Display Panel Composite Metal Layer for Cu Barrier Corrosion Control
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Solution Overview
Problem
The Cu/Mo stack structure in thin film transistors experiences a strong galvanic corrosion effect due to a large corrosion potential difference, leading to a hollow structure formation at the interface, resulting in defective wires or a black screen in display panels.
Innovation Solution
A composite metal layer with a magnesium-aluminum alloy barrier layer and a copper main body layer, where the corrosion potential difference between the layers is controlled between −0.1V and 0.3V to reduce the etching rate and prevent hollowing out, thereby improving the display panel's yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a Cu/Mo stack structure is used in thin film transistors, then the metal film structure can be formed, but a strong galvanic corrosion effect occurs due to large corrosion potential difference, causing hollow structure formation at the interface
Solution Approach 1:
The patent changes the material composition of the barrier layer from pure Mo to a Mo-based alloy containing at least one of Nb, Ta, or W. This material parameter change adjusts the corrosion potential of the barrier layer, reducing the galvanic corrosion potential difference with the Cu layer to 0.5-1.5V, thereby suppressing the galvanic corrosion effect and preventing hollow structure formation at the interface.
Solution Approach 2:
The patent employs a composite metal film structure where the barrier layer is composed of Mo combined with Nb, Ta, or W elements. This composite material approach creates a multi-element alloy structure that optimizes both the corrosion resistance and electrical properties, reducing galvanic corrosion while maintaining the necessary functional performance of the metal stack.
2Ease of manufacture
If etching process is applied to Cu/Mo stack structure, then the metal pattern can be formed, but the etching rate of Mo accelerates due to galvanic corrosion, forming hollow structures at the interface
Solution Approach 1:
By changing the barrier layer material from pure Mo to a Mo-based alloy with Nb, Ta, or W, the patent modifies the electrochemical parameters of the structure. This reduces the galvanic corrosion potential difference during etching, thereby controlling the etching rate more uniformly and preventing the formation of hollow structures at the Cu/Mo interface, improving manufacturing precision.
3Quantity of substance
If tiny gap is formed at Cu/Mo interface, then hollow structure is created, but this causes defective wires or black screen during lighting test
Solution Approach 1:
The patent uses a composite Mo-based alloy barrier layer that enhances the structural integrity and adhesion between the Cu and barrier layers. This composite structure prevents gap formation at the interface, ensuring continuous metal film and eliminating the harmful effects of hollow structures such as defective wires and black screens.
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 controlled corrosion potential difference reduces the etching rate and gap between the layers, preventing defective lines and black screens, and enhancing the display panel's production yield by alleviating the hollowing out issue.
Implementation Method 1
due to a corrosion potential difference between Cu and Mo being large, a strong galvanic corrosion effect causes an etching rate of Mo to accelerate
Data Source
AI summary
A display panel and an electronic device are provided. The display panel includes a substrate and a composite metal layer, and the composite metal layer includes a barrier layer and a main body layer. By reducing the potential difference between the main layer and the barrier layer, a gap between the main layer and the barrier layer can be reduced. In this way, the problem of hollowing out the barrier layer in the composite metal layer is alleviated, the problem of defective lines or black screen of the display panel is prevented, and the yield of the display panel is improved.