Organic TFT Substrate Bank Insulating Layer Design
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Solution Overview
Problem
The fabrication process of organic thin film transistor (TFT) substrates is complex and prone to damage due to moisture and chemical permeation, especially with separate mask processes for forming bank insulating and organic semiconductor layers, leading to complications and reduced picture quality in liquid crystal display devices.
Innovation Solution
A TFT substrate design featuring a gate line, data line, organic TFT with a double-layer source and drain electrode structure, and a passivation layer covered by a bank insulating layer, where the bank insulating layer is formed using a half-tone or slit mask photolithography process to create dot and line holes for organic semiconductor and passivation layer deposition, respectively, enhancing hydrophilicity and simplifying the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate mask processes are used for forming bank insulating layer and organic semiconductor layer, then positioning precision can be achieved, but fabrication process complexity increases
Solution Approach 1:
The patent merges the formation of bank insulating layer and organic semiconductor layer into a single mask process. The bank insulating layer is formed with a specific pattern that directly defines both the bank structure and the organic semiconductor layer position, eliminating the need for separate mask processes while maintaining positioning precision through the integrated pattern design
2Reliability
If passivation layer is formed within hole of bank insulating layer, then organic semiconductor layer is protected, but non-uniform thickness causes staining and reduces picture quality
Solution Approach 1:
The patent segments the bank insulating layer into multiple functional regions: a bank region for defining the hole structure and a pad region for receiving the passivation layer. This segmentation allows the passivation layer to be formed on a flat pad surface rather than within a confined hole, ensuring uniform thickness while maintaining protection of the organic semiconductor layer through the bank structure
3Manufacturing precision
If conventional bank insulating layer structure is used, then organic semiconductor layer positioning is achieved, but moisture and chemical liquids permeate boundary causing damage
Solution Approach 1:
The patent forms the bank insulating layer with an integrated bank region and pad region structure before forming the organic semiconductor layer. The bank region extends to create a protective barrier that prevents moisture and chemical liquids from reaching the boundary between the passivation layer and organic semiconductor layer, providing preliminary protection against harmful factors
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 design simplifies the fabrication process, reduces damage to the organic semiconductor layer by protecting it with a passivation layer, and improves picture quality by ensuring uniformity and integrity of the organic TFT substrate.
Implementation Method 1
the bank insulating layer is formed using a half-tone or slit mask photolithography process to create dot and line holes
Data Source
AI summary
An organic thin film transistor substrate includes a gate line formed on a substrate, a data line intersecting the gate line and defining a subpixel area, an organic thin film transistor including a gate electrode connected to the gate line, a source electrode connected to the data line, a drain electrode facing the source electrode, and an organic semiconductor layer forming a channel between the source and drain electrodes, a passivation layer parallel with the gate line, for covering the organic semiconductor layer and peripheral regions of the organic semiconductor layer, and a bank insulating layer for determining the position of the organic semiconductor layer and the passivation layer.