Random Copolymer Neutral Layer for Directed Self-Assembly

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Solution Overview

Problem

Current methods for forming a neutral layer in directed self-assembly pattern formation, such as using hydroxy terminated random copolymers or BCB-based crosslinkable random copolymers, are inefficient due to long process times and high costs, which hinder the formation of fine patterns with vertical orientation in semiconductor and LCD processes.

Innovation Solution

A random copolymer with specific structural units, including carbamate ester groups, is used to form a neutral layer that promotes directed self-assembly, reducing process time and costs by providing excellent chemical stability and allowing for the formation of vertically oriented lamellar structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydroxy terminated random copolymer is used to form neutral layer, then neutral layer formation is achieved, but process time is excessively long (about three days for heat treatment)

Engineering Contradiction:

Improveneutral layer formation qualityVSAvoidheat treatment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the chemical composition parameters of the random copolymer by incorporating specific structural units (Formulae 1-3) with controlled mole ratios. This compositional parameter change enables the neutral layer to achieve the required formation quality in significantly reduced heat treatment time compared to conventional hydroxy terminated random copolymers

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite random copolymer structure combining multiple structural units (Formulae 1-3) with specific functional groups. This composite material approach provides both the neutral layer formation capability and the accelerated processing speed, resolving the contradiction between quality and time

Inventive Principle:

Principle #40Composite materials

2Reliability

If BCB-based crosslinkable random copolymer is used to form neutral layer, then neutral layer formation is achieved, but process costs are high due to complicated synthesis process

Engineering Contradiction:

Improveneutral layer formation qualityVSAvoidsynthesis process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the synthesis approach by using a random copolymer with specific structural units (Formulae 1-3) that can be manufactured through more straightforward polymerization processes. This parameter change in composition enables neutral layer formation without requiring the complicated BCB-based crosslinking synthesis, thereby reducing process costs while maintaining formation quality

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If conventional photoresist pattern formation process is used, then pattern formation is achieved, but line width of 20 nm or less is difficult to implement

Engineering Contradiction:

Improveline width precisionVSAvoidpattern formation capability

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the pattern formation process into two stages: first forming a guide pattern using conventional photoresist, then using block copolymer self-assembly to create the final fine patterns. This segmentation enables achievement of 20 nm or less line width while maintaining overall process productivity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a neutral layer formed from the specific random copolymer as an intermediary between the substrate and the block copolymer. This intermediary neutral layer enables the block copolymer to self-assemble into vertically oriented lamellar structures, achieving the required fine pattern precision that cannot be obtained by conventional photoresist alone

Inventive Principle:

Principle #24Intermediary (Mediator)

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 random copolymer significantly reduces process time and costs while maintaining chemical stability, enabling the formation of high-quality, vertically oriented patterns with minimal thickness variation, even under short heat treatment conditions.

Implementation Method 1

a process of forming a directed self-assembly (DSA) pattern using self-aligning of a block copolymer (BCP)

Methodology Applied

Scientific EffectDirected self-assembly: Self-Assembly

Implementation Method 2

the coated thin film is heated to a glass transition temperature (Tg) of BCP or higher, thereby rearranging, self-aligning or self-orienting BCP

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 3

heated to a glass transition temperature (Tg) of BCP or higher, thereby rearranging, self-aligning or self-orienting BCP

Methodology Applied

Scientific EffectThermal rearrangement:

Data Source

PatentUS11643488B2Random copolymer, laminate, and method for forming pattern

Publication Date: 2023.05.09 SK INNOVATION CO LTD

AI summary

Provided are a random copolymer for forming a neutral layer promoting directed self-assembly pattern formation, a laminate for forming a pattern including the same, and a method for forming a high-quality pattern using the same.