Patterned LED Substrate Cutting Region Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light emitting diode (LED) manufacturing processes face poor epitaxial quality due to lattice mismatch between materials, leading to stress and threading dislocations at the interface, which affects device performance.
Innovation Solution
A patterned substrate with integrated patterned structures in the cutting region, which reduces stress and dislocations by controlling the surface roughness and aspect ratio, improving epitaxial quality on the device-disposed region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional flat substrate is used for LED manufacturing, then the manufacturing process is simple, but lattice mismatch between materials generates stress and threading dislocations at the interface, resulting in poor epitaxial quality
Solution Approach 1:
The substrate surface is divided into different regions with different roughness characteristics. The device-disposed region maintains low roughness for high-quality epitaxial growth, while the cutting region has high roughness to reduce stress and dislocations. This local differentiation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The substrate is segmented into distinct functional zones: device-disposed regions for growing epitaxial layers and cutting regions for subsequent dicing operations. Patterned structures are selectively placed in cutting regions to manage stress and dislocations, while device regions remain flat for optimal epitaxial quality. This segmentation resolves the contradiction by assigning different structural characteristics to different functional areas.
2Reliability
If patterned structures are added to reduce stress and dislocations, then epitaxial quality improves, but the substrate manufacturing process becomes more complex
Solution Approach 1:
Patterned structures are pre-formed on the substrate before epitaxial growth begins. These structures proactively manage stress and dislocation generation during subsequent manufacturing steps, preventing defects rather than correcting them later. This preliminary action improves device reliability while keeping the overall process manageable.
Solution Approach 2:
The patterned structures act as intermediary elements between the substrate and the epitaxial layer. They mediate the stress and dislocation transmission, reducing their harmful effects on the epitaxial growth. This intermediary approach improves reliability without requiring fundamental changes to the epitaxial process itself.
3Manufacturing precision
If the cutting region has high surface roughness to reduce stress, then threading dislocations decrease, but the overall substrate surface becomes less uniform
Solution Approach 1:
Surface roughness is locally optimized for different functional regions. The cutting region has high roughness to reduce stress and dislocations, while the device-disposed region maintains low roughness for uniform epitaxial growth. This local quality differentiation allows the substrate to achieve both stress reduction and surface uniformity where needed.
Solution Approach 2:
The substrate surface is segmented into cutting regions with high roughness and device-disposed regions with low roughness. This segmentation allows each region to have the surface characteristics optimal for its specific function, resolving the contradiction between stress reduction and surface uniformity by applying different roughness levels to different areas.
Data Source
AI summary
A patterned substrate includes a main base and a plurality of patterned structures. The main base has at least one device-disposed region and a cutting region surrounding the device-disposed region. The patterned structures are integratedly formed with the main base, and only distributed in the cutting region of the main base. The patterned structures are separated from each other.