Carbon Nanotube Pellicle for EUV Lithography

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Solution Overview

Problem

Conventional deep ultraviolet (DUV) pellicles exhibit excessive absorption of extreme ultraviolet light and are prone to damage in the high-energy environment of extreme ultraviolet lithography (EUVL), making it challenging to find suitable pellicle designs compatible with EUVL.

Innovation Solution

A method for forming a carbon nanotube (CNT) pellicle membrane by pressing CNT films between pressing surfaces to bond overlapping CNTs, creating a free-standing membrane with enhanced mechanical strength and low EUV light absorption, using coatings and graphene flake layers to improve durability and particle blocking properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional deep ultraviolet (DUV) pellicles are used, then particle protection is provided, but excessive absorption of extreme ultraviolet light occurs and damage occurs in the high-energy environment

Engineering Contradiction:
Improveparticle protectionVSAvoidEUV light absorption
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent changes the material composition and structural parameters of the pellicle by incorporating carbon nanotubes with specific diameters (0.3-2.0 nm) and controlling the film thickness (5-50 nm) to achieve low EUV absorption while maintaining particle protection capabilities

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite pellicle structure combining carbon nanotubes with dielectric materials (such as silicon oxide, silicon nitride, or boron nitride) to achieve both particle shielding and low EUV absorption properties that neither material could achieve alone

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If conventional pellicle materials are used, then particle shielding is achieved, but the material is damaged by high-energy extreme ultraviolet light

Engineering Contradiction:
Improveparticle shieldingVSAvoidmaterial durability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent selects carbon nanotubes with specific structural parameters (diameter 0.3-2.0 nm, length 1-100 μm) and controls the film thickness (5-50 nm) to achieve both particle shielding and resistance to EUV-induced damage through optimized material parameters

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent forms composite structures with dielectric materials to enhance the reliability and durability of the pellicle in the high-energy EUV environment while maintaining particle shielding capabilities

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If thin pellicle material is used to reduce absorption, then mechanical strength is reduced, but if thick material is used, absorption increases

Engineering Contradiction:
ImproveEUV light absorptionVSAvoidmechanical strength
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The patent employs ultra-thin carbon nanotube films (5-50 nm) that maintain mechanical integrity through the inherent strength and flexibility of the carbon nanotube network structure, achieving low EUV absorption without sacrificing mechanical strength

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent combines carbon nanotubes with dielectric materials to create composite films that provide both mechanical support and low absorption properties, enabling thin-film construction with adequate mechanical strength

Inventive Principle:
Principle #40Composite materials

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 CNT pellicle membrane achieves high mechanical strength, low EUV light absorption, and improved particle protection, making it suitable for EUVL applications while withstanding the harsh scanner environment.

Implementation Method 1

overlapping or crossing CNTs of the at least one CNT film are bonded together

Methodology Applied
Scientific EffectBonding: Chemical Bonding

Data Source

PatentEP3404487B1Method for forming a carbon nanotube pellicle membrane
Publication Date: 2021.12.01 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP3404487B1 patent drawingFigure 1
  • EP3404487B1 patent drawingFigure 2
  • EP3404487B1 patent drawingFigure 3~4

AI summary

The present inventive concept relates to a method (500) for forming a carbon nanotube pellicle membrane (102, 202) for an extreme ultraviolet lithography reticle (410), the method comprising: bonding together (502) overlapping carbon nanotubes (110, 210) of at least one carbon nanotube film (104, 204a, 204b) by pressing the at least one carbon nanotube film (104, 204a, 204b) between a first pressing surface (106, 206) and a second pressing surface (108, 208), thereby forming a free-standing carbon nanotube pellicle membrane (102, 202).The present inventive concept also relates to a method for forming a pellicle (400) for extreme ultraviolet lithography and for forming a reticle system (412) for extreme ultraviolet lithography respectively.