KrF Negative Photoresist Composition for High-Resolution Semiconductor Patterns

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Solution Overview

Problem

Conventional negative photoresists for KrF lasers face challenges in forming high-resolution, vertical cross-sectional profiles due to insufficient acid generation and profile deterioration when using short-wavelength exposure sources, necessitating improved dry etching resistance, resolution, and chemical stability for semiconductor pattern formation.

Innovation Solution

A negative photoresist composition comprising specific compounds represented by Chemical Formulas 1 to 3, derived from reactions involving 2-ethyl-2-hydroxymethyl-1,3-propanediol, bisphenol A, and 1,1,1-tri(4-hydroxyphenyl)ethane, combined with a phenol or cresol polymer resin, crosslinking agent, photoacid generator, and acid diffusion inhibitor, optimized for weight percentages to enhance transparency and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional negative photoresist composition is used for KrF laser, then the photoresist can be formed, but the photosensitive agent is unable to generate sufficient acid (H+), making it impossible to form desired shape and causing profile deterioration in finer patterns

Engineering Contradiction:

Improvepattern formation precisionVSAvoidacid generation sufficiency

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent modifies the chemical structure of the basic resin by introducing specific compounds (Chemical Formulas 1-3) with hydroxyl groups and aromatic rings, changing the chemical parameters of the photoresist system to enhance acid generation efficiency and pattern formation capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite photoresist system combining conventional basic resin with specially designed compounds (Chemical Formulas 1-3) that work synergistically to improve both acid generation and pattern profile, addressing multiple performance requirements simultaneously

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If shorter wavelength light source is used to achieve finer patterns, then pattern resolution improves, but the photoresist requires higher acid generation capability which conventional compositions cannot provide

Engineering Contradiction:

Improvepattern resolutionVSAvoidacid generation quantity

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent optimizes the chemical composition parameters by incorporating compounds with specific molecular structures (Chemical Formulas 1-3) that enhance the photoacid generation efficiency, enabling sufficient acid production even with shorter wavelength KrF laser exposure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The specially designed compounds act as intermediaries that facilitate more efficient energy transfer and acid generation from the KrF laser light to the photoresist matrix, bridging the gap between light source capabilities and pattern formation requirements

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If photoresist thickness is decreased to increase degree of integration, then device integration improves, but dry etching resistance decreases and pattern profile deteriorates

Engineering Contradiction:

Improvedegree of integrationVSAvoiddry etching resistance

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The invention develops a composite photoresist formulation where the combination of basic resin and specially designed compounds (Chemical Formulas 1-3) provides enhanced mechanical strength and dry etching resistance even in reduced thickness configurations, enabling thin photoresist layers to maintain structural integrity during etching processes

Inventive Principle:

Principle #40Composite materials

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 patterns with high transparency and resolution, suitable for semiconductor processing, even with short-wavelength exposure sources, and maintains an excellent profile, addressing the limitations of conventional photoresists.

Implementation Method 1

a photosensitive agent (a photoacid generator) for generating an acid through excimer laser irradiation

Methodology Applied

Scientific EffectPhotoexcitation: Photoelectric Effect

Implementation Method 2

KrF laser (243 nm) photoresist for photo microprocessing

Methodology Applied

Scientific EffectLaser emission: Laser

Implementation Method 3

an organic solvent is used as the developing solution for removing the unexposed portion

Methodology Applied

Scientific EffectDifferential solubility: Solvation

Data Source

PatentUS10162261B2Negative photoresist composition for KrF laser for forming semiconductor patterns

Publication Date: 2018.12.25 YOUNG CHANG CHEMICAL CO LTD

AI summary

Provided is a negative photoresist composition for a KrF laser for semiconductor pattern formation, which includes a predetermined compound in order to improve the properties of a conventional negative photoresist, thereby realizing high transparency, high resolution and an excellent profile, even in the presence of an exposure source having a short wavelength compared to the conventional negative photoresist, and is thus suitable for use in semiconductor processing.