Multilayer Pad Metal Structure for Display Substrate Corrosion Resistance
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Solution Overview
Problem
In display apparatuses, the metal sublayer at the edge of a pad has weak corrosion resistance, leading to damage during electrode etching processes, which can result in short circuits and increased complexity and cost due to the need for a thick pixel defining layer to protect the edge, requiring thinning using a half-tone mask and etching processes.
Innovation Solution
A display substrate with a pad area featuring a multilayer metal structure comprising a first metal sublayer with weak corrosion resistance, a second metal sublayer with strong corrosion resistance, and a conductive material layer covering the side surface of the metal layer, allowing for simultaneous formation of the conductive material layer and display electrodes without additional process steps or increased cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick pixel defining layer is used to cover the pad edge, then corrosion resistance is improved, but manufacturing complexity and cost increase due to required thinning processes
Solution Approach 1:
The metal layer is segmented into multiple sublayers with different functions: the first metal sublayer provides electrical conductivity, while the second metal sublayer specifically provides corrosion resistance at the pad edge. This segmentation allows each sublayer to be optimized for its specific function without requiring the entire pixel defining layer to be thickened.
Solution Approach 2:
The second metal sublayer is selectively positioned at the pad edge where corrosion resistance is most needed, rather than uniformly thickening the entire pixel defining layer. This local quality approach provides enhanced corrosion protection exactly where the etching process poses the greatest risk, while maintaining manufacturing efficiency.
2Manufacturing precision
If the pixel defining layer is thinned to improve welding quality, then welding quality is improved, but the pad edge becomes vulnerable to corrosion and damage
Solution Approach 1:
The metal layer is divided into functional sublayers where the first metal sublayer ensures good welding quality through appropriate thickness and material properties, while the second metal sublayer provides corrosion protection at the edge. This allows the pixel defining layer to be thinned for welding quality without compromising pad edge integrity.
Solution Approach 2:
The second metal sublayer is strategically placed at the pad edge to provide localized corrosion resistance, allowing the overall pixel defining layer thickness to be reduced for better welding quality while maintaining edge protection where it is most critical.
3Reliability
If additional protection layers are added to prevent corrosion, then corrosion resistance is improved, but process complexity and cost increase
Solution Approach 1:
The corrosion protection function is merged with the existing metal layer structure by adding a second metal sublayer during the same deposition process, rather than adding a separate protection layer in a subsequent process step. This integration maintains process efficiency while providing enhanced corrosion resistance.
Solution Approach 2:
The metal layer is formed as a composite structure with two different metal sublayers, each contributing different properties: the first sublayer provides conductivity and the second sublayer provides corrosion resistance. This composite approach achieves enhanced protection without requiring additional process steps or materials.
Data Source
AI summary
This disclosure provides a display substrate, a production method thereof, and a display apparatus. The display substrate comprises: a display area; and a pad area outside the display area. The pad area comprises at least one pad. The pad comprises: a metal layer, which comprises a first metal sublayer and a second metal sublayer laminated on the first metal sublayer, wherein a corrosion resistance of the second metal sublayer is stronger than that of the first metal sublayer; and a conductive material layer, which covers a side surface of the metal layer.