Back Gate Electrode Protection in Display Devices

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Solution Overview

Problem

Display devices face challenges in protecting electrode components during the etching process, leading to potential damage and external influences.

Innovation Solution

The display device incorporates a cover layer that acts as an etch stopper for the back gate electrode in the open area, formed from the same material as the semiconductor layer, and includes a passivation layer with openings, reducing external influences and preventing damage during etching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the passivation layer is etched to open the open area, then access to the back gate electrode is enabled, but the back gate electrode may be damaged by external influences during the etching process

Engineering Contradiction:

Improveaccess to back gate electrodeVSAvoiddamage to back gate electrode

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A cover layer is introduced as an intermediary protective structure between the etching environment and the back gate electrode. This cover layer is selectively removed in the open area to provide access to the back gate electrode, while remaining in other areas to protect the electrode from damage during etching processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The passivation layer is segmented by creating an open area where the cover layer is removed, allowing selective access to the back gate electrode. This segmentation enables the etching process to reach the back gate electrode in specific regions while maintaining protection in other regions.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the back gate electrode is exposed in the open area, then etching access is provided, but external influences may affect the electrode components

Engineering Contradiction:

Improveetching accessVSAvoidexternal influences on electrode

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The cover layer configuration is optimized with local quality variations - it is removed in the open area to provide etching access while being maintained in surrounding areas to protect against external influences. This local differentiation allows simultaneous achievement of etching accessibility and environmental protection.

Inventive Principle:

Principle #3Local quality

3Reliability

If a cover layer is added to protect the back gate electrode, then damage during etching is reduced, but device structure becomes more complex

Engineering Contradiction:

Improveprotection of back gate electrodeVSAvoidlayer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cover layer serves multiple functions simultaneously: it protects the back gate electrode from damage during etching processes, acts as a structural layer in the device architecture, and can be selectively removed to provide access where needed. This multi-functionality reduces the need for additional dedicated protective layers, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20220093679A1Display device

Publication Date: 2022.03.24 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display area, a non-display area, and an open area between the display area and the non-display area. The display device includes a substrate; a transistor on the substrate, a back gate electrode, wherein at least a portion of the back gate electrode overlaps the transistor and at least another portion of the back gate electrode overlaps the open area, a passivation layer on the transistor, and including an opening that overlaps the open area, and a cover layer overlapping the back gate electrode in the open area.