Textured Conductive Electrode for Semiconductor Light-Emitting Device Bonding
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Solution Overview
Problem
The existing semiconductor light-emitting devices face challenges in transferring them to a wiring substrate due to a weak shear force between the device and bonding materials, leading to defects and increased fabrication costs.
Innovation Solution
A semiconductor light-emitting device structure is developed with a conductive electrode featuring a texturing surface, including a concave-convex region and an insulating region covered by a passivation layer, which enhances the shear force and structural stability during transfer, and is electrically connected to the wiring electrode using solder with grooves corresponding to the protruding portions of the concave-convex region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional flat conductive electrode is used, then the device structure is simple, but the shear force between the semiconductor light-emitting device and bonding materials is weak
Solution Approach 1:
The conductive electrode surface is transformed from a flat plane to a concave-convex surface with curved features. The texturing process creates protruding portions and recessed portions that increase the surface area and mechanical interlocking capability, thereby enhancing the shear force between the electrode and bonding materials without adding complex multi-layer structures
2Reliability
If the conductive electrode surface is textured to enhance shear force, then the bonding force improves, but the manufacturing process becomes more complex
Solution Approach 1:
The texturing of the conductive electrode surface is performed during the electrode formation process itself, before the bonding step. By pre-forming the concave-convex structure on the electrode, the enhanced bonding capability is built-in advance, eliminating the need for additional texturing steps later and simplifying the overall manufacturing process
3Productivity
If a flat electrode interface is used, then the fabrication process is simple, but defects occur due to weak shear force
Solution Approach 1:
The concave-convex surface structure of the conductive electrode creates mechanical interlocking with the bonding materials, significantly reducing defect formation during and after the bonding process. The curved features of the textured surface prevent delamination and improve joint reliability, thereby increasing production yield
Data Source
AI summary
Discussed is a display apparatus including a substrate having a wiring electrode; and a semiconductor light-emitting device that emits light to an upper surface thereof, has a conductive electrode electrically connected to the wiring electrode on a lower surface thereof, and has at least a side surface of which is covered by a passivation layer, wherein the conductive electrode comprises: an insulating region further covered by the passivation layer, and a concave-convex region exposed by the passivation layer and electrically connected to the wiring electrode, a surface of the concave-convex portion being formed with concavity and convexity.