EUV Mask Blank Hard Mask Materials for Antimony Absorbers

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Solution Overview

Problem

Next-generation absorber materials for EUV mask blanks, such as antimony-containing materials, pose challenges during etching processes due to inadequate etch selectivity with respect to hard mask layers, necessitating the development of suitable hard mask materials for EUV mask blanks.

Innovation Solution

The use of hard mask materials like CrO, CrON, TaNi, TaRu, and TaCu in conjunction with an antimony-containing absorber layer, which provides etch selectivity ranging from 3:1 to 50:1, allowing for precise control during the etching process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antimony-containing absorber materials are used in EUV mask blanks, then the absorber performance is improved, but the etch selectivity with respect to hard mask layers deteriorates

Engineering Contradiction:

Improveabsorber performanceVSAvoidetch selectivity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the hard mask layer by incorporating specific elements ( tungsten, molybdenum, tantalum, niobium, or their oxides/nitrides) to achieve optimal etch selectivity against antimony-containing absorber materials while maintaining the required absorber performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite hard mask materials consisting of transition metals (W, Mo, Ta, Nb) and their compounds (oxides, nitrides) combined with antimony-containing absorber materials to achieve the desired etch selectivity ratio of at least 3:1, resolving the contradiction between absorber performance and etch selectivity

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional hard mask materials are used with antimony-containing absorber layers, then the manufacturing process is simplified, but the etching control and pattern fidelity deteriorate

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidetching control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent optimizes the composition parameters of the hard mask layer by selecting specific transition metals and their compounds to achieve the required etch selectivity, thereby improving etching control and pattern fidelity while maintaining manufacturing feasibility

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

This solution ensures reliable etching of EUV mask blanks with improved etch selectivity, enhancing the manufacturing process by maintaining the integrity of the multilayer stack and absorber layer, thereby improving the reflectivity and pattern formation in extreme ultraviolet lithography.

Implementation Method 1

a reflective multilayer stack 12 on a substrate 14, which reflects EUV radiation at unmasked portions by Bragg interference

Methodology Applied

Scientific EffectBragg interference: Bragg Diffraction

Data Source

PatentUS11556053B2Extreme ultraviolet mask blank hard mask materials

Publication Date: 2023.01.17 APPLIED MATERIALS INC

AI summary

Extreme ultraviolet (EUV) mask blanks, methods for their manufacture and production systems therefor are disclosed. The EUV mask blanks comprise a substrate; a multilayer stack of reflective layers on the substrate; a capping layer on the multilayer stack of reflecting layers; an absorber layer on the capping layer, the absorber layer comprising an antimony-containing material; and a hard mask layer on the absorber layer, the hard mask layer comprising a hard mask material selected from the group consisting of CrO, CrON, TaNi, TaRu and TaCu.