Core-Shell Pellicle Structure for EUV Lithography Heat Stability

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Solution Overview

Problem

EUV lithography pellicles face challenges such as distortion, cracking, and breaking due to high temperatures and EUV-induced hydrogen and oxygen plasma etching, which affect EUV transmittance and reflectivity, and existing materials like carbon nanotubes lack thermal stability and uniformity.

Innovation Solution

A pellicle structure is formed using a core-shell configuration where single or double wall carbon nanotubes are wrapped with inorganic or ceramic nanotubes, creating a network membrane with enhanced mechanical strength and EUV transmittance, utilizing materials like boron nitride nanotubes and transition metal dichalcogenides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If carbon nanotubes are used as pellicle material, then EUV transmittance is improved, but thermal stability and mechanical strength deteriorate at high temperatures

Engineering Contradiction:

ImproveEUV transmittanceVSAvoidthermal stability

Core Design Contradiction:

Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent uses composite materials by combining carbon nanotubes with inorganic nanotubes (such as boron nitride nanotubes) to create a hybrid structure. The carbon nanotube core provides high EUV transmittance, while the inorganic nanotube shell provides thermal stability and resistance to plasma etching, thus resolving the contradiction between EUV transmittance and thermal stability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating a core-shell structure where different materials serve different functions in different regions. The inner carbon nanotube core is optimized for EUV transmittance, while the outer inorganic nanotube shell is optimized for thermal stability and chemical resistance, allowing each material to perform its best in its designated zone

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If carbon nanotubes are used as pellicle material, then EUV transmittance is improved, but mechanical strength and uniformity deteriorate

Engineering Contradiction:

ImproveEUV transmittanceVSAvoidmechanical strength

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The patent combines carbon nanotubes with inorganic nanotubes in a composite structure where the inorganic shell provides enhanced mechanical strength and structural uniformity while the carbon nanotube core maintains high EUV transmittance, thus resolving the contradiction between transmittance and mechanical strength

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If existing pellicle materials are used, then manufacturing is simplified, but resistance to plasma etching and thermal degradation deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidresistance to plasma etching

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by protecting only the critical carbon nanotube regions with inorganic nanotube shells, providing plasma etching resistance where needed while maintaining the overall simplicity of the manufacturing process through a straightforward core-shell formation approach

Inventive Principle:

Principle #3Local quality

4Illumination intensity

If pellicle membrane is made thinner to improve EUV transmittance, then optical performance is improved, but mechanical strength and structural stability deteriorate

Engineering Contradiction:

ImproveEUV transmittanceVSAvoidstructural stability

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The patent uses composite materials where the thin carbon nanotube core provides minimal EUV absorption, and the inorganic nanotube shell provides structural support and mechanical strength, enabling the membrane to be thin enough for high transmittance while remaining mechanically stable

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 pellicle structure achieves high EUV transmittance (>96.5%) and thermal stability up to 800-900°C, minimizing sagging and maintaining pattern imaging quality.

Implementation Method 1

single or double wall carbon nanotubes are wrapped with inorganic or ceramic nanotubes, creating a network membrane

Methodology Applied

Scientific EffectNanotube wrapping:

Implementation Method 2

a pellicle having a high transparency in the EUV wavelength region

Methodology Applied

Scientific EffectEUV transmittance:

Implementation Method 3

thermal stability up to 800-900°C

Methodology Applied

Scientific EffectThermal stability:

Implementation Method 4

resistance to plasma etching

Methodology Applied

Scientific EffectPlasma resistance:

Data Source

PatentUS20250328070A1Pellicle structure for EUV lithography and methods of manufacturing thereof

Publication Date: 2025.10.23 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of forming a pellicle includes growing carbon nanotubes (CNTs), wrapping the CNTs with one or more nanotubes made of a different material, and removing the CNTs. The CNTs can be grown over a filter and the filter can be subsequently removed. The CNTs can be contacted with a frame. The different materials include one or more of boron nitride, hexagonal boron nitride (h-BN), SiC, MoS2, MoSe2, WS2, WSe2, SnS2, SnS, ZrO2, ZrO, and TiO2.