Laminated Metal Electrode Undercutting Prevention in Array Substrates
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Solution Overview
Problem
The undercutting of laminated metal electrodes in display panel manufacturing leads to defects such as short circuits and packaging failures due to the dissolution of aluminum layers during the manufacturing process.
Innovation Solution
A method of forming a laminated metal layer with a titanium-first, aluminum-middle, and titanium-third configuration, where the third titanium layer is etched twice to ensure it is narrower than the aluminum layer, preventing undercutting and residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum layer is used as metal trace to avoid voltage drop, then electrical conductivity is improved, but resistance to acid and alkali chemicals deteriorates
Solution Approach 1:
The patent uses a laminated metal structure comprising multiple layers (titanium, aluminum, and titanium again) to combine the advantages of different materials. The aluminum layer provides low resistivity for good electrical conductivity, while the titanium layers provide chemical stability and resistance to etching, thus resolving the contradiction between conductivity and chemical resistance
Solution Approach 2:
The titanium layers act as protective intermediary layers that shield the aluminum layer from direct exposure to acid and alkali chemicals during manufacturing processes. This mediator approach allows the aluminum to maintain its electrical conductivity function without suffering from its poor chemical resistance
2Stability of the object's composition
If titanium layers are disposed on upper and lower layers of aluminum to form sandwich structure, then chemical stability is improved, but side-etching of exposed aluminum causes undercutting
Solution Approach 1:
The patent applies different widths to different layers of the laminated metal structure. The third metal layer (titanium) is designed with a width less than or equal to the second metal layer (aluminum), creating local structural variation that prevents uniform etching and avoids undercutting while maintaining chemical stability
Solution Approach 2:
The patent performs a preliminary etching process on the third metal layer before final patterning to pre-establish the width relationship between layers. This preliminary action prevents undercutting by ensuring the protective titanium layer extends sufficiently beyond the aluminum layer edges before any etching occurs
3Manufacturing precision
If third metal layer width is less than or equal to second metal layer width, then undercutting is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary etching of the third metal layer before final photoresist patterning to pre-establish the correct width relationship. This preliminary action simplifies the overall manufacturing process by preventing undercutting issues from arising later, rather than requiring complex real-time control mechanisms
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 configuration prevents undercutting and short circuits, ensuring stable metal electrodes and avoiding organic photoresist residue issues, thus enhancing display panel reliability and preventing packaging failures.
Implementation Method 1
there are still many process factors that cause exposed aluminum on the side of the laminated metal to be dissolved and etched
Implementation Method 2
performing a photolithography process on the first metal layer, the second metal layer, and the third metal layer
Implementation Method 3
since the titanium layer disposed on and under the aluminum layer 2′ has relatively stable chemical properties, the top layer of titanium 3 and the bottom layer of titanium 1 are not be side-etched
Data Source
AI summary
An array substrate, a method of manufacturing thereof, and a display panel are provided. A source-drain layers are formed by a laminated metal layer. The laminated metal layer includes a first metal layer, a second metal layer, and a third metal layer that are stacked in order. By etching the stacked metal layer twice, a width of the third metal layer in the formed source-drain layer is less than or equal to a width of the second metal layer, thereby solving the problem of the undercutting of the laminated metal electrode in the array substrate of the prior art.