Cross-linked Layer Formation for Directed Self-Assembly

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Solution Overview

Problem

Thermally crosslinkable polymer mats, such as X-PS, dewet during thermal crosslinking on popular hardmask materials like SOG, making directed self-assembly (DSA) techniques incompatible with many substrates used in modern microelectronic device manufacturing, hindering industry implementation.

Innovation Solution

A method involving partial photocrosslinking followed by thermal crosslinking of a photo- and thermally cross-linkable substance to form a cross-linked layer on substrates, including those prone to dewetting like SOG, without significantly altering the surface properties, using a tool compatible with standard semiconductor processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If thermal crosslinking is performed on hardmask materials like SOG, then the polymer mat can be crosslinked to form a guiding pattern, but the polymer mat dewets and breaks into droplets during heating

Engineering Contradiction:

Improvestability of polymer matVSAvoidcompatibility with hardmask materials

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies preliminary photocrosslinking to the polymer mat before thermal crosslinking. This preliminary action modifies the polymer structure in advance, creating a more stable network that prevents dewetting during subsequent thermal processing on hardmask substrates like SOG

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical parameters of the polymer by introducing photocrosslinkable groups (such as cinnamyl or vinyl groups) that undergo photo-induced polymerization. This parameter change enables the polymer to form a stable crosslinked network that maintains compatibility with hardmask materials during thermal processing

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If complete thermal crosslinking is performed, then the polymer mat achieves full crosslinking stability, but the surface properties are significantly altered which affects self-assembly

Engineering Contradiction:

Improvecrosslinking stabilityVSAvoidsurface property modification

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent employs partial photocrosslinking instead of complete crosslinking. This partial action provides sufficient stability to prevent dewetting while preserving enough surface property characteristics to enable subsequent self-assembly processes. The photocrosslinking is controlled to achieve the minimum necessary crosslink density without over-modifying the surface

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses photocrosslinking as an intermediary step between the polymer deposition and thermal crosslinking. This intermediary photochemical process creates a controlled crosslinked network that mediates between the need for stability and the need to preserve surface properties for self-assembly

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If conventional thermal crosslinking is used, then the process is simple and rapid, but it is incompatible with hardmask materials used in modern semiconductor manufacturing

Engineering Contradiction:

Improveprocessing speedVSAvoidsubstrate compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces photocrosslinking as an intermediary step that enables compatibility with hardmask materials while maintaining processing efficiency. This intermediate photochemical treatment prepares the polymer mat for subsequent thermal processing on substrates like SOG that would otherwise cause dewetting

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite crosslinked structure by combining photocrosslinked and thermally crosslinked networks. This composite material approach provides both the stability needed for hardmask compatibility and the processing characteristics required for rapid manufacturing

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

Enables the formation of a stable cross-linked layer for directing self-assembly on various substrates, including SOG, without dewetting, maintaining surface properties and allowing for rapid processing, thus overcoming the incompatibility issues with hardmask materials.

Implementation Method 1

photocrosslinking the cross-linkable substance partially

Methodology Applied

Scientific EffectPhotocrosslinking: Photopolymerisation

Implementation Method 2

cross-linking the substance further thermally

Methodology Applied

Scientific EffectThermal crosslinking:

Data Source

PatentUS10840090B2Method for forming a cross-linked layer

Publication Date: 2020.11.17 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)

AI summary

A method for forming on a substrate a cross-linked layer for directing the self-assembly of a self-assembling material is provided. The method including: (a) providing a structure having the substrate; (b) providing on the substrate a layer of a photo- and thermally cross-linkable substance which, when crosslinked, is suitable for directing the self-assembly of a self-assembling material; (d) photocrosslinking the cross-linkable substance partially; and (d) cross-linking the substance further thermally, thereby forming the cross-linked layer.