Cyclic Olefin Copolymer Release Layer for Flexible Substrate Transfer

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Solution Overview

Problem

Conventional release layer materials are unsuitable for use in TFT processes due to mismatch with flexible substrate materials and low thermal resistance, making it difficult to transfer flexible displays from glass substrates to plastic substrates without damage.

Innovation Solution

A release layer material composed of cyclic olefin copolymers (COC) is applied, which forms a double-layer substrate structure with varying adhesion forces, allowing for the separation of flexible substrates from glass carriers without peeling off, using a method where a release layer with lower adhesion is first formed on a smaller area and a release layer with higher adhesion is formed on a larger area, enabling easy separation by cutting along the ends of the lower adhesion layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional release layer materials are used, then the fabrication process can proceed, but the thermal resistance is low and adhesion mismatch occurs causing substrate damage during transfer

Engineering Contradiction:

Improvesubstrate integrity during transferVSAvoidthermal resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the thermal and adhesive parameters of the release layer by selecting COC materials with specific thermal properties (thermal resistance > 0.3 W/m·K) and controlled adhesion forces, enabling the layer to withstand TFT fabrication temperatures while providing appropriate adhesion for substrate transfer

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategy by combining COC release layer with flexible substrate materials (polyimide, PET, PEN) that have complementary properties, creating a multi-layer structure where each material contributes specific thermal and mechanical characteristics to solve the adhesion mismatch and thermal resistance problems

Inventive Principle:

Principle #40Composite materials

2Reliability

If a single-layer release structure is used, then fabrication is simple, but separation causes peeling and damage to the flexible substrate

Engineering Contradiction:

Improvesubstrate separation integrityVSAvoidrelease layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the release structure into multiple functional layers: a first release layer with lower adhesion force and a second release layer with higher adhesion force. This segmentation allows controlled separation where the first layer releases first, preventing peeling damage to the flexible substrate during transfer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different adhesion characteristics to different parts of the release system. The first release layer has lower adhesion force for easy initial separation, while the second release layer has higher adhesion force to maintain substrate integrity, creating local quality variations that solve the separation problem

Inventive Principle:

Principle #3Local quality

3Strength

If flexible substrate is directly coated on glass carrier, then adhesion is strong, but laser annealing and transfer become difficult

Engineering Contradiction:

Improveadhesion force between substrate and carrierVSAvoidsubstrate transfer process

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent introduces a release layer as an intermediary between the flexible substrate and glass carrier. This intermediary layer provides temporary adhesion during fabrication but allows easy separation through laser annealing or mechanical release, solving both the adhesion strength and transfer ease requirements

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

This approach allows for the successful separation of flexible substrates from glass carriers without damage, maintaining the integrity of the release layer and flexible substrate, and can be fabricated using existing semiconductor apparatuses, addressing the limitations of conventional release layer materials in TFT processes.

Implementation Method 1

the flexible substrate has a greater adhesion force than that of the release layer to the carrier

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8273439B2Release layer materials, substrate structures comprising the same and fabrication method thereof

Publication Date: 2012.09.25 IND TECH RES INST

AI summary

A release layer material of cyclic olefin copolymers (COC) applied in flexible electrical devices represented by Formula (I) or (II) is provided. The invention also provides a substrate structure including the release layer. The substrate structure includes a carrier, a release layer overlying the carrier with one or more blocks with a first area, wherein the release layer includes cyclic olefin copolymers (COC) represented by the disclosed Formula (I) or (II), and a flexible substrate overlying the release layer and the carrier with a second area, wherein the second area is larger than the first area and the flexible substrate has a greater adhesion force than that of the release layer to the carrier. The invention further provides a method for fabricating the substrate structure.In Formula (I) or (II), X is 30-70, X+Y is 100 and R is —H, —CH3 or —C2H5.