Positive Resist Composition for Immersion Lithography

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Solution Overview

Problem

Conventional fluorine-containing polymeric compounds used in chemically amplified positive resists for immersion lithography suffer from excessive outgassing and inadequate dry etching resistance, and their hydrophobic surface modifications do not sufficiently enhance water tracking ability, affecting exposure speed and productivity.

Innovation Solution

A positive resist composition incorporating a polymeric compound with specific structural units derived from acrylate esters and a fluorine-containing resin, which increases alkali solubility upon acid exposure, forming a highly hydrophobic resist film surface to improve water tracking and etching resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If fluorine-containing polymeric compounds are used as base resin for chemically amplified positive resist, then water repellency and transparency are improved, but outgassing increases and dry etching resistance deteriorates

Engineering Contradiction:

ImprovetransparencyVSAvoiddry etching resistance

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent uses a composite resin system combining fluorine-containing polymeric compound with specific acid-labile groups (methoxymethyl, tert-butyl, or tert-butyloxycarbonyl) and fluorine-containing cyclic carbonate units. This composite structure provides both water repellency and transparency while maintaining acceptable etching resistance through the synergistic effect of different functional groups.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces fluorine-containing cyclic carbonate units with specific structural characteristics (R1 and R2 representing hydrogen or alkyl groups) at particular positions within the polymer chain. This localized modification provides etching resistance specifically where needed while preserving the overall water repellency and transparency properties of the fluorine-containing matrix.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If fluorine-containing polymeric compounds are used as base resin for chemically amplified positive resist, then water repellency is improved, but outgassing increases

Engineering Contradiction:

Improvewater repellencyVSAvoidoutgassing

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the chemical structure parameters of the fluorine-containing polymeric compound by incorporating specific acid-labile groups and fluorine-containing cyclic carbonate units. This changes the thermal and chemical stability parameters, reducing outgassing while preserving water repellency through the optimized fluorine atom arrangement and molecular structure.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If hydrophobic surface modification is applied to resist film, then water tracking ability is improved, but exposure speed and productivity are affected

Engineering Contradiction:

Improvewater tracking abilityVSAvoidexposure speed

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent optimizes the hydrophobicity parameter of the resist film surface by controlling the concentration and distribution of fluorine-containing groups and acid-labile groups. This creates an optimal balance where water tracking ability is enhanced without excessive surface energy that would slow down exposure processing, thus improving productivity.

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 composition enables the formation of resist films with enhanced hydrophobicity and etching resistance, improving exposure speed and productivity by reducing substance elution and enhancing lithography properties.

Implementation Method 1

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

Methodology Applied

Scientific EffectPhotochemical reaction: Photodissociation

Implementation Method 2

the fluorine-containing compound component (F)... forming a highly hydrophobic resist film surface

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentUS8349534B2Positive resist composition and method of forming resist pattern

Publication Date: 2013.01.08 TOKYO OHKA KOGYO CO LTD

AI summary

A positive resist composition including:a polymeric compound (A1) having a structural unit (a0) that contains a “cyclic group containing —SO2—” on the side chain terminal, and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group;an acid generator component (B); anda fluorine-containing resin component having a structural unit (f1) represented by general formula (f1-0):wherein R represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; Q0 represents a single bond or a divalent linking group having a fluorine atom; and RX0 represents an acid dissociable, dissolution inhibiting group-containing group which may contain a fluorine atom, with the provision that at least one fluorine atom is contained in formula (f1-0).