Multilayer Conductive Pattern Etching Reliability
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Solution Overview
Problem
Existing display device manufacturing methods often result in damage to conductive patterns due to differing etching rates of layers, leading to reliability issues and potential tip formation, which can cause damage and reduce the effectiveness of the display device.
Innovation Solution
A method involving the sequential formation of conductive layers with specific etching rates, where the fourth layer is removed before forming a protective layer, ensuring that the second layer is not damaged during the etching process for forming pixel electrodes, and the conductive pattern is designed to prevent protrusion of the third layer from the second layer, thereby minimizing damage and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer conductive structure is formed with different materials, then the electrical conductivity and functionality are improved, but the etching rates of different layers vary causing damage to the conductive pattern
Solution Approach 1:
The conductive structure is divided into multiple layers (first conductive layer, second conductive layer, third conductive layer, fourth conductive layer) with different materials and functions. Each layer is segmented to perform specific roles: the second conductive layer provides high conductivity, while the third layer with slower etching rate protects underlying layers during etching processes. This segmentation allows differential etching rates to be managed systematically rather than causing uniform damage.
Solution Approach 2:
The third conductive layer is formed preliminarily on the second conductive layer before the final etching process. This preliminary layer acts as a protective barrier that prevents the etchant from directly attacking the second conductive layer with high etching rate. The fourth conductive layer is also formed preliminarily to control the etching profile and prevent tip formation during the etching process.
2Ease of manufacture
If the fourth conductive layer is removed after patterning, then the pixel electrode formation is enabled, but the second conductive layer becomes vulnerable to etchant damage
Solution Approach 1:
The protective layer is formed preliminarily on the conductive pattern before the pixel electrode formation process. This protective layer remains in place during the etching process used to form pixel electrodes, preventing the etchant from damaging the second conductive layer. The fourth conductive layer is removed after patterning to enable pixel electrode formation, but the protective layer continues to safeguard the underlying conductive structure throughout the process.
Solution Approach 2:
The protective layer serves as an intermediary element between the etchant and the second conductive layer. It allows the etching process to proceed for pixel electrode formation while simultaneously protecting the conductive pattern from damage. The protective layer mediates the interaction between the aggressive etchant and the sensitive conductive materials, enabling the process to continue without compromising structural integrity.
3Productivity
If the third layer etches faster than the second layer, then patterning is simplified, but tip formation occurs causing damage to the display device
Solution Approach 1:
The etching rate parameters of different conductive layers are specifically controlled and adjusted. The third conductive layer is designed with a slower etching rate than the second conductive layer, which is the opposite of the problematic condition. This parameter change prevents tip formation by ensuring that the protective third layer does not etch away faster than the conductive second layer, thereby eliminating the harmful geometric protrusions that would cause damage.
Solution Approach 2:
The differential etching rates between layers, which could potentially cause tip formation, are converted into a beneficial protective mechanism. The second conductive layer's higher etching rate is utilized to ensure it is completely patterned, while the third layer's slower etching rate naturally protects it from over-etching and tip formation. What could be a harmful discrepancy in etching rates is transformed into a protective feature that prevents damage.
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 approach prevents damage to the conductive pattern and improves the reliability of the display device by ensuring uniform etching and preventing tip formation, resulting in a more stable and efficient manufacturing process.
Implementation Method 1
the fourth layer of the conductive pattern may be removed by a wet etching process
Implementation Method 2
the fourth layer of the conductive pattern may be removed by a chemical mechanical polishing/planarization
Implementation Method 3
etching each of the first conductive layer, the second conductive layer, the third conductive layer, and the fourth conductive layer with an etchant using the photoresist pattern as an etching mask
Data Source
AI summary
A method of manufacturing a display device may include sequentially forming a first conductive layer, a second conductive layer including copper (Cu), a third conductive layer, and a fourth conductive layer on a substrate, patterning the first conductive layer, the second conductive layer, the third conductive layer, and the fourth conductive layer together to form a conductive pattern including a first layer, a second layer, a third layer, and a fourth layer sequentially on the substrate, removing the fourth layer of the conductive pattern, forming a protective layer covering at least a sidewall of the conductive layer on the substrate, and forming a display element on the protective layer.