Chemically Amplified Resist Polymer for High-Resolution Patterning

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Solution Overview

Problem

Existing chemically amplified resist compositions face challenges in achieving high sensitivity, resolution, and contrast while minimizing acid diffusion, leading to issues like pattern collapse and edge roughness during the formation of small-size patterns.

Innovation Solution

A monomer and polymer with an acid labile group attached to a hydroxy group on an aromatic ring and a pentafluorosulfanyl group on adjoining carbon atoms are used to enhance solvent solubility, sensitivity, and contrast, forming resist films with improved lithography properties such as LWR, CDU, and DOF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If acid diffusion is suppressed by reducing temperature and/or time of post-exposure bake, then resolution is improved, but sensitivity and contrast are drastically reduced

Engineering Contradiction:

ImproveresolutionVSAvoidsensitivity and contrast

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the acid labile group by introducing fluorine atoms into the aromatic group, transforming it from a highly reactive tertiary ester to a moderate reactivity system. This parameter change allows the group to maintain moderate elimination reactivity while suppressing acid diffusion, thereby achieving both high resolution and high sensitivity/contrast simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite acid labile group structure combining fluorinated aromatic groups with tertiary ester groups. This composite structure leverages the acid-catalyzed elimination reactivity of the ester while the fluorinated aromatic group moderates the reactivity and suppresses acid diffusion, resolving the contradiction between resolution and sensitivity

Inventive Principle:

Principle #40Composite materials

2Reliability

If tertiary ester acid labile groups are used, then acid-catalyzed elimination reactivity is high, but acid diffusion cannot be controlled

Engineering Contradiction:

Improveelimination reactivityVSAvoidacid diffusion control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by introducing fluorine atoms at specific positions on the aromatic group of the acid labile structure. This localized modification creates a region of high electron density that moderates the acid-catalyzed elimination reactivity while maintaining overall functionality, thereby controlling acid diffusion without sacrificing elimination reactivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the chemical parameters of the aromatic group by fluorination, transforming the electronic properties to moderate the acid-catalyzed elimination reactivity. This parameter change allows the system to maintain necessary reactivity while suppressing excessive acid diffusion

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If carboxylic acids are generated from acid labile groups, then dissolution contrast is improved, but pattern collapse occurs due to swelling in alkaline developer

Engineering Contradiction:

Improvedissolution contrastVSAvoidpattern collapse resistance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the parameters of the acid labile group by using fluorinated aromatic groups instead of simple carboxylic acid generating groups. This modification produces acids with different swelling characteristics in alkaline developer, maintaining dissolution contrast while suppressing pattern collapse

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful swelling effect of carboxylic acids into a beneficial outcome by using fluorinated aromatic groups that generate acids with controlled swelling behavior. The fluorinated structure modifies the acid's interaction with the developer to maintain contrast while preventing excessive swelling that causes collapse

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 resist composition achieves high sensitivity and contrast with reduced pattern collapse, improved line width roughness, critical dimension uniformity, and depth of focus, suitable for high-energy radiation lithography processes.

Implementation Method 1

When the acid labile groups of tertiary ester form undergo acid-catalyzed deprotection reaction, carboxylic acids are generated

Methodology Applied

Scientific EffectAcid-catalyzed elimination reaction: Catalysis

Implementation Method 2

Since the carboxylic acids show a swelling behavior in alkaline developer

Methodology Applied

Scientific EffectSwelling: Absorption (physical)

Implementation Method 3

image blurs due to acid diffusion become a problem

Methodology Applied

Scientific EffectAcid diffusion: Diffusion

Data Source

PatentUS20250362602A1Monomer, polymer, chemically amplified resist composition, and pattern forming process

Publication Date: 2025.11.27 SHIN ETSU CHEMICAL CO LTD

AI summary

A polymer obtained from a monomer structured to have an acid labile group attached to a hydroxy group on an aromatic ring and a SF5 group attached to the aromatic ring, which are attached to adjoining carbon atoms, has excellent solvent solubility. A chemically amplified resist composition comprising the polymer exhibits a high sensitivity and contrast and forms a pattern of satisfactory profile having improved lithography properties such as EL, LWR, CDU and DOF.