Silicon Nitride Barrier for Plastic Substrate Adhesion

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Solution Overview

Problem

The production of reliable electronic devices with organic layers is hindered by degradation due to moisture and oxygen contamination, and ensuring sufficient adhesion between inorganic metal and organic layers is challenging.

Innovation Solution

A method involving a silicon nitride layer as a planarising layer over a plastic substrate, which serves to improve adhesion and act as a barrier against moisture and oxygen ingress, using sputter coating and plasma treatment to achieve high purity and low water vapour transmission rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plastic substrate is used to support electronic elements, then flexibility and ease of manufacture are improved, but reliability deteriorates due to degradation from moisture and oxygen ingress

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A nitride layer is introduced as an intermediary barrier between the plastic substrate and the electronic elements. This layer specifically blocks moisture and oxygen ingress while maintaining the flexibility and ease of manufacture of the plastic substrate, thereby resolving the contradiction between ease of manufacture and reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure combining plastic substrate with a nitride barrier layer. This composite material system leverages the flexibility and ease of manufacture of plastic while adding the moisture and oxygen blocking properties of nitride, thus improving reliability without sacrificing the advantages of plastic substrates

Inventive Principle:
Principle #40Composite materials

2Reliability

If an inorganic metal layer is used for conductive elements, then electrical conductivity is improved, but adhesion to organic layers deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidadhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The nitride layer serves as a mediator between the inorganic metal conductive elements and the organic planarisation layer. It provides a surface that enhances adhesion for the metal layer while maintaining the electrical conductivity benefits of inorganic materials, thus resolving the adhesion contradiction

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 silicon nitride layer enhances adhesion between metal and organic layers, effectively preventing moisture and oxygen ingress, thereby increasing the reliability and stability of electronic devices.

Implementation Method 1

the nitride layer has a smaller water vapour transmission rate than any layer between the carrier and the device substrate

Methodology Applied
Scientific EffectBarrier property:

Implementation Method 2

there can be the problem of ensuring sufficient adhesion between an inorganic metal layer and an underlying organic layer, such as an organic planarisation layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

using sputter coating and plasma treatment to achieve high purity and low water vapour transmission rates

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 4

using sputter coating and plasma treatment to achieve high purity and low water vapour transmission rates

Methodology Applied
Scientific EffectPlasma: Plasma

Data Source

PatentEP2433320B1Method of manufacturing electronic devices
Publication Date: 2020.04.22 FLEXENABLE LTD
  • EP2433320B1 patent drawingFigure 1

AI summary

Forming, between a supporting substrate and the bottom conductive layer of a stack of layers a plurality of electronically functional elements, a non-conducting layer that functions to increase the adhesion of said bottom conductive layer to the supporting substrate.