Photocrosslinkable Coating Composition for Stepped Substrates

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Solution Overview

Problem

Conventional photocrosslinking materials for resist underlayer films in semiconductor manufacturing suffer from insufficient filling properties and heat shrinkage due to degassing, leading to unfavorable flattening properties on stepped substrates.

Innovation Solution

A composition for coating stepped substrates comprising a reaction product of an epoxy group-containing compound and cinnamic acid, which undergoes photodimerization to form a cyclobutane ring, eliminating the need for crosslinkers and acid catalysts, thereby preventing viscosity increase and heat shrinkage, and ensuring excellent filling and flattening properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If thermal crosslinking is used to fill patterns, then filling properties improve, but viscosity increases and heat shrinkage occurs

Engineering Contradiction:

Improvefilling propertiesVSAvoidviscosity

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent changes the crosslinking mechanism from thermal to photo-initiated, altering the activation parameter from temperature to light wavelength. This allows crosslinking to occur at room temperature upon UV irradiation, avoiding viscosity increase and heat shrinkage while maintaining good filling properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal field with a photo field to initiate crosslinking. Instead of using heat to activate crosslinking (thermal field), UV light is used to activate the photocationic polymerization initiator, substituting thermal energy with optical energy to achieve crosslinking without heat-related side effects

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If acid catalysts and crosslinkers are used for photocrosslinking, then crosslinking efficiency improves, but complexity of composition increases

Engineering Contradiction:

Improvecrosslinking efficiencyVSAvoidcomposition complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the crosslinker and photocationic polymerization initiator into a single compound molecule. The compound contains both the crosslinkable functional groups (epoxy, oxetane, or cyclic carbonate groups) and the photocationic polymerization initiator functionality, eliminating the need for separate crosslinker and catalyst components

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The compound serves multiple functions simultaneously: it acts as both the crosslinking agent and the photocationic polymerization initiator. This multi-functional design simplifies the composition by eliminating the need for separate crosslinkers and acid catalysts, while maintaining effective crosslinking efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If conventional photocrosslinking materials are used, then crosslinking occurs, but degassing and heat shrinkage occur reducing flattening properties

Engineering Contradiction:

ImprovecrosslinkingVSAvoidflattening properties

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces thermal crosslinking with photo-initiated crosslinking. By using UV light to activate the photocationic polymerization initiator instead of heat, the process avoids thermal expansion and subsequent heat shrinkage, preventing degradation of flattening properties while achieving effective crosslinking

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the activation parameter from temperature to light wavelength. Crosslinking is initiated by UV irradiation at specific wavelengths (200-400 nm) rather than by heating, which eliminates thermal effects that cause degassing and heat shrinkage, thereby maintaining excellent flattening properties

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 filling and flattening properties without thermal crosslinking or degassing, forming a flat film with minimal bias between patterned and unpatterned areas, enhancing the precision of semiconductor device production.

Implementation Method 1

a compound (C) having in the molecule a partial structure of Formula (1) wherein the partial structure of Formula (1) represents a cinnamic acid derivative

Methodology Applied

Scientific EffectPhotodimerization: Photopolymerisation

Data Source

PatentUS11155684B2Photocrosslinkable group-containing composition for coating stepped substrate

Publication Date: 2021.10.26 NISSAN CHEM CORP

AI summary

There is provided a composition for coating a stepped substrate that has high filling properties of a pattern, and is capable of forming a coating film that does not cause degassing and heat shrinkage, and is used to form a coating film having flattening properties on the substrate. The composition for coating a stepped substrate includes a compound (C) having in the molecule a partial structure of Formula (1) (where R1 and R2 are each independently a hydrogen atom, a C1-10 alkyl group, or a C6-40 aryl group; five R3s are each independently a hydrogen atom, a hydroxy group, a C1-10 alkoxy group, a C1-10 alkyl group, a nitro group, or a halogen atom; and * is a bond site to the compound); and a solvent.