EUV Lithography Optical Element Nanoparticle Protection

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Solution Overview

Problem

Existing EUV lithography systems face challenges in protecting the reflective multilayer systems from damage caused by high radiant power EUV radiation, heat, residual gases, and contaminants, which leads to degradation and reduced lifetime of the optical elements.

Innovation Solution

The integration of nanoparticles embedded into the uppermost layer of the protective layer system, which is formed by ion implantation, provides enhanced stability and absorption properties, reducing damage from EUV radiation and extending the lifetime of the optical elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective layer system is applied to the multilayer system, then the multilayer system is protected from damage by EUV radiation, heat, and contaminants, but the protective layer system itself degrades over time due to plasma formation and reactive species

Engineering Contradiction:

Improveprotection of multilayer systemVSAvoidlifetime of protective layer system

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

Nanoparticles are embedded into the protective layer system before operation to preemptively protect against degradation. The nanoparticles are positioned in advance to intercept and neutralize harmful effects such as plasma formation and reactive species attack, preventing damage before it occurs to the protective layer system

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The nanoparticles convert harmful plasma and reactive species into beneficial effects. By embedding nanoparticles that can interact with and neutralize these harmful elements, the previously damaging plasma and reactive species become part of a protective mechanism that extends the lifetime of the protective layer system

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If the protective layer system is made thicker to improve protection, then damage resistance increases, but absorption of out-of-band radiation increases and reflectivity decreases

Engineering Contradiction:

Improvedamage resistanceVSAvoidEUV radiation reflectivity

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

Instead of uniformly increasing the thickness of the entire protective layer system, nanoparticles are locally embedded at specific positions within the layer. This localized enhancement provides damage resistance only where needed, maintaining the overall thinness of the protective layer system and preserving EUV radiation reflectivity while still providing protection against harmful factors

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If ion implantation is used to embed nanoparticles, then stability and absorption properties are enhanced, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvestability of protective layer systemVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The mechanical process of nanoparticle embedding is replaced by ion implantation, which uses electromagnetic fields to accelerate ions into the protective layer system. This substitution enables precise control over nanoparticle placement and depth, enhancing stability and absorption properties while the process can be integrated into existing manufacturing workflows

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 embedded nanoparticles effectively stabilize the protective layer system against damage factors, enhance absorption of out-of-band radiation, and maintain high reflectivity for EUV radiation, thereby extending the operational lifetime of the optical elements.

Implementation Method 1

enhance absorption of out-of-band radiation

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 2

ion implantation

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Implementation Method 3

EUV radiation-reflecting multilayer system

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12306539B2Optical element, EUV lithography system, and method for forming nanoparticles

Publication Date: 2025.05.20 CARL ZEISS SMT GMBH

AI summary

An optical element (1) includes: a substrate (2), applied to the substrate (2), a multilayer system (3) which reflects EUV radiation (4), and applied to the multilayer system (3), a protective layer system (5) having an uppermost layer (5a). Nanoparticles (7) are embedded into the material of the uppermost layer (5a) of the protective layer system (5) which nanoparticles contain at least one metallic material. An EUV lithography system which includes at least one such optical element (1) designed as indicated above, and a method of forming nanoparticles (7) in the uppermost layer (5a) of the protective layer system (5) are also disclosed.