Tapered Conductive Pattern with Titanium Nitride Capping
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Solution Overview
Problem
In display devices, conductive patterns with low-resistance materials like aluminum face challenges due to material damage during manufacturing processes such as annealing and etching, leading to signal delays and reliability issues, especially in high-resolution displays.
Innovation Solution
A conductive pattern is formed with a capping layer made of multiple component layers, including titanium nitride, which prevents metal diffusion and surface damage during cleaning and etching processes, ensuring the reliability of low-resistance conductive patterns by controlling taper angles and using specific etching conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a low-resistance material like aluminum is used for signal wirings, then signal delay is reduced, but the material becomes susceptible to damage during manufacturing processes such as annealing and etching
Solution Approach 1:
A capping layer made of titanium nitride is introduced as an intermediary between the aluminum signal wiring and the manufacturing environment. This capping layer protects the aluminum from damage during annealing and etching processes while allowing the aluminum to maintain its low-resistance properties for signal transmission.
Solution Approach 2:
The conductive pattern is formed as a composite structure combining aluminum (for low resistance) with titanium nitride capping layers (for protection). This composite approach allows each material to fulfill its optimal function - aluminum provides low-resistance signal transmission while titanium nitride provides manufacturing process protection.
2Productivity
If a capping layer with large taper angle is used, then etching speed is improved, but insulating material cannot be properly filled in the vicinity of the side surface
Solution Approach 1:
The taper angle of the capping layer is optimized to a specific range (20° to 40°) that balances etching speed with insulating material filling capability. This parameter optimization ensures that the etching process proceeds efficiently while allowing insulating material to be properly deposited in the side surface region.
3Stability of the object's composition
If titanium is used as the first capping component layer, then diffusion prevention is achieved, but the material reacts with fluoric acid during cleaning processes
Solution Approach 1:
Titanium nitride is used as the first capping component layer directly contacting the aluminum, providing both diffusion prevention and chemical inertness to fluoric acid cleaning solutions. Titanium may be used in subsequent layers where diffusion prevention is less critical but other properties are needed.
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
The solution significantly reduces signal delay and improves display quality by maintaining low resistance and reliability of conductive patterns, even in high-resolution organic light emitting diode displays.
Implementation Method 1
the first capping component layer disposed on the main conductive layer and including titanium nitride, thereby preventing or mitigating the diffusion of the metal components at the interface with the main conductive layer
Implementation Method 2
since titanium nitride does not easily react with fluoric acid or the like compared to titanium, the surface of the main conductive layer may be protected during a cleaning process
Data Source
AI summary
A conductive pattern for a display device includes a first layer including aluminum or an aluminum alloy disposed on a substrate and forming a first taper angle with the substrate, and a second layer disposed on the first layer forming a second taper angle with the first layer, in which the second taper angle is smaller than the first taper angle.