Free-Standing HARM Pellicle Films for Uniform EUV Filtration

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Solution Overview

Problem

Defects in EUV pellicle films hinder the adoption of extreme ultraviolet lithography, necessitating advanced particle filters with improved precision and uniformity.

Innovation Solution

A method involving stepwise deposition of high aspect ratio molecular structures (HARM-structures) onto a porous filter and then transferring them to a frame, followed by additional deposition on the free-standing film to form a pellicle film, reducing defects and enhancing uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional pellicle film is used in EUV lithography, then the photomask is protected from defects, but defects in printing remain due to insufficient particle filtration precision

Engineering Contradiction:

Improveparticle filtration precisionVSAvoidprinting precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The pellicle film is segmented into multiple functional layers: a porous support layer and multiple HARM structure layers deposited sequentially. This segmentation allows each layer to perform specific functions - the porous layer provides mechanical support while the HARM layers provide particle filtration, achieving both structural integrity and high filtration precision without compromising printing quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure combining porous support material with high aspect ratio molecular structures (HARM). This composite approach integrates the mechanical properties of the porous support with the filtration capabilities of HARM structures, achieving both defect protection and printing precision simultaneously

Inventive Principle:

Principle #40Composite materials

2Reliability

If a thick pellicle film is used to improve particle filtration, then filtration capability increases, but transmittance uniformity decreases

Engineering Contradiction:

Improveparticle filtration capabilityVSAvoidtransmittance uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The HARM structures are deposited with controlled local density and distribution on the porous support. The local quality of the film is optimized by controlling the deposition parameters to achieve uniform transmittance across the film while maintaining sufficient thickness for particle filtration in the vertical direction

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solution moves from a single thick layer to multiple thin layers deposited sequentially. By distributing the filtration function across multiple dimensions (multiple layers), the film achieves sufficient filtration capability while maintaining transmittance uniformity within each individual layer, avoiding the uniformity issues associated with single thick layers

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If HARM structures are deposited directly onto a frame, then the free-standing film is formed, but the film lacks sufficient mechanical support and uniformity

Engineering Contradiction:

Improvefree-standing film formationVSAvoidfilm uniformity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

A porous support layer is introduced as an intermediary substrate during the HARM structure deposition process. This intermediary provides mechanical support and a uniform surface for HARM deposition, ensuring film uniformity. After deposition, the porous support is removed, leaving the HARM structures as a free-standing film that maintains the uniformity achieved during the supported deposition phase

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method results in a free-standing pellicle film with a transmittance difference of at most 1% and significantly fewer defects, improving mechanical properties and particle filtration capabilities.

Implementation Method 1

depositing a first portion of HARM-structures onto a porous filter to form a film of HARM-structures on the porous filter

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

transferring the film of HARM-structures from the porous filter to a frame to form a free-standing film of HARM-structures attached to the frame

Methodology Applied

Scientific EffectMechanical transfer:

Implementation Method 3

depositing a second portion of HARMS-structures onto the free-standing film of HARM-structures attached to the frame to form the free-standing pellicle film

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS20250271749A1A free-standing pellicle film comprising harm-structures

Publication Date: 2025.08.28 CANATU FINLAND OY

AI summary

A method for forming a free-standing pellicle film including high aspect ratio molecular structures (HARM-structures) is disclosed. The method includes depositing a first portion of HARM-structures onto a porous filter to form a film of HARM-structures on the porous filter, transferring the film of HARM-structures from the porous filter to a frame to form a free-standing film of HARM-structures attached to the frame, and depositing a second portion of HARMS-structures onto the free-standing film of HARM-structures attached to the frame to form a free-standing pellicle film of HARM-structures attached to the frame.