CNT Pellicle Protective Coating for EUV Hydrogen Radical Resistance
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Solution Overview
Problem
Existing pellicle membranes for EUV lithography are challenged by the need for materials with high transmission and stability at EUV wavelengths, and their lifetime is limited by exposure to hydrogen radicals/ions generated during exposure, necessitating improved protection.
Innovation Solution
A carbon nanotube (CNT) pellicle membrane is covered with a protective film deposited using plasma enhanced atomic layer deposition (PEALD) to shield against hydrogen radicals/ions, enhancing durability and extending the membrane's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbon nanotube pellicle membrane is used for EUV lithography, then high transmission and mechanical stability are achieved, but the membrane lifetime is limited by exposure to hydrogen radicals/ions
Solution Approach 1:
A protective film is deposited on the carbon nanotube pellicle membrane to serve as an intermediary layer between the membrane and the harmful hydrogen radicals/ions. This protective film absorbs the harmful effects of the radicals and ions, preventing them from degrading the membrane and thus extending its lifetime while maintaining EUV transmission.
2Reliability
If a protective film is deposited on the pellicle membrane to shield against hydrogen radicals/ions, then durability is enhanced, but transmission may be reduced
Solution Approach 1:
The thickness and material composition of the protective film are optimized to achieve the right balance between protection and transmission. By controlling the film parameters (thickness, density, material), sufficient protection against hydrogen radicals/ions is provided while minimizing the impact on EUV light transmission.
Solution Approach 2:
The pellicle membrane is constructed as a composite structure combining carbon nanotubes with a protective film material that is transparent to EUV radiation. This composite approach allows the carbon nanotube base layer to provide mechanical stability and the protective film to provide chemical resistance, while both layers are selected to maintain high EUV transmission.
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 protective film provides effective shielding, prolonging the CNT pellicle membrane's lifetime and maintaining high transmission and mechanical stability under EUV exposure conditions.
Implementation Method 1
a protective film deposited using plasma enhanced atomic layer deposition (PEALD) to shield against hydrogen radicals/ions
Implementation Method 2
igniting a plasma in a deposition chamber
Data Source
AI summary
A method of forming a pellicle includes forming a protective film surrounding a membrane to form a pellicle membrane using a plasma enhanced atomic layer deposition (PEALD) process, in which the membrane includes a network of carbon nanotubes, the PEALD process is performed by a plurality of cycles, and each of the cycles includes igniting a plasma in a deposition chamber, after igniting the plasma, introducing a silicon-based precursor into the deposition chamber, purging the silicon-based precursor, introducing a reactant gas into the deposition chamber, and purging the reactant gas, placing the pellicle membrane on a filter membrane, transferring the pellicle membrane from the filter membrane to a pellicle border, attaching the pellicle border to a pellicle frame, and mounting the pellicle frame onto a photomask comprising a pattern region.