Amorphous EUV Mask Capping Layer Against Chemical Diffusion

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Solution Overview

Problem

Conventional EUV lithography masks with polycrystalline capping layers are prone to damage during processing, leading to reduced lithography performance and shortened lifespan due to chemical diffusion and hydrogen radical attack, which increases fabrication costs.

Innovation Solution

Implementing an amorphous capping layer on the EUV lithography mask to enhance durability and protect the multi-layer reflective structure, formed through processes like plasma treatment and deposition to prevent damage from chemical corrosion and hydrogen radicals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a polycrystalline capping layer is used in EUV lithography masks, then the mask can be manufactured with conventional processes, but the capping layer becomes damaged during processing due to chemical diffusion and hydrogen radical attack

Engineering Contradiction:

Improvemanufacturability of capping layerVSAvoiddurability of capping layer

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the structural parameter of the capping layer from polycrystalline to amorphous. This parameter change eliminates grain boundaries, making the material resistant to chemical diffusion and hydrogen radical attack while maintaining manufacturability through conventional deposition processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining the amorphous capping layer with the underlying multi-layer reflective structure. The amorphous material properties provide chemical resistance and durability, while the composite structure maintains the optical functionality required for EUV lithography

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If the capping layer is made more durable to resist chemical corrosion, then the mask lifespan is extended, but the fabrication process becomes more complex

Engineering Contradiction:

Improvelifespan of EUV maskVSAvoidcomplexity of fabrication process

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The amorphous capping layer serves as a sacrificial protective layer that can be easily deposited and provides long-term protection. Its simplicity and ease of deposition make it a cost-effective solution compared to more complex protective structures

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 amorphous capping layer improves lithography performance and extends the EUV mask lifespan, reducing fabrication costs by minimizing damage and maintaining reflectivity.

Implementation Method 1

formed through processes like plasma treatment and deposition to prevent damage from chemical corrosion and hydrogen radicals

Methodology Applied

Scientific EffectPlasma treatment: Plasma

Implementation Method 2

formed through processes like plasma treatment and deposition to prevent damage from chemical corrosion and hydrogen radicals

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS20260072340A1Amorphous capping layer structure for lithography mask blank

Publication Date: 2026.03.12 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A multi-layer reflective structure is disposed over a substrate. An amorphous capping layer is disposed over the multi-layer reflective structure and includes platinum (Pt), iridium (Ir), rhenium (Rh), or ruthenium (Ru) alloyed with Pt, Ir, or Rh.