Micro LED RDL Metal Seal Ring for Moisture Barrier Encapsulation
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Solution Overview
Problem
Conventional display panels with pixel driver chips and micro LEDs are susceptible to moisture ingress, leading to corrosion of metal wiring layers and potential device failure due to the high organic content in redistribution layers (RDLs), which are not adequately protected by existing sealing structures.
Innovation Solution
Integration of a metal seal ring and inorganic barrier layers within the RDL to form a sealed box structure, combined with a panel crack/corrosion detector (PCD) to prevent moisture ingress and detect structural integrity, using fabrication methods like 'LED first' or 'LED last' sequences and thin film techniques for RDL formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing structures are used, then device simplicity is maintained, but moisture ingress occurs leading to corrosion of metal wiring layers
Solution Approach 1:
The patent employs a composite sealing structure consisting of multiple inorganic barrier layers (such as aluminum oxide, silicon nitride, or silicon oxide) combined with organic encapsulation layers. This multi-layer composite approach provides superior moisture and oxygen barrier properties compared to single-material sealing structures, effectively protecting the metal wiring layers from corrosion while maintaining structural integrity.
Solution Approach 2:
The sealing structure is divided into multiple discrete inorganic barrier layers and organic encapsulation layers stacked in sequence. Each layer serves a specific protective function, with inorganic layers providing moisture barrier properties and organic layers providing mechanical protection and stress relief. This segmented approach enhances overall protection effectiveness while allowing optimization of each individual layer.
2Reliability
If inorganic barrier layers are added to the RDL, then corrosion protection is improved, but manufacturing complexity increases
Solution Approach 1:
The inorganic barrier layers are formed on the metal wiring layers of the RDL before the organic encapsulation layers are applied. This preliminary formation of protective inorganic barriers ensures that the metal layers are protected from moisture and corrosion from the outset of the encapsulation process, preventing degradation before it can occur.
Solution Approach 2:
The patent utilizes thin-film deposition techniques to create inorganic barrier layers with controlled thickness and material composition. By adjusting deposition parameters such as layer thickness, material composition (aluminum oxide, silicon nitride, silicon oxide), and deposition conditions, the protective performance is optimized while maintaining compatibility with existing manufacturing processes.
3Strength
If metal seal ring is integrated into RDL, then mechanical integrity is enhanced, but device complexity increases
Solution Approach 1:
The metal seal ring integrated into the RDL structure serves multiple functions simultaneously: it provides mechanical reinforcement to enhance the structural integrity of the display panel, acts as an electrical connection element for signal routing, and contributes to the overall sealing structure when combined with inorganic barrier layers. This multi-functionality reduces the need for separate components.
Solution Approach 2:
The metal seal ring is merged with the RDL structure, combining the sealing function, mechanical support function, and electrical connection function into a single integrated component. This merging eliminates the need for separate sealing structures and support elements, simplifying the overall device architecture while maintaining enhanced mechanical integrity.
Data Source
AI summary
An electronic device and methods of fabrication are disclosed. In an embodiment, an electronic device includes a display panel including a display area, a peripheral edge surrounding the display area, and a border region along the peripheral edge and surrounding the display area. The display panel may further include an array of pixel driver chips, a redistribution layer (RDL) over the array of pixel driver chips, and an array of light-emitting diodes (LEDs) mounted on the RDL within the display area, where the RDL includes a metal seal ring in the border region.