Fluorinated EUV Underlayer for Lower-Dose Resist Patterning

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Solution Overview

Problem

EUV photoresist materials require high dosages to achieve desired contrast, leading to issues like high line edge roughness, line width roughness, and poor local critical dimension uniformity, which increases cost and reduces throughput.

Innovation Solution

An underlayer comprising carbon and fluorine is used, with fluorine selectively diffusing into exposed regions of the resist layer, enhancing deprotection reactions and allowing for reduced EUV doses while maintaining pattern clarity and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high EUV dosage is used to achieve desired contrast, then pattern contrast is improved, but line edge roughness increases and throughput decreases

Engineering Contradiction:

Improvepattern contrastVSAvoidthroughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

An underlayer comprising carbon and fluorine is introduced between the substrate and the EUV photoresist layer. This underlayer acts as an intermediary that enhances the chemical conversion of the photoresist layer through fluorine diffusion, allowing reduced EUV dosage while maintaining desired pattern contrast and reducing line edge roughness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The underlayer composition is specifically designed with carbon and fluorine elements, where the fluorine concentration and bonding state are controlled to optimize the chemical conversion enhancement. By adjusting the chemical parameters of the underlayer, the photoresist layer achieves better contrast at lower EUV doses, improving both precision and throughput.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If high EUV dosage is used to achieve desired contrast, then pattern contrast is improved, but manufacturing cost increases

Engineering Contradiction:

Improvepattern contrastVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The underlayer is formed using atomic layer deposition (ALD) with controlled precursor dosing to achieve the desired carbon and fluorine composition. By optimizing the deposition parameters and underlayer thickness, the process achieves high pattern contrast at reduced EUV doses, lowering overall manufacturing costs despite the added underlayer formation step.

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 approach improves throughput by reducing EUV dosage needs, minimizing scum formation, and enhancing pattern transfer quality, thus lowering costs and improving semiconductor device yield.

Implementation Method 1

fluorine from the underlayer diffuses into the resist layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS20250385093A1Underlayer with fluorine for extreme ultraviolet (EUV) lithography

Publication Date: 2025.12.18 APPLIED MATERIALS INC

AI summary

Embodiments described herein relate to a method that includes forming an underlayer over a substrate, wherein the underlayer is an extreme ultraviolet (EUV) resist that includes carbon and fluorine. In an embodiment, the method includes forming a resist layer over the underlayer, wherein the resist layer is an EUV chemically amplified resist (CAR). In an embodiment, the method includes exposing the resist layer and the underlayer to EUV electromagnetic radiation, wherein fluorine from the underlayer diffuses into the resist layer. In an embodiment, the method includes developing the resist layer.