Micro-LED Groove Electrode Layout for Bonding and Luminous Area
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Solution Overview
Problem
The production yield of micro-LEDs is hindered by challenges in achieving sufficient bonding strength and effective luminous area due to the limitations of metal electrode design on micron-scale chiplets.
Innovation Solution
The micro-LED design includes a groove on the back side with a first mesa and a second mesa, where the first metal electrode is entirely within the groove, and the second metal electrode is partially on a mesa, with optimized insulating layers and electrode holes to enhance bonding and luminous area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first metal electrode is extended to connect with the first-type semiconductor layer, then the electrical connection is improved, but the electrode may bridge onto the second mesa causing reduced bonding area and insufficient bonding strength
Solution Approach 1:
The patent divides the electrode structure into distinct segments: the first metal electrode is confined to the groove and does not bridge onto the second mesa, while the second metal electrode is provided on the second mesa. This segmentation prevents the first electrode from interfering with the bonding area of the second electrode, thus maintaining both electrical connection reliability and bonding strength.
Solution Approach 2:
The groove acts as an intermediary structure that isolates the first metal electrode from the second mesa. By introducing this intermediate feature, the patent prevents the harmful bridging effect while maintaining the necessary electrical connections, thus resolving the contradiction between electrical connection and bonding strength.
2Manufacturing precision
If the chip size is reduced to increase pixel density, then the resolution is improved, but the area of the first metal electrode is reduced resulting in insufficient bonding strength
Solution Approach 1:
The patent utilizes the vertical dimension by confining the first metal electrode within the groove structure. This allows the electrode to maintain adequate bonding area in the horizontal plane even when chip size is reduced, as the groove provides vertical isolation and the electrode can extend vertically within the groove boundaries without occupying excessive horizontal space.
3Ease of manufacture
If the groove is made as an unenclosed step to reduce process margin, then the manufacturing complexity is reduced, but the structural stability may be compromised
Solution Approach 1:
The patent applies local quality by making the groove an unenclosed step structure rather than a fully enclosed cavity. This localized modification reduces the process margin requirements and manufacturing complexity while maintaining sufficient structural stability through the remaining enclosed portions and the overall device architecture.
Data Source
AI summary
A micro light-emitting diode (micro-LED) and a display apparatus are provided. The micro-LED includes a semiconductor layer sequence, which has a back side and a front side. The semiconductor layer sequence includes: a first-type semiconductor layer, a second-type semiconductor layer, and an active layer therebetween. The back side is provided with a groove, the groove penetrates through the second-type semiconductor layer and the active layer, and the first-type semiconductor layer is exposed through the groove. The back side includes: a first mesa, a second mesa, and a groove sidewall. A first metal electrode and a second metal electrode are disposed on the back side. The first metal electrode and the second metal electrode are configured for bonding with an external power supply. The first metal electrode is entirely disposed within the groove, to prevent the first metal electrode from bridging onto the second mesa.