OLED Partition Structure for Selective Etching and Electrode Contact
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Solution Overview
Problem
The manufacturing of OLED display devices faces challenges in improving reliability due to issues with the etching process, particularly with the use of mixed acids containing phosphoric acid, nitric acid, and acetic acid, which can lead to conduction failures if the bottom layer is eroded excessively.
Innovation Solution
A display device configuration with a partition structure that includes a conductive bottom layer and a stem layer, where the bottom layer has a smaller etching rate than the stem layer, and the upper portion is formed of materials with lower etching rates, ensuring proper contact and conduction between electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mixed acid etching is used to remove the stem layer, then the stem layer can be effectively removed, but the bottom layer may be damaged due to its similar etching resistance
Solution Approach 1:
The partition structure is designed with different materials for different parts: the stem layer uses aluminum or aluminum alloy which is highly etchable by mixed acid, while the bottom layer uses titanium or titanium nitride which has resistance to mixed acid etching. This local differentiation of material properties enables selective etching of the stem layer while preserving the bottom layer, resolving the contradiction between etching precision and electrode integrity
Solution Approach 2:
The invention changes the material composition parameters of the partition layers, specifically selecting materials with vastly different etching rates to the mixed acid solution. The stem layer is made of aluminum-based materials with high etching rate, while the bottom layer uses titanium-based materials with low etching rate, enabling differential etching that achieves both precise stem removal and bottom layer protection
2Reliability
If the partition structure is made entirely of conductive material, then conductivity is maintained, but etching selectivity between layers is reduced
Solution Approach 1:
The partition is designed as a multi-layer structure where only specific layers (stem layer and upper portion) are made conductive using aluminum or aluminum alloy, while the bottom layer uses non-conductive or less conductive titanium or titanium nitride. This local differentiation maintains necessary conductivity in critical areas while enabling etching selectivity through material property differences
Solution Approach 2:
The partition structure employs composite material design with at least two different materials: aluminum or aluminum alloy for conductive and highly etchable portions, and titanium or titanium nitride for the bottom layer with etching resistance. This composite approach simultaneously achieves conduction reliability where needed and etching selectivity for manufacturing precision
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 configuration enhances the reliability of OLED display devices by preventing excessive erosion of the bottom layer during etching, ensuring stable conduction and maintaining the shape of the partition structure, thus improving the manufacturing process.
Implementation Method 1
the bottom layer is formed of a material which has a smaller etching rate to a mixed acid containing phosphoric acid, nitric acid, and acetic acid than the stem layer
Data Source
AI summary
According to one embodiment, a display device comprises a first lower electrode, a rib including a first pixel aperture, a partition including a lower portion on the rib and an upper portion protruding from a side surface of the lower portion, a first upper electrode, and a first organic layer between the first lower electrode and the first upper electrode. The lower portion includes a bottom layer and a stem layer on the bottom layer. The bottom layer is formed of a material which has a smaller etching rate to a mixed acid containing phosphoric acid, nitric acid, and acetic acid than the stem layer and which is conductive.