Polyimide Film Laminated Substrate High-Temperature Peeling

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Solution Overview

Problem

The challenge lies in forming functional elements on polymer films, which are limited by the lack of heat-resistant bonding means between polymer films and inorganic substrates, leading to issues with peeling and stress-induced damage during high-temperature processing, especially when temperatures exceed the glass transition or melting points of polymer compounds.

Innovation Solution

A polymer film laminated substrate is created with a thin film, such as aluminum oxide or composite oxides, and a silane coupling agent layer on the inorganic substrate, allowing for stable peeling with low force and maintaining bonding strength even at high temperatures by forming an easily-peelable and easily-bondable region, reducing stress on the functional element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a polymer film is bonded to an inorganic substrate using conventional adhesives, then the bonding process is simple, but the bonding strength is insufficient at high temperatures (200-500°C)

Engineering Contradiction:
Improvebonding process simplicityVSAvoidbonding strength at high temperature
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

A silane coupling agent layer is introduced as an intermediary between the inorganic substrate and polymer film. This coupling agent forms a bridge that provides both chemical bonding to the inorganic substrate and compatibility with the polymer film, enabling strong bonding at high temperatures while maintaining process simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The bonding structure becomes a composite system consisting of inorganic substrate + silane coupling agent layer + polymer film. This composite approach combines the heat resistance of inorganic materials with the flexibility of polymers through the intermediate coupling layer, achieving both high-temperature strength and ease of manufacture

Inventive Principle:
Principle #40Composite materials

2Productivity

If a polymer film is peeled from an inorganic substrate after high-temperature processing, then the functional element can be transferred to the polymer film, but stress causes the functional element to break

Engineering Contradiction:
Improvefunctional element transfer capabilityVSAvoidfunctional element integrity during peeling
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The bonding strength parameter is made variable through the silane coupling agent system. By controlling the coupling agent composition and processing conditions, the bonding strength can be optimized to allow clean peeling at high temperatures while maintaining functional element integrity, enabling both transfer capability and reliability

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If a polymer film is used as a substrate for functional elements, then weight and thickness are reduced with higher flexibility, but heat-resistant bonding means are limited

Engineering Contradiction:
Improvesubstrate weight reductionVSAvoidheat-resistant bonding capability
Core Design Contradiction:
Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The silane coupling agent serves as a mediator that extends the adaptability of polymer film substrates to high-temperature applications. This intermediary layer enables heat-resistant bonding while preserving the inherent advantages of polymer films (light weight, thinness, flexibility), making the lightweight substrate suitable for high-temperature functional element fabrication

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 enables the production of highly accurate flexible electronic devices with improved yield and recyclability of the inorganic substrate, while maintaining the integrity of the functional elements by reducing tension and defects during peeling and high-temperature processing.

Implementation Method 1

a silane coupling agent layer continuously or discontinuously formed on the thin film

Methodology Applied
Scientific EffectChemical adhesion: Chemical Bonding

Implementation Method 2

allowing for stable peeling with low force and maintaining bonding strength even at high temperatures by forming an easily-peelable and easily-bondable region, reducing stress on the functional element

Methodology Applied
Scientific EffectStress reduction: Stress Relaxation

Data Source

PatentUS11267216B2Polymer film laminated substrate and method for producing flexible electronic device
Publication Date: 2022.03.08 TOYOBO CO LTD

AI summary

[Problem] To provide a polyimide film laminated substrate in which stable peeling with a constant low force from an inorganic substrate is enabled when a polyimide film is to be peeled from an inorganic substrate even after heat treatment at a temperature exceeding 500° C. is performed.[Solution] Silane coupling agent treatment is performed on an inorganic substrate on which a thin film of an aluminum oxide, a thin film of a composite oxide of aluminum and silicon, a thin film of molybdenum or tungsten, or an alloy thin film of molybdenum and tungsten is formed continuously or discontinuously on a part of at least one surface thereof, and a polyimide film layer is further laminated on the silane coupling agent layer. In the obtained laminate, the part where the aluminum oxide thin film layer is present functions as an easily-peelable layer, the part where no aluminum oxide thin film layer functions as an easily-bondable part. The bonding strength of the easily-peelable part does not change even after heat treatment at 500° C. or more, and the low value is stably maintained.