Inclined Insulating Reflective Layer for LED Warpage and Light Extraction
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Solution Overview
Problem
Existing light-emitting devices face challenges in reliability due to issues such as warpage during manufacturing, stress on semiconductor structures, and inefficiencies in light extraction and inspection processes.
Innovation Solution
A light-emitting device design featuring a substrate with an uneven structure, a semiconductor structure with a specific layout, and an insulating reflective layer with an inclined lateral surface, which reduces warpage, enhances light extraction, and improves inspection reliability by optimizing the reflection and detection of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the insulating reflective layer has a vertical lateral surface, then the manufacturing process is simpler, but light extraction efficiency is reduced due to total internal reflection at the substrate interface
Solution Approach 1:
The patent changes the geometric parameter of the insulating reflective layer from a vertical lateral surface to an inclined lateral surface with a specific angle range (15°-75° relative to the substrate upper surface). This parameter modification enables the layer to function both as a reflector and as a light extraction enhancer by allowing light to escape at angles that avoid total internal reflection, while maintaining manufacturing feasibility through standard photolithography and etching processes.
2Productivity
If automated optical inspection is performed on light-emitting devices with reflective layers, then manufacturing quality can be monitored, but inspection accuracy is reduced due to light reflection interfering with detection
Solution Approach 1:
The patent applies local quality by creating a region-specific structure where the insulating reflective layer has an inclined lateral surface at its peripheral end. This localized geometric modification serves dual purposes: it maintains the reflective function in the core area while creating a light extraction path at the periphery that allows inspection light to penetrate and detect defects without being completely blocked by reflection, thereby enabling both quality monitoring and maintaining inspection accuracy.
3Volume of moving object
If the semiconductor structure is positioned close to the substrate edge, then device size is reduced, but warpage occurs during manufacturing processes
Solution Approach 1:
The patent applies preliminary action by forming the insulating reflective layer with an inclined lateral surface before final device assembly and inspection processes. This pre-formed structure serves as a stress distribution element that compensates for warpage forces that will occur during subsequent manufacturing steps, allowing the semiconductor structure to be positioned closer to the substrate edge while maintaining overall structural stability throughout the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances the reliability of light-emitting devices by reducing warpage, improving light extraction efficiency, and facilitating effective automated optical inspection through enhanced light reflection and detection.
Implementation Method 1
The insulating reflective layer covers at least a part of the semiconductor structure and has an extending portion extending outwardly from the semiconductor structure and covering a part of the upper surface of the substrate. A peripheral end of the extending portion of the insulating reflective layer has an inclined lateral surface
Data Source
AI summary
A light-emitting device includes a substrate, a semiconductor structure, and an insulating reflective layer. The substrate has an upper surface and a lower surface. The semiconductor structure is disposed on the upper surface of the substrate. A projection of the semiconductor structure on the upper surface of the substrate has an outer periphery spaced apart a distance from an outer periphery of the upper surface of the substrate. The insulating reflective layer covers at least a part of the semiconductor structure and has an extending portion extending outwardly from the semiconductor structure and covering a part of the upper surface of the substrate. A peripheral end of the extending portion of the insulating reflective layer has an inclined lateral surface, and an included angle defined between the inclined lateral surface and the upper surface of the substrate is not less than 60°.