Repair Line Integration in Thin Film Transistor Array Substrates
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Solution Overview
Problem
In flat panel display devices, such as organic light-emitting display devices, short-circuits can occur between wires, leading to defects and a reduction in aperture ratio, which is not efficiently addressed by existing technologies without compromising the device's performance.
Innovation Solution
A thin film transistor array substrate design that includes a repair line aligned on the same layer as the active layer, using the same semiconductor material, which crosses other lines to efficiently repair short-circuits without requiring additional mask processes, thus maintaining the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a repair line is added to repair short-circuits between wires, then the reliability of the device is improved, but the aperture ratio is reduced
Solution Approach 1:
The repair line is disposed on the same layer as the active layer, utilizing the horizontal plane dimension rather than adding vertical layers. This allows the repair line to cross short-circuited wires without occupying additional vertical space that would reduce the aperture ratio, thus resolving the contradiction between improving reliability and maintaining display area.
Solution Approach 2:
The repair line is divided into multiple segments that can be selectively formed in different pixel regions. Each segment can independently repair short-circuits in specific areas, allowing the aperture ratio to be maintained in regions without defects while still providing repair capability where needed, thus balancing reliability improvement with aperture ratio preservation.
2Ease of repair
If additional mask processes are used to form repair lines, then the repair functionality is improved, but the manufacturing complexity increases
Solution Approach 1:
The repair line is formed simultaneously with the active layer in the same mask process, merging the formation of functional and repair elements into a single step. This eliminates the need for separate mask processes dedicated to repair lines, thus improving repair functionality without increasing manufacturing complexity.
Solution Approach 2:
The same mask process and material layer serve dual purposes: forming the active layer for transistor operation and forming the repair line for defect correction. This multi-functionality approach allows the repair infrastructure to be built into the existing manufacturing flow without requiring additional process steps.
3Ease of repair
If the repair line is formed on a separate layer, then the repair capability is improved, but the device structure becomes more complex
Solution Approach 1:
Instead of creating a separate vertical layer for the repair line, the invention utilizes the same horizontal layer (active layer layer) for both functional and repair purposes. This dimensional approach allows the repair line to be integrated into the existing layer structure without adding vertical complexity to the device stack.
Data Source
AI summary
A substrate includes an active layer, a gate electrode, source and drain electrodes, first and second insulating layers, a first line and a second line on a same layer as the gate electrode, the first line and the second line include a same material as the gate electrode and are aligned in a first direction, a third line crosses the first line, the third line is on a same layer as the source and drain electrodes, includes a same material as the source and drain electrodes, and is aligned in a second direction, a repair line on a same layer as the active layer, the repair line includes a same material as the active layer, a pixel electrode in the pixel region, and the pixel electrode is on a same layer as a lower electrode of the gate electrode and includes a same material as the lower electrode.