotube surface. These thin films act as protective shells that shield the nanotube from hydrogen plasma while being thin enough to maintain high EUV transmission. The coating thickness is optimized to balance protection and transmission requirements.
2Reliability
If protective coating is applied to carbon nanotubes, then resistance to hydrogen plasma etching is improved, but EUV transmittance may decrease
Solution Approach 1:
The patent employs ultra-thin protective coating layers with precisely controlled thickness (typically nanometer scale) to minimize EUV transmission loss while providing sufficient plasma protection. The thin film structure allows EUV photons to pass through with minimal attenuation while still forming an effective barrier against hydrogen plasma etching.
Solution Approach 2:
The patent optimizes parameters such as coating thickness, material composition, and layer structure to achieve the desired balance between plasma resistance and EUV transmission. By adjusting these parameters, the protective coating provides maximum protection with minimum impact on transmission performance.
3Duration of action of stationary object
If multilayer protective coating is applied to carbon nanotubes, then durability in hydrogen plasma environment is extended, but device complexity increases
Solution Approach 1:
The patent divides the protective coating into multiple functional layers, each with specific purposes (e.g., adhesion layer, protective layer, barrier layer). This segmentation allows each layer to be optimized for its specific function while collectively providing comprehensive protection, thereby extending durability without excessive complexity.
Solution Approach 2:
The patent designs multilayer coatings where each layer serves multiple functions simultaneously. For example, a single coating layer may provide adhesion, mechanical protection, and plasma barrier functions, reducing the total number of layers needed and simplifying the overall structure while maintaining durability.
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 multilayer coating reduces hydrogen plasma damage, improving the reliability and extending the lifespan of CNT-based pellicle membranes in EUV lithography systems.
Implementation Method 1
a hydrogen permeation barrier layer over the stress control layer
Implementation Method 2
a stress control layer
Data Source
AI summary
A pellicle comprising a pellicle membrane with improved stability to hydrogen plasma is provided. The pellicle membrane includes a network of a plurality of carbon nanotubes. At least one carbon nanotube of the plurality of carbon nanotubes is surrounded by a multilayer protective coating that includes a stress control layer and a hydrogen permeation barrier layer over the stress control layer. The stress control layer and the hydrogen permeation barrier layer independently include an Me-containing nitride or an Me-containing oxynitride with Me selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and combinations thereof. The Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration.