Backplane Pad Electrode Side Protection Layer

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Solution Overview

Problem

The formation of pixel electrodes in display devices can cause galvanic reactions between silver and aluminum electrodes, leading to corrosion and short-circuits of the pad electrodes, which damages the backplane.

Innovation Solution

A method of manufacturing a backplane that includes forming a side protection layer on the sidewall of the pad electrode using a combination of materials from the insulation layer and etching gases, such as chlorine and fluorine, to prevent corrosion and short-circuits, while also using chemical mechanical polishing to ensure the side protection layer does not exceed the pad electrode's surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the pixel electrode layer is etched to form the pixel electrode, then the pixel electrode can be formed, but galvanic reaction occurs between the pixel electrode layer and pad electrode causing corrosion and short-circuits

Engineering Contradiction:

Improvepixel electrode formationVSAvoidpad electrode integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

An etch-stop layer is introduced as an intermediary between the pixel electrode layer and the pad electrode. This etch-stop layer prevents direct contact between the two electrode layers during the etching process, thereby eliminating the galvanic reaction pathway while still allowing the pixel electrode to be formed through the insulation layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulation layer is segmented into multiple layers with different etchability characteristics. By stacking insulation layers with varying resistance to etching, the patent creates a structured barrier system that controls the etching process and prevents harmful interactions between electrodes while maintaining manufacturing precision.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the pixel electrode layer is etched, then the pixel electrode can be formed, but the pad electrode may be damaged by exposure to etching materials

Engineering Contradiction:

Improvepixel electrode formationVSAvoidpad electrode exposure to etchant

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The etch-stop layer serves as a protective intermediary that blocks the etchant from reaching the pad electrode. This intermediary layer allows the etching process to proceed for pixel electrode formation while simultaneously protecting the pad electrode from exposure to harmful etching materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The etch-stop layer is formed in advance before the pixel electrode layer is etched. This preliminary protective action ensures that when the etching process occurs, the pad electrode is already protected, preventing damage before it can happen.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If standard reduction potentials of pixel electrode layer and pad electrode materials are greatly different, then galvanic reaction is more likely to occur, but this difference is necessary for electrode functionality

Engineering Contradiction:

Improveelectrode functionalityVSAvoidgalvanic reaction

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The etch-stop layer acts as a physical intermediary that separates the two electrode materials with different standard reduction potentials. This separation prevents the electrochemical pathway for galvanic reaction while allowing each electrode to maintain its functional material composition and properties.

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 side protection layer effectively prevents damage to the pad electrodes by covering their sidewalls and preventing exposure to materials that induce galvanic reactions, thereby maintaining the integrity of the backplane and preventing corrosion and short-circuits.

Implementation Method 1

etching the pad electrode layer and a portion of the insulation layer by the photoresist pattern as an etch-stop layer so as to simultaneously form a pad electrode and a side protection layer

Methodology Applied

Scientific EffectChemical Vapor Deposition: Chemical Vapour Deposition

Implementation Method 2

forming a photoresist pattern on the pad electrode layer in the pad region, etching the pad electrode layer and a portion of the insulation layer by the photoresist pattern as an etch-stop layer

Methodology Applied

Scientific EffectPhotolithography: Photography

Implementation Method 3

using chemical mechanical polishing to ensure the side protection layer does not exceed the pad electrode's surface

Methodology Applied

Scientific EffectChemical Mechanical Polishing:

Data Source

PatentUS11164932B2Backplane for display device and method of manufacturing the same

Publication Date: 2021.11.02 SAMSUNG DISPLAY CO LTD

AI summary

A method of manufacturing a backplane for a display device includes forming an insulation layer on a substrate, forming a pad electrode layer on the insulation layer, forming a photoresist pattern on the pad electrode layer in the pad region, etching the pad electrode layer and a portion of the insulation layer by the photoresist pattern as an etch-stop layer so as to simultaneously form a pad electrode and a side protection layer, the side protection layer covering a sidewall of the pad electrode, and stripping the photoresist pattern.