Carbon Nanotube Pellicle Film for Hydrogen Plasma Resistance
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Solution Overview
Problem
Pellicle films made from carbon nanotubes produced by the super-growth method are prone to film reduction when exposed to hydrogen plasma, leading to fluctuations in exposure light transmittance and deterioration of transfer performance in EUV lithography.
Innovation Solution
A pellicle film comprising carbon nanotubes with specific linearity and packing density parameters, along with diffraction peak ratios and smoothness evaluations, to minimize film reduction under hydrogen plasma exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pellicle film made from carbon nanotubes produced by the super-growth method is used, then the film is transparent to EUV light and can prevent foreign matter adhesion, but the film experiences film reduction when exposed to hydrogen plasma, causing transmittance fluctuations and deterioration of transfer performance
Solution Approach 1:
The patent applies parameter changes by controlling the linearity parameter of carbon nanotubes to be 0.15 or less and the packing density parameter to be 0.25 or less. These specific parameter ranges optimize the film's resistance to hydrogen plasma while maintaining EUV light transmittance, thereby preventing film reduction and transmittance fluctuations during exposure
Solution Approach 2:
The patent uses carbon nanotubes as a composite material structure with specific structural characteristics (linearity and packing density). The carbon nanotube-based pellicle film combines the transparency to EUV light with controlled plasma resistance through its unique nanoscale composite structure, resolving the contradiction between initial performance and stability under plasma exposure
2Ease of manufacture
If hydrogen gas is supplied into the vacuum chamber for cleaning contamination, then in situ cleaning of the optical system is achieved, but the hydrogen plasma causes film reduction of the pellicle film, leading to transmittance fluctuations
Solution Approach 1:
The patent applies preliminary anti-action by pre-engineering the pellicle film with specific structural parameters (linearity ≤0.15, packing density ≤0.25) that provide inherent resistance to hydrogen plasma. This preliminary structural optimization prevents the harmful effect of plasma-induced film reduction before it occurs during the cleaning process, allowing hydrogen gas cleaning to proceed without compromising exposure performance
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 pellicle film maintains stable light transmittance and transfer performance by reducing the effects of hydrogen plasma, ensuring consistent exposure results.
Implementation Method 1
the hydrogen gas supplied into the vacuum chamber is considered to become hydrogen plasma by irradiation with EUV light
Data Source
AI summary
Provided is a pellicle film, which includes plural carbon nanotubes, in which an average value of linearity parameters represented by the following Formula (1) of the plurality of carbon nanotubes is 0.10 or less:linearity parameter=standard deviation Sa of a width of single tube/average value Aa of the widthFormula (1)wherein, in Formula (1), the single tube indicates one carbon nanotube included in the plural carbon nanotubes, each of the standard deviation Sa and the average value Aa is calculated based on 11 measurement values obtained by measuring a width of the single tube at intervals of 2 nm along a longitudinal direction of the single tube.