Display Gate Line Stack for Hillock and Diffusion Control
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Solution Overview
Problem
Existing display devices face issues such as hillock formation, diffusion at interfaces, and particle generation during manufacturing, which degrade performance and reliability.
Innovation Solution
A display device structure comprising a gate line with layers of aluminum or aluminum alloy, N-rich titanium nitride (TiNx), and Ti-rich metallic titanium nitride (metallic TiNx), along with a manufacturing method that deposits these layers using a Ti target while supplying N2, to prevent hillock formation, diffusion, and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer aluminum wire structure is used, then the manufacturing process is simple, but hillock formation occurs and reliability deteriorates
Solution Approach 1:
The patent applies composite materials by creating a multi-layer wire structure consisting of aluminum, titanium nitride (TiNx), and metallic titanium nitride layers. This composite structure prevents hillock formation while maintaining electrical conductivity, thereby improving reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The patent segments the single aluminum layer into multiple functional layers: an aluminum base layer for conductivity, a TiNx intermediate layer to prevent diffusion and hillock formation, and a metallic TiNx top layer for protection. This segmentation allows each layer to perform its specific function, improving overall wire reliability.
2Reliability
If titanium is used to cap aluminum wire, then hillock formation is prevented, but diffusion occurs at the interface and cleaning processes are required
Solution Approach 1:
The patent introduces titanium nitride (TiNx) as an intermediary layer between aluminum and metallic titanium nitride. This intermediate layer prevents direct contact between aluminum and titanium, thereby preventing diffusion at the interface while still maintaining hillock prevention capabilities. The TiNx layer acts as a barrier that eliminates the need for cleaning processes.
3Ease of manufacture
If conventional wire structures are used, then manufacturing is straightforward, but particle generation occurs during the manufacturing process
Solution Approach 1:
The patent uses a composite multi-layer structure where each layer is deposited in a controlled manner. The specific composition of aluminum, TiNx, and metallic TiNx layers reduces particle generation during the sputtering process, as the nitrogen-containing layers suppress particle formation compared to pure metal layers.
4Ease of manufacture
If the N/Ti molar ratio in metallic titanium nitride is not optimized, then deposition is easier, but resistance increases and performance deteriorates
Solution Approach 1:
The patent optimizes the N/Ti molar ratio in the metallic titanium nitride layer to a specific range (0.7 < N/Ti < 1.3). This parameter optimization ensures that the layer has both low resistance and good hillock prevention capabilities. By controlling this ratio, the patent achieves a balance between ease of deposition and electrical performance.
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 proposed solution effectively prevents hillock formation, reduces resistance, and minimizes particle generation, thereby enhancing the reliability and performance of display devices.
Implementation Method 1
forming a second layer including TiNx on the first layer by using a Ti target while supplying N2 into a chamber; and forming a third layer including a metallic TiNx on the second layer by using a Ti target while supplying N2 into the chamber
Data Source
AI summary
Provided is a display device. The display device includes: a substrate; a gate line disposed on the substrate; a transistor including a part of the gate line; and a light-emitting element connected to the transistor, in which the gate line includes a first layer including aluminum or an aluminum alloy, a second layer including titanium nitride, and a third layer including metallic titanium nitride. An N/Ti molar ratio of the metallic titanium nitride may be in a range from about 0.2 to about 0.75.