Micro-LED Extension Electrodes with Concave Solder Spots
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Solution Overview
Problem
The reduction in size of LED chip electrodes leads to a higher number of dead pixels in Micro-LED display panels due to reduced bonding force with the driving backboard, resulting in lower yield and increased solder invalidation.
Innovation Solution
The formation of first and second extension electrodes with concave spots for soldering, which increases the contact area and bonding strength when soldered to the driving backboard, reducing the likelihood of solder invalidation and improving panel yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the LED chip electrode size is reduced, then the display resolution is improved, but the bonding force with the driving backboard is reduced
Solution Approach 1:
The electrode structure is segmented into three parts: contact electrode (on LED chip), extension electrode (on driving backboard), and solder. The extension electrode acts as an independent segment that bridges the gap between the small contact electrode and the larger solder area, allowing the contact electrode to remain small for high resolution while providing sufficient bonding area through the extended structure.
Solution Approach 2:
The extension electrode extends in the planar dimension from the contact electrode towards the solder, creating a dimensional transition zone. This dimensional extension allows the bonding interface to span a larger area without increasing the vertical height or compromising the miniaturization of the contact electrode, thus maintaining high resolution while improving bonding strength.
2Manufacturing precision
If the LED chip electrode size is reduced, then the display resolution is improved, but the solder invalidation increases
Solution Approach 1:
The soldering structure is segmented into contact electrode, extension electrode, and solder components. The extension electrode serves as a dedicated bonding interface segment that is optimized for solder attachment, separating the functions of electrical contact (contact electrode) and mechanical bonding (extension electrode + solder). This segmentation ensures reliable solder joints even when the contact electrode is miniaturized for high resolution displays.
3Strength
If the contact area between electrode and driving backboard is increased, then the bonding strength is improved, but the device complexity increases
Solution Approach 1:
The extension electrode merges multiple functions into a single structure: it serves as an electrical conductor, a mechanical support, and a bonding interface for the solder. By combining these functions into one integrated component rather than using separate elements, the design achieves improved bonding strength without proportionally increasing device complexity.
Solution Approach 2:
The extension electrode is designed as a multi-functional element that performs electrical conduction, mechanical support, and solder bonding simultaneously. This universal design allows a single structure to fulfill multiple roles, improving bonding strength while avoiding the need for additional separate components that would increase complexity.
Data Source
AI summary
An LED chip provided by an embodiment includes a first semiconductor layer; an active layer and a second semiconductor layer located sequentially on the first semiconductor layer. A first contact electrode extends through the active layer and the second semiconductor layer and is electrically connected to the first semiconductor layer; a second contact electrode is located on the second semiconductor layer and is electrically connected to the second semiconductor layer; a first extension electrode is located on the first contact electrode and is electrically connected to the first contact electrode, the first extension electrode comprises a plurality of concave spots for soldering; and a second extension electrode is located on the second contact electrode, electrically connected to the second contact electrode and isolated from the first extension electrode, and the second extension electrode includes a plurality of concave spots for soldering.