Resist Composition Acid Diffusion Control

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Solution Overview

Problem

Current chemically amplified resist compositions face challenges in maintaining high dissolution contrast and reducing edge roughness (LWR) at room temperature, particularly in negative tone pattern formation, where acid diffusion leads to dimensional changes over time due to post-exposure bake delays.

Innovation Solution

Incorporating a sulfonium or iodonium salt with a cyclic hydrocarbon-substituted amino group as a quencher, which suppresses acid diffusion at room temperature, combined with an acid generator capable of producing sulfonic acid, imide acid, or methide acid, to enhance dissolution contrast and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional amine quenchers are used to control acid diffusion, then contrast is improved, but edge roughness (LWR) increases and dissolution contrast decreases at room temperature

Engineering Contradiction:

Improvedissolution contrastVSAvoidedge roughness (LWR)

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the quencher by using sulfonium or iodonium salts with specific cyclic hydrocarbon-substituted amino groups instead of conventional amine quenchers. This parameter change enables effective acid diffusion control at room temperature while reducing edge roughness and maintaining high dissolution contrast.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite quencher system by combining sulfonium or iodonium salt structures with cyclic hydrocarbon-substituted amino groups. This composite structure provides both the acid diffusion control function and the reduced edge roughness effect simultaneously.

Inventive Principle:

Principle #40Composite materials

2Productivity

If post-exposure bake delay is extended for negative tone pattern formation, then development completeness improves, but dimensional changes increase due to acid diffusion

Engineering Contradiction:

Improvedevelopment completenessVSAvoiddimensional stability

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary anti-action by using the sulfonium or iodonium salt quencher to pre-suppress acid diffusion before the negative tone development process. This preliminary suppression prevents the harmful acid diffusion that would otherwise occur during extended post-exposure bake delays, maintaining dimensional stability while allowing complete development.

Inventive Principle:

Principle #9Preliminary anti-action

3Productivity

If acid generator concentration is increased to enhance sensitivity, then exposure sensitivity improves, but acid diffusion distance increases reducing maximum resolution

Engineering Contradiction:

Improveexposure sensitivityVSAvoidmaximum resolution

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces the sulfonium or iodonium salt quencher as an intermediary substance that mediates between the acid generator and the polymer. This intermediary captures and neutralizes acid in a controlled manner, allowing high acid generator concentration for sensitivity while preventing excessive acid diffusion that would reduce resolution.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10509314B2Resist composition and patterning process

Publication Date: 2019.12.17 SHIN ETSU CHEMICAL CO LTD

AI summary

A resist composition comprising a base polymer and a sulfonium or iodonium salt of sulfonic acid containing a cyclic hydrocarbon-substituted amino group offers dimensional stability on PPD and a satisfactory resolution.