Micro LED Mesa Structure for Higher Mass Transfer Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional micro light-emitting diodes (mLEDs) face challenges in mass transfer yield due to the breaking of sacrificial layers and diffusion of bonding material, which affects the reliability and efficiency of the manufacturing process.
Innovation Solution
The design includes a semiconductor epitaxial structure with a connecting wall forming an included angle of 105° to 165°, an insulation layer covering the connecting wall, and bonding electrodes that extend onto the second mesa surface, preventing sacrificial layer breakage and ensuring proper bonding without material diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connecting wall is formed with a steep angle (close to 90°) to reduce manufacturing complexity, then the manufacturing process is simpler, but the sacrificial layer is likely to break during bonding
Solution Approach 1:
The patent changes the geometric parameter of the connecting wall angle from close to 90° to within the range of 105° to 165°. This parameter modification reduces the stress concentration on the sacrificial layer during bonding, preventing breakage while maintaining manufacturing feasibility through controlled angle specification.
2Manufacturing precision
If the sacrificial layer is made thin to improve resolution, then the structural precision is higher, but the bonding material diffuses into the sacrificial layer causing abnormal transfer
Solution Approach 1:
The patent introduces an insulation layer as an intermediary barrier between the bonding material and the sacrificial layer. This intermediate structure prevents direct contact and diffusion of bonding material into the sacrificial layer, while still allowing the thin sacrificial layer to maintain its high resolution function.
Solution Approach 2:
The patent creates a composite structure combining the sacrificial layer and insulation layer working together. The insulation layer material is specifically selected to be compatible with both the sacrificial layer and bonding material, creating a multi-material system that prevents harmful diffusion while maintaining the precision benefits of the thin sacrificial layer.
3Reliability
If the first mesa surface and second mesa surface have large height difference to accommodate electrode connections, then the electrical connection is improved, but the sacrificial layer covering becomes unstable
Solution Approach 1:
The patent modifies the geometric parameters including the height difference between mesa surfaces and the connecting wall angle. By optimizing these parameters within specific ranges, the design achieves both adequate electrode connection capability and sacrificial layer stability, preventing breakage during bonding while maintaining electrical functionality.
Data Source
AI summary
A micro light-emitting device includes a micro light-emitting diode, a base frame, and a bridging structure. The micro light-emitting diode includes a semiconductor epitaxial structure including a first semiconductor layer, a second semiconductor layer, an active layer, a first mesa surface, a second mesa surface, and a connecting wall, a first contact electrode, a second contact electrode, a first bonding electrode, and a second bonding electrode. The connecting wall cooperates with the first mesa surface to form a first included angle that ranges from 105° to 165°. A micro light-emitting diode and a method of manufacturing a micro light-emitting device are also provided.