EUV Mask Absorber Materials to Reduce M3D Effects

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Solution Overview

Problem

EUV mask blanks with thick absorber layers suffer from high M3D (Mask 3-Dimensional) effects and increased exposure energy consumption, which hinder the high-volume manufacturing of extreme ultraviolet lithography.

Innovation Solution

Employing high-K materials, such as Ru-based alloys, as absorber layers in EUV mask blanks to reduce thickness, thereby reducing M3D effects and exposure energy, and improving image quality through enhanced aerial image contrast and normalized image log slope.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick absorber layers are used in EUV mask blanks, then absorption of EUV light is improved, but M3D effects and exposure energy consumption increase

Engineering Contradiction:

Improveabsorption of EUV lightVSAvoidM3D effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter (extinction coefficient) by using high-K materials with higher absorption coefficients than traditional TaBN or TaN. This allows achieving the same absorption effect with a thinner layer, thereby reducing M3D effects while maintaining reliable EUV light absorption

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material solutions by using Ru-based alloys (such as PtRu, IrRu, OsRu, HfRu, RhRu) that combine ruthenium with other metals to achieve high extinction coefficients. These composite materials provide superior absorption properties compared to single-element materials

Inventive Principle:

Principle #40Composite materials

2Reliability

If thick absorber layers are used in EUV mask blanks, then absorption of EUV light is improved, but exposure energy consumption increases

Engineering Contradiction:

Improveabsorption of EUV lightVSAvoidexposure energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

By changing the material parameter (extinction coefficient) to use high-K materials, the patent reduces the required absorber thickness. This thinner absorber layer reduces the energy required for exposure while maintaining adequate absorption, thereby lowering exposure energy consumption

Inventive Principle:

Principle #35Parameter changes

3Reliability

If thick absorber layers are used in EUV mask blanks, then absorption of EUV light is improved, but image quality deteriorates

Engineering Contradiction:

Improveabsorption of EUV lightVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter (extinction coefficient) to use high-K materials, which enables thinner absorber layers that reduce M3D effects. This improvement in dimensional accuracy directly enhances manufacturing precision and image quality by minimizing distortion in the projected pattern

Inventive Principle:

Principle #35Parameter 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 use of high-K materials in EUV mask blanks reduces M3D effects, lowers exposure energy, and enhances image quality by increasing aerial image contrast and reducing mask error enhancement factors.

Implementation Method 1

an absorber having extinction coefficient at an EUV wavelength that exceeds extinction coefficients of TaBN and TaN at the EUV wavelength

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS20250362584A1Lithography mask having high extinction coefficient absorber and related systems and methods

Publication Date: 2025.11.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An extreme ultraviolet (EUV) mask and method of forming an EUV mask are provided. The method includes forming a mask layer on a semiconductor wafer, generating extreme ultraviolet (EUV) light by a lithography exposure system, forming patterned EUV light by patterning the EUV light by a mask including an absorber having extinction coefficient at an EUV wavelength that exceeds extinction coefficients of TaBN and TaN at the EUV wavelength, and exposing the mask layer by the patterned EUV light.