Cycloaliphatic Acid Generator for High-Resolution Resist Patterns

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Solution Overview

Problem

Current acid generators for chemically amplified resists, particularly those using perfluoroalkylsulfonic acid ions, face challenges in safely reproducing fine patterns due to the difficulty in decomposing perfluoroalkyl chains and concerns about bioaccumulation, while also requiring improved transparency for shorter wavelength light sources.

Innovation Solution

A novel acid generator compound represented by specific chemical formulas, including an anionic cyclic group with an ester linkage and an acid generator component that changes solubility in an alkali developing solution upon exposure, enabling the formation of resist patterns with high resolution and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If perfluoroalkylsulfonic acid ions are used as acid generators, then pattern reproduction capability is improved, but safety deteriorates due to difficulty in decomposition and bioaccumulation concerns

Engineering Contradiction:

Improvepattern reproduction capabilityVSAvoidsafety

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the problematic perfluoroalkyl chain from the acid generator structure and replaces it with a cycloaliphatic hydrocarbon group. This substitution removes the harmful perfluoroalkyl moiety while retaining the acid generator's functional properties, thereby improving safety without sacrificing pattern reproduction capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical structure parameters of the anion moiety from perfluoroalkyl chains to cycloaliphatic hydrocarbon groups with specific ring structures and carbon atom counts (3-20 carbon atoms). This parameter change maintains the acid generation function while eliminating the decomposition difficulty and bioaccumulation issues associated with perfluoroalkyl chains

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If PHS-based resins are used as base resins, then transparency to KrF excimer laser is improved, but resolution for shorter wavelength light deteriorates due to aromatic ring absorption

Engineering Contradiction:

Improvetransparency to KrF excimer laserVSAvoidresolution for shorter wavelength light

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the base resin by replacing aromatic ring-containing PHS structures with acrylic resin structures containing aliphatic polycyclic groups. This parameter change reduces light absorption in the shorter wavelength range while maintaining adequate transparency for KrF excimer laser, thereby improving resolution without completely sacrificing KrF transparency

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If perfluoroalkyl chains are made long to suppress acid diffusion, then pattern resolution is improved, but decomposition difficulty increases and safety worsens

Engineering Contradiction:

Improvepattern resolutionVSAvoiddecomposition difficulty

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the perfluoroalkyl chain entirely from the molecular structure and replaces it with a cycloaliphatic hydrocarbon group. This removal eliminates the decomposition difficulty associated with long perfluoroalkyl chains while maintaining acid diffusion suppression through the cyclic structure's steric effects

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent adopts a shorter-lived, more decomposable cycloaliphatic hydrocarbon group instead of the persistent perfluoroalkyl chain. The cycloaliphatic structure is designed to be more environmentally friendly and easier to decompose while still providing the necessary acid diffusion control for high-resolution patterning

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 novel acid generator compound allows for the formation of resist patterns with high resolution and safety, addressing the limitations of existing acid generators by enhancing pattern reproduction capabilities and safety while being suitable for use with shorter wavelength light sources.

Implementation Method 1

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

Methodology Applied

Scientific EffectPhotochemical reaction: Photodissociation

Data Source

PatentUS8252505B2Compound and method of producing same, acid generator, resist composition, and method of forming resist pattern

Publication Date: 2012.08.28 TOKYO OHKA KOGYO CO LTD

AI summary

A resist composition including a base component (A) that exhibits changed solubility in an alkali developing solution under the action of acid, and an acid generator component (B) that generates acid upon exposure, wherein the acid generator component (B) includes an acid generator (B1) consisting of a compound represented by general formula (b1-2) shown below:[Chemical Formula 1]A+Z− (b1-2)wherein A+ represents an organic cation; and Z− represents an anionic cyclic group, wherein the cyclic group includes an ester linkage within the ring structure, two mutually different groups are bonded to the ring structure, one of these groups includes an ester linkage in which a carbon atom that constitutes part of the ester linkage is bonded directly to the ring structure, and the other group includes an anion moiety.