Pellicle Membrane Strength EUV Transmission

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing pellicle membranes in EUV lithographic apparatuses face challenges in maintaining transparency and strength, particularly when exposed to EUV radiation, and struggle with contamination protection and alignment due to similar reflectivity with patterning devices.

Innovation Solution

A pellicle membrane comprising metal silicide with a reinforcing network of carbon nanotubes, which strengthens the membrane while maintaining EUV transparency, and a border stack with selective reflectivity to enhance contrast for alignment purposes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a pellicle membrane is made thinner to maintain EUV transparency, then EUV radiation transmission is improved, but the membrane strength and structural stability deteriorate

Engineering Contradiction:

ImproveEUV transmissionVSAvoidmembrane strength

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The pellicle membrane uses a composite structure combining metal silicide matrix with carbon nanotube reinforcing network. The carbon nanotubes provide exceptional mechanical strength while the metal silicide matrix maintains EUV transparency, allowing the membrane to be thin yet strong enough for EUV lithography applications.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The reinforcing network is distributed locally throughout the metal silicide matrix rather than uniformly throughout. This localized reinforcement strategy maintains EUV transmission by minimizing material in the radiation path while providing necessary structural strength where needed.

Inventive Principle:

Principle #3Local quality

2Strength

If a reinforcing network is added to strengthen the pellicle membrane, then membrane strength is improved, but EUV radiation transmission deteriorates

Engineering Contradiction:

Improvemembrane strengthVSAvoidEUV transmission

Core Design Contradiction:

StrengthVSIllumination intensity

Solution Approach 1:

The reinforcing network is configured with windows or gaps between the nanotube structures, creating a porous-like architecture that allows EUV radiation to pass through while the nanotube framework provides mechanical reinforcement. The open structure minimizes radiation attenuation while maintaining strength.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

3Reliability

If the pellicle membrane surface is modified to improve contamination resistance, then contamination protection is improved, but alignment precision deteriorates due to similar reflectivity with patterning devices

Engineering Contradiction:

Improvecontamination protectionVSAvoidalignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The metal silicide surface is selectively nitridated only in certain regions or to certain depths, creating local variations in reflectivity. This allows the pellicle to maintain contamination resistance from the metal silicide surface while having distinct reflectivity characteristics in specific areas that enable precise alignment with patterning devices.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The nitridation process modifies the optical reflectivity characteristics of the metal silicide surface, creating a detectable optical contrast between the pellicle and patterning device. This reflectivity difference acts like an optical signature that enables precise alignment and positioning during lithography operations.

Inventive Principle:

Principle #32Color changes

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 solution provides improved strength and EUV transmission with minimal reduction in EUV radiation transmission, and facilitates easier alignment by creating a distinct contrast between the pellicle assembly and patterning device, reducing contamination impact and improving lithographic apparatus performance.

Implementation Method 1

the pellicle membrane comprises metal silicide and a reinforcing network

Methodology Applied

Scientific EffectCarbon nanotubes: Carbon Nanotubes

Implementation Method 2

the behaviour of the surface of the pellicle when exposed to conditions such as EUV radiation is unaffected by the reinforcing network

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20250004362A1Pellicle membrane

Publication Date: 2025.01.02 ASML NETHERLANDS BV

AI summary

A pellicle membrane for a lithographic apparatus, wherein the pellicle membrane includes metal silicide and a reinforcing network. The reinforcing network can be located between metal silicide layers. The reinforcing network can be irregular. The reinforcing network includes windows with a maximum dimension of up to 20 microns. The reinforcing network includes windows having an average size of at least 5 microns.