Dry-Deposited EUV Underlayer for Lower-Dose Lithography

Solution Overview

Problem

EUV resist systems suffer from low absorption of EUV electromagnetic radiation, requiring high doses that increase exposure times and costs, and existing underlayer materials deposited with wet processes limit thickness and composition uniformity, hindering optimal patterning performance.

Innovation Solution

A dielectric underlayer comprising silicon, carbon, and hydrogen is deposited using a dry deposition process, allowing for non-uniform material composition and thin films to enhance EUV absorption and adhesion, with a graded composition through the thickness to improve patterning performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If existing EUV resist systems are used, then patterning can be achieved, but low absorption of EUV electromagnetic radiation requires large doses increasing exposure time and cost

Engineering Contradiction:

ImproveEUV radiation absorptionVSAvoidexposure time

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

An underlayer comprising silicon, carbon, oxygen, and hydrogen is introduced as an intermediary between the substrate and the EUV resist. This underlayer absorbs EUV electromagnetic radiation and generates secondary electrons that transfer to the resist, enhancing the absorption efficiency and enabling lower exposure doses while maintaining patterning quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If wet deposition processes are used for underlayer, then deposition can be achieved, but thickness and composition uniformity are limited hindering optimal patterning performance

Engineering Contradiction:

Improvethickness uniformityVSAvoiddeposition process complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The wet deposition process is replaced with a dry deposition process (physical vapor deposition). This substitution enables precise control over film thickness and composition through vapor-phase deposition, achieving superior thickness uniformity and compositional control without the limitations of wet chemical processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If wet deposition processes are used for underlayer, then deposition can be achieved, but composition uniformity is limited hindering optimal patterning performance

Engineering Contradiction:

Improvecomposition uniformityVSAvoiddeposition process complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The wet deposition process is replaced with a dry deposition process (physical vapor deposition). This substitution enables precise control over film thickness and composition through vapor-phase deposition, achieving superior thickness uniformity and compositional control without the limitations of wet chemical processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If high doses of EUV radiation are used, then resolution and patterning metrics are improved, but patterning issues arise due to resist saturation and increased exposure time

Engineering Contradiction:

ImproveresolutionVSAvoidexposure time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

An underlayer comprising silicon, carbon, oxygen, and hydrogen is introduced as an intermediary between the substrate and the EUV resist. This underlayer absorbs EUV electromagnetic radiation and generates secondary electrons that transfer to the resist, enhancing the absorption efficiency and enabling lower exposure doses while maintaining patterning quality.

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 solution reduces EUV radiation doses while maintaining high patterning quality by enhancing electron transfer and absorption, improving line edge roughness, line width roughness, and local critical dimension uniformity.

Implementation Method 1

depositing an underlayer over the hardmask layer with a dry deposition process

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

initiating a plasma in the chamber

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 3

enhancing electron transfer and absorption

Methodology Applied

Scientific EffectElectron transfer and absorption: Absorption (EM radiation)

Data Source

PatentUS20250253158A1Dry deposition of extreme ultraviolet (EUV) underlayer for lithography and patterning

Publication Date: 2025.08.07 APPLIED MATERIALS INC

AI summary

Embodiments disclosed herein comprise a method for patterning a stack. In an embodiment, the method comprises providing a substrate with a hardmask layer over the substrate, and depositing an underlayer over the hardmask layer with a dry deposition process, where the underlayer comprises silicon, carbon, oxygen, and hydrogen. In an embodiment, the method further comprises forming a resist layer over the underlayer, exposing and developing the resist layer to form a pattern in the resist layer, and transferring the pattern into the underlayer and the hardmask layer with an etch process.