Fluorinated Polymer Resist Additive for ArF Immersion Lithography

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Solution Overview

Problem

ArF immersion lithography faces issues with resist components being leached out and water penetration into the resist film, leading to pattern profile changes and defects, and existing solutions either require costly protective coatings or compromise on water repellency and scanning speed.

Innovation Solution

A resist composition incorporating a polymer with recurring units having fluorinated ester groups at the distal end of side chains, which enhances water repellency and water slip, reducing development defects and eliminating the need for protective coatings, while maintaining high-speed scanning capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective coating is applied between the resist film and water to prevent leaching and penetration, then pattern profile stability improves, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvepattern profile stabilityVSAvoidcoating structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The resist composition itself provides protective functionality through the fluorinated polymer additive that segregates to the surface, creating water repellency and preventing acid leaching without requiring a separate protective coating layer. The resist formulation serves its own protection needs.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention changes the chemical composition parameters of the resist by incorporating fluorinated polymer additives with specific properties (low surface energy, water repellency). This modifies the surface characteristics of the resist to provide protection against water penetration and acid leaching.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If fluorinated compounds are used for protective coating to achieve water repellency, then water repellency improves, but environmental impact and cost increase due to fluorocarbon solvents

Engineering Contradiction:

Improvewater repellencyVSAvoidenvironmental impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention uses a fluorinated polymer additive that is incorporated into the resist formulation and provides the necessary water repellency function. This eliminates the need for separate fluorocarbon-based protective coating materials and their associated environmentally harmful solvents.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The fluorinated polymer additive acts as an intermediary substance within the resist composition that provides water repellency at the resist-water interface, replacing the need for separate protective coating materials that would require environmentally harmful fluorocarbon solvents for application and removal.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If scanning speed is increased for high-speed scanning, then productivity improves, but water droplet formation and defects increase

Engineering Contradiction:

Improvescanning speedVSAvoidpattern defect rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The fluorinated polymer additive is incorporated into the resist composition before exposure, where it segregates to the surface and establishes water repellency properties in advance. This preliminary preparation prevents water droplet formation during high-speed scanning by creating a hydrophobic barrier that repels water before it can accumulate into defects.

Inventive Principle:

Principle #10Preliminary action

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 excellent water repellency and water slip, reducing development defects and enabling high-speed scanning without the need for protective coatings, thus improving the reliability and efficiency of ArF immersion lithography.

Implementation Method 1

a fluorinated polymer additive which segregates at the resist surface and exhibits water repellency

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 2

the fluorinated polymer additive segregates at the resist surface during resist film formation

Methodology Applied

Scientific EffectSurface segregation:

Implementation Method 3

recurring units having fluorinated ester groups at the distal end of side chains, which enhances water repellency and water slip

Methodology Applied

Scientific EffectSurface energy reduction: Surface Tension

Implementation Method 4

a compound capable of generating an acid upon exposure to high-energy radiation

Methodology Applied

Scientific EffectPhotoacid generation: Photopolymerisation

Data Source

PatentUS8313886B2Resist composition and patterning process

Publication Date: 2012.11.20 SHIN ETSU CHEMICAL CO LTD

AI summary

An additive polymer comprising recurring units of formula (1) is added to a resist composition comprising a base resin, a photoacid generator, and an organic solvent. R1 is hydrogen or methyl, R2 is alkylene or fluoroalkylene, and R3 is fluoroalkyl. The additive polymer is highly transparent to radiation with wavelength of up to 200 nm. Water repellency, water slip, acid lability, hydrolysis and other properties of the polymer may be adjusted by a choice of polymer structure.