Copper Array Substrate Oxidation Prevention via Passivation Trench
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Solution Overview
Problem
The existing oxide TFT array substrate in a copper+oxide coplanar structure faces issues with copper metal layer oxidation due to exposure to oxygen-rich environments and adverse interactions with silicon nitride layers, leading to poor display performance.
Innovation Solution
The method involves forming a passivation layer with a silicon nitride layer as the lower layer and a silicon oxide layer as the upper layer, and creating a trench in the passivation layer with a width ratio that prevents the oxide trench pattern from contacting the silicon nitride layer, thereby protecting the copper metal layer from oxidation and improving display characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the oxide trench pattern is formed directly on the copper metal layer, then the manufacturing process is simplified, but the copper metal layer is completely exposed to oxygen enriched environment and oxidized
Solution Approach 1:
The passivation layer is formed on the copper metal layer before the oxide trench pattern is created. This preliminary protective action prevents copper oxidation by establishing a barrier layer (silicon nitride and silicon oxide) that isolates the copper from the oxygen-enriched environment during subsequent processing steps.
Solution Approach 2:
The passivation layer acts as an intermediary between the copper metal layer and the oxide trench pattern. Specifically, the silicon nitride and silicon oxide layers serve as mediator materials that prevent direct contact between copper and oxygen, while still allowing the oxide trench to be formed in the appropriate location.
2Adaptability or versatility
If the lower layer of PVX is SiOx and upper layer is SiNx, then the structure follows conventional design, but SiOx accelerates oxidation of copper metal layer
Solution Approach 1:
The conventional passivation layer structure is inverted: instead of SiOx as the lower layer and SiNx as the upper layer, the invention uses SiNx as the lower layer and SiOx as the upper layer. This inversion resolves the oxidation acceleration problem because SiNx does not accelerate copper oxidation like SiOx does, while still providing effective passivation.
3Reliability
If the lower layer of PVX is SiNx and upper layer is SiOx, then copper oxidation is reduced, but hydrogen in SiNx adversely affects oxide trench pattern causing large current phenomenon
Solution Approach 1:
The passivation layer structure is optimized with different materials at different locations: SiNx is placed at the lower layer where it contacts the copper metal layer to prevent oxidation, while SiOx is placed at the upper layer where it contacts the oxide trench pattern to avoid hydrogen-related adverse effects. This local differentiation of material properties resolves both problems simultaneously.
4Reliability
If copper is used to form source and drain electrodes, then wire resistance is reduced and conductive effect is improved, but copper metal layer is exposed to oxygen enriched environment and oxidized
Solution Approach 1:
The harmful factor (oxygen) is extracted or isolated from the environment surrounding the copper metal layer by introducing a passivation layer. This layer removes the oxygen-enriched environment that would otherwise cause copper oxidation, while allowing the copper to maintain its excellent electrical conductivity properties.
Solution Approach 2:
The passivation layer serves as an intermediary barrier between the copper metal layer and the oxygen-enriched environment. This mediator layer allows the copper to function with high conductivity while preventing direct interaction with oxygen that would cause oxidation and degradation.
Data Source
AI summary
Embodiments of the present invention disclose an array substrate, a method of manufacturing an array substrate and a display device, which belong to field of display technology. The method includes: forming a gate metal pattern and a gate insulating layer in turn on a base substrate; forming a source-drain metal pattern that is made of a preset metal on the base substrate, on which the gate insulating layer is formed, the source-drain metal pattern comprising a source electrode and a drain electrode and the preset metal including at least copper; forming a silicon nitride layer and a silicon oxide layer in turn on the base substrate, which compose a passivation layer; forming a trench in the passivation layer at a position corresponding to a gap between the source electrode and the drain electrode, wherein a width of the trench in the silicon oxide layer is smaller than a width of the trench in the silicon nitride layer and is larger than or equal to a distance of the gap between the source electrode and the drain electrode; forming an oxide trench pattern on the source-drain metal pattern, with is not in contact with the silicon nitride layer. The present invention solves problems of high-degree oxidation of copper metal layer and poorer display performance of an existing array substrate, and achieves advantages of reducing oxidation of copper metal layer and improving display performance of the array substrate for a display device.