LED Passivation Opening Structure to Prevent Electrode Disconnection
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Solution Overview
Problem
Display devices, particularly those using light-emitting diodes (LEDs), suffer from disconnection defects in their electrodes, leading to pixel defects and reduced luminous efficiency.
Innovation Solution
A light-emitting element design featuring a passivation layer that exposes specific portions of the electrodes, minimizing electrode disconnection by reducing the height of the passivation layer around the electrodes and preventing damage during manufacturing, thereby reducing pixel defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the passivation layer completely covers the first electrode, then the electrode is protected from damage during manufacturing, but the electrode may become disconnected due to stress or manufacturing defects
Solution Approach 1:
The passivation layer is segmented into different regions: a first passivation layer that covers part of the first electrode and a second passivation layer that covers the remaining part. This segmentation allows the electrode to be exposed in certain areas, preventing complete disconnection while maintaining protection in other areas.
Solution Approach 2:
Different portions of the passivation layer have different coverage characteristics. The first passivation layer provides complete coverage for protection, while the second passivation layer provides partial coverage, exposing specific regions of the first electrode. This local variation in passivation quality prevents electrode disconnection by maintaining exposure in critical areas while protecting other areas.
2Reliability
If the passivation layer height is reduced around the electrodes, then electrode exposure is improved and disconnection is minimized, but the protective coverage is reduced
Solution Approach 1:
The passivation structure is divided into multiple segments with different heights and coverage areas. The first passivation layer maintains full coverage for protection, while the second passivation layer is positioned to expose specific electrode portions, achieving both protection and disconnection prevention simultaneously.
Solution Approach 2:
The solution moves from a single-layer passivation approach to a multi-layer passivation structure with different spatial configurations. By adding the second passivation layer at a different position and with different coverage, the system achieves both electrode exposure and protection without compromising either function.
3Ease of manufacture
If the passivation layer completely covers all semiconductor layers and electrodes, then manufacturing simplicity is maintained, but electrode disconnection defects occur
Solution Approach 1:
The passivation process is segmented into multiple stages with different coverage requirements. The first passivation layer is formed to cover the electrode, and the second passivation layer is formed subsequently to expose specific portions. This segmented approach maintains manufacturing simplicity while preventing electrode disconnection.
Solution Approach 2:
The first passivation layer is formed in advance to provide base coverage and protection. Then the second passivation layer is added to create the exposure pattern. This preliminary action of forming the first layer simplifies the overall process by establishing a foundation before adding the exposure-specific second layer.
Data Source
AI summary
A light-emitting element and display device including the same are disclosed. A light-emitting element includes a first semiconductor layer, first electrodes disposed on one side and the other side of the first semiconductor layer, a light-emitting layer on the first semiconductor layer and between the first electrodes, a second semiconductor layer on the light-emitting layer, a second electrode on the second semiconductor layer, and a passivation layer covering at least a part of the first semiconductor layer, at least a part of the light-emitting layer, and at least a part of the second semiconductor layer, in which first opening portions, which expose a part of a top surface and a part of a side surface of each of the first electrodes, are on the passivation layer. Therefore, a height of a top surface of the passivation layer around the first electrode of the light-emitting element is reduced.