Etching Curved Lateral Surface on Conductive Support Member
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Solution Overview
Problem
The existing manufacturing processes for light emitting devices using III-V nitride semiconductors face challenges in achieving high yield rates due to defects caused by the breaking process after laser scribing, particularly when the conductive support member thickness exceeds a certain limit, leading to low yield rates.
Innovation Solution
An etching process is performed after the laser scribing process to reduce the thickness of the re-combination section of the conductive support member, thereby reducing defects and improving the yield rate by creating a curved lateral surface recessed inward, which helps in dividing the light emitting structure layer and conductive support member into separate chip units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the conductive support member thickness is increased to ensure structural strength, then the mechanical strength is improved, but the yield rate deteriorates due to defects caused by breaking process after laser scribing
Solution Approach 1:
The conductive support member is divided into separate portions through the laser scribing process that creates separating sections, allowing the structure to be segmented into multiple chip units. This segmentation reduces the overall stress on any single section and prevents catastrophic failure across the entire structure.
Solution Approach 2:
The re-combination section is selectively removed through etching process to create a curved lateral surface. This extraction of material at the critical re-combination zone eliminates the defect-prone area while maintaining the necessary structural integrity in other regions.
2Weight of moving object
If the laser scribing process is performed to divide the conductive support member into separate portions, then the chip unit separation is improved, but defects are generated at the re-combination section
Solution Approach 1:
The etching process acts as an intermediary step between laser scribing and final chip separation. It selectively removes the re-combination section to create a curved lateral surface, serving as a mediator that eliminates defects while preserving the separation function.
Solution Approach 2:
The etching process is performed preliminarily before the final breaking process to pre-remove the defective re-combination section. This preliminary action prevents defects from propagating during subsequent handling and separation steps.
3Reliability
If the re-combination section thickness is reduced through etching process, then the yield rate is improved, but additional manufacturing steps are required
Solution Approach 1:
The etching process changes the physical parameters of the re-combination section by selectively removing material to create a curved lateral surface with reduced thickness. This parameter change eliminates defects while the process is integrated into the existing manufacturing workflow.
Solution Approach 2:
The etching process creates an asymmetric curved lateral surface at the re-combination section rather than a uniform thickness throughout. This asymmetric geometry specifically addresses the defect-prone area while leaving other regions unchanged, adding minimal complexity.
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 etching process enhances the yield rate of light emitting device manufacturing by reducing defects and improving the structural integrity of the light emitting device, even when the conductive support member thickness is in the range of 75 μm to 500 μm, thereby increasing the reliability of the device production.
Implementation Method 1
forming a separating section, by which the conductive support is divided into separate portions, by performing a laser scribing process with respect to the chip boundary region while passing through the conductive support member
Implementation Method 2
performing an etching process with respect to the separating section, and dividing the light emitting structure layer and the conductive support member in a chip unit by breaking the conductive support member
Data Source
AI summary
Disclosed are a light emitting device, a method of manufacturing the same, a light emitting device package, and a lighting system. The light emitting device includes a conductive support member, a light emitting structure layer including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer on the conductive support member, and an electrode on the light emitting structure layer. The conductive support member has a curved lateral surface recessed inward.