Immersion Resist Composition for Lithography Water Tracking

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Solution Overview

Problem

Current resist materials for immersion exposure in liquid immersion lithography lack suitable hydrophobicity, leading to reduced exposure speed and productivity due to low water tracking ability, while increasing hydrophobicity adversely affects lithography properties such as resolution and sensitivity.

Innovation Solution

A resist composition comprising a base component that changes solubility in an alkali developing solution, an acid generator, and a fluorine-containing resin component with specific structural units, which enhances hydrophobicity and lithography properties, including a positive resist composition with an acid dissociable, dissolution inhibiting group to improve water tracking ability and pattern formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the hydrophobicity of the resist film is increased to improve water tracking ability, then exposure speed and productivity are improved, but lithography properties such as resolution and sensitivity deteriorate

Engineering Contradiction:

Improveexposure speedVSAvoidresolution

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a fluorinated group-containing compound that provides localized hydrophobicity at the resist-water interface without requiring the entire resist film to be highly hydrophobic. This localized modification improves water tracking ability and exposure speed while preserving the bulk resist properties needed for high resolution and sensitivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite resist system by combining a base resin (acrylic resin with specific structural units) with a fluorinated group-containing compound. This composite structure allows the fluorinated compound to provide surface hydrophobicity for improved water tracking, while the base resin maintains the lithography properties including resolution and sensitivity.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If conventional resist materials are used for immersion exposure, then lithography properties are maintained, but water tracking ability is insufficient leading to reduced productivity

Engineering Contradiction:

Improvelithography propertiesVSAvoidexposure speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The fluorinated group-containing compound acts as an intermediary substance that mediates between the resist film and the immersion liquid (water). It improves the interface properties by providing hydrophobicity, thereby enhancing water tracking ability and exposure speed without compromising the lithography properties provided by the base resin.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If fluorine-containing polymeric compounds are used to enhance hydrophobicity, then water tracking ability improves, but etching resistance becomes insufficient

Engineering Contradiction:

Improvewater tracking abilityVSAvoidetching resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Instead of using fluorine-containing polymeric compounds throughout the entire resist film, the patent introduces a fluorinated group-containing compound that provides localized hydrophobicity at the surface. This localized fluorine content improves water tracking ability while keeping the overall fluorine content low, thereby maintaining sufficient etching resistance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent optimizes the concentration of the fluorinated group-containing compound within a specific range (0.1-10 parts by weight per 100 parts by weight of base resin). This parameter optimization ensures adequate hydrophobicity for improved water tracking while preventing excessive fluorine content that would compromise etching resistance.

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

The resist composition achieves excellent lithography properties and suitable hydrophobicity for immersion exposure, enhancing exposure speed and productivity while maintaining resolution and sensitivity.

Implementation Method 1

a fluorine-containing resin component (C) which contains the structural unit (c1)

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 2

an acid generator component (B) which generates an acid upon exposure

Methodology Applied

Scientific EffectPhotochemical reaction: Photopolymerisation

Implementation Method 3

a base component (A) which exhibits changed solubility in an alkali developing solution under action of an acid

Methodology Applied

Scientific EffectSolubility change: Solvation

Data Source

PatentUS8900788B2Resist composition for immersion exposure and method of forming resist pattern

Publication Date: 2014.12.02 TOKYO OHKA KOGYO CO LTD

AI summary

A resist composition for immersion exposure, including: a base component (A) which exhibits changed solubility in an alkali developing solution under action of an acid, and contains no structural unit (c1) represented by the general formula (c1-1) shown below; an acid generator component (B) which generates an acid upon exposure; and a fluorine-containing resin component (C) which contains the structural unit (c1)(in the formula (c1-1), R represents a hydrogen atom, a lower alkyl group, a halogen atom, or a halogenated lower alkyl group; Rf represents a fluorinated alkyl group; and Y0 represents an alkylene group).