Resist Underlayer Composition Using Propylene Glycol Monomethyl Ether

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Solution Overview

Problem

The challenge in the semiconductor lithography process is to find a resist underlayer film-forming composition with excellent solubility in a solvent that is safe for human use, as conventional organic solvents like N-methyl-2-pyrrolidone and cyclohexanone are harmful and have limited availability, making it difficult to form a homogeneous film.

Innovation Solution

A resist underlayer film-forming composition comprising a polymer with specific structural units and a solvent containing more than 50% propylene glycol monomethyl ether, which ensures high solubility and safety, along with optional crosslinkable compounds and surfactants to enhance film formation and properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic solvents (N-methyl-2-pyrrolidone, cyclohexanone) are used, then good solubility and film formation are achieved, but harmfulness to human body increases and safety decreases

Engineering Contradiction:

Improvefilm formation qualityVSAvoidharmfulness to human body

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the solvent system by using propylene glycol monomethyl ether as the main solvent component (50-100 mass%), replacing conventional harmful solvents. This parameter change maintains film formation quality while eliminating the harmful effects of N-methyl-2-pyrrolidone and cyclohexanone.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adopts propylene glycol monomethyl ether, a safer and more environmentally friendly solvent, replacing the harmful conventional solvents. This substitution maintains the functional requirements for film formation while using a safer, more disposable-like chemical system that degrades more safely in the environment.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If propylene glycol monomethyl ether is used as the main solvent, then safety and low harmfulness are improved, but solubility of conventional polymers decreases making homogeneous film formation difficult

Engineering Contradiction:

ImprovesafetyVSAvoidsolubility and homogeneous film formation

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the molecular structure parameters of the polymer by introducing specific structural units (Formulae 1a, 1b, 1c) containing aromatic rings and glycidyl ether groups. These structural modifications enable the polymer to be highly soluble in propylene glycol monomethyl ether, achieving homogeneous film formation while maintaining safety.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer structure combining multiple functional groups (aromatic rings from naphthalene or phenylene, glycidyl ether groups, and hydroxyl/carboxyl groups) to achieve both high solubility in propylene glycol monomethyl ether and the necessary film-forming properties. This composite molecular structure resolves the contradiction between safety and solubility.

Inventive Principle:

Principle #40Composite materials

3Reliability

If polymer structure is modified to increase solubility in propylene glycol monomethyl ether, then homogeneous film formation is achieved, but polymer synthesis complexity increases

Engineering Contradiction:

Improvehomogeneous film formationVSAvoidpolymer synthesis complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the polymer synthesis into modular steps using commercially available building blocks (glycidyl ether compounds with specific structures and aromatic compounds with hydroxyl/carboxyl groups). This segmentation simplifies the synthesis process compared to creating entirely new polymer structures, while still achieving the required solubility and homogeneous film formation.

Inventive Principle:

Principle #1Segmentation

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 allows for the formation of a homogeneous resist underlayer film with high solubility in propylene glycol monomethyl ether, ensuring low human harm and safety, while providing sufficient film resistance and application stability for semiconductor processing.

Implementation Method 1

a polymer having a structural unit of Formula (1a) or Formula (1c) and a structural unit of Formula (1b)... excellent solubility in a solvent containing propylene glycol monomethyl ether

Methodology Applied

Scientific EffectSolubility: Solvation

Data Source

PatentUS9534140B2Resist underlayer film-forming composition

Publication Date: 2017.01.03 NISSAN CHEM CORP

AI summary

There is provided a resist underlayer film-forming composition having excellent solubility in a solvent containing propylene glycol monomethyl ether as a main component. A resist underlayer film-forming composition comprising a polymer having a structural unit of Formula (1a) or Formula (1c) and a structural unit of Formula (1b) and a solvent containing more than 50% by mass of propylene glycol monomethyl ether, wherein in the polymer, the structural unit of Formula (1a) or Formula (1c) and the structural unit of Formula (1b) are arranged alternately.(In Formulae (1a) and (1b), Q is a phenylene group or a naphthylene group, m is 1 or 2, and each of n is independently 0 or 1).