Polymer-Bonded Onium Salt Monomer for Low-Diffusion Negative Resist

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Solution Overview

Problem

Existing chemically amplified negative resist compositions face challenges in achieving high etching resistance, organic solvent solubility, and controlling acid diffusion, leading to issues like line edge roughness and pattern collapse during miniaturization in semiconductor manufacturing.

Innovation Solution

Incorporation of a polymer-bonded acid generator using an onium salt monomer with specific structural features, such as an aromatic ring substituted with a vinyl group and a partially fluorinated sulfonate anion, to form a chemically amplified negative resist composition that enhances etching resistance and controls acid diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional resist compositions are used for miniaturization, then pattern size can be reduced, but line edge roughness increases and pattern collapse occurs

Engineering Contradiction:

Improvepattern size controlVSAvoidpattern stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the resist composition by incorporating specific onium salt monomers with polymerizable unsaturated bonds and controlling their content (1-20 mol%). This parameter optimization enables better acid diffusion control and pattern stability during miniaturization processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resist system by combining the base polymer with onium salt monomers containing polymerizable unsaturated bonds and aromatic rings. This composite structure provides both the necessary sensitivity and improved pattern stability, preventing collapse while maintaining resolution

Inventive Principle:

Principle #40Composite materials

2Productivity

If acid generator concentration is increased to improve sensitivity, then exposure sensitivity improves, but acid diffusion increases causing line edge roughness

Engineering Contradiction:

Improveexposure sensitivityVSAvoidline edge roughness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The onium salt monomer acts as an intermediary acid generator that releases acid gradually through polymerization during exposure. This intermediary mechanism provides sufficient sensitivity while controlling acid diffusion, as the acid is generated locally through the polymerization process rather than diffusing from a concentrated source

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the concentration parameter of the onium salt monomer (1-20 mol%) to balance acid generation rate with diffusion control. This parameter optimization ensures high sensitivity while maintaining sharp pattern edges by preventing excessive acid diffusion

Inventive Principle:

Principle #35Parameter changes

3Strength

If etching resistance is improved using aromatic polymer structures, then etching resistance improves, but solubility in organic solvents decreases

Engineering Contradiction:

Improveetching resistanceVSAvoidsolubility

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent applies local quality modification by incorporating aromatic rings only in specific regions (through onium salt monomer units) rather than throughout the entire polymer structure. This localized aromatic content provides necessary etching resistance while maintaining overall solubility through the rest of the polymer chain

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent optimizes the aromatic content parameter through controlled incorporation of onium salt monomers (1-20 mol%). This parameter control achieves sufficient etching resistance while preserving organic solvent solubility, as the aromatic structures are distributed rather than concentrated

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 achieves high resolution, reduced line edge roughness, and improved pattern fidelity with reduced acid diffusion, ensuring stability during pattern formation and etching processes.

Implementation Method 1

an acid generator which is decomposed to generate an acid upon exposure to light

Methodology Applied

Scientific EffectPhotoacid generation: Photodissociation

Implementation Method 2

a crosslinker which causes the polymer to crosslink in the presence of the acid serving as a catalyst

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

a polymer which is normally soluble in an aqueous alkaline developer

Methodology Applied

Scientific EffectSolubility: Solvation

Data Source

PatentUS20260010074A1Onium salt monomer, polymer, chemically amplified negative resist composition, and resist pattern forming process

Publication Date: 2026.01.08 SHIN ETSU CHEMICAL CO LTD

AI summary

Provided are an onium salt monomer which has excellent etching resistance, organic solvent solubility, and appropriate acid strength, and can generate an acid with low diffusion, a base polymer comprising a polymer-bonded acid generator using the same, a chemically amplified negative resist composition using the same, and a resist pattern forming process using the chemically amplified negative resist composition. An onium salt monomer has the formula (A1):