LED Wafer Dicing with Reflective Structure
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Solution Overview
Problem
Conventional wafer dicing methods for light-emitting diodes (LEDs) suffer from reduced yield and potential damage to the semiconductor stack due to narrow dicing streets and improper laser power control, leading to degraded performance and efficiency.
Innovation Solution
A method involving the formation of a semiconductor wafer with a substrate and semiconductor stack, where a first reflective structure is created on the exposed region to guide and reflect radiation, preventing damage to the stack during the dicing process, and allowing for precise separation into light-emitting device chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional dicing methods are used with narrow dicing streets, then device integration is improved, but dicing yield deteriorates
Solution Approach 1:
The patent applies preliminary action by forming a sacrificial layer and defining isolation trenches before the dicing process. This pre-prepared structure enables clean separation along predetermined paths, preventing damage to the semiconductor stack during dicing while maintaining narrow dicing streets for high device integration.
2Productivity
If laser power is increased for effective wafer dicing, then dicing efficiency is improved, but damage to semiconductor stack worsens
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary that absorbs the laser energy during dicing. This layer acts as a mediator between the laser beam and the semiconductor stack, allowing effective dicing with sufficient laser power while protecting the semiconductor stack from damage through the protective effect of the sacrificial material.
Solution Approach 2:
The patent converts the potentially harmful laser energy into a beneficial cutting mechanism by directing it through the sacrificial layer. The laser energy that would otherwise damage the semiconductor stack is instead used to cleanly separate the sacrificial layer along the dicing streets, achieving efficient dicing without harm to the device.
3Quantity of substance
If dicing streets are narrowed to increase chip density, then chip density is improved, but dicing yield deteriorates
Solution Approach 1:
The patent forms isolation trenches and sacrificial layer structures before dicing, creating predetermined separation paths. This preliminary preparation enables narrow dicing streets to be implemented without compromising dicing yield, as the sacrificial layer provides a clean separation interface that prevents damage even in tightly spaced configurations.
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
This approach enhances the yield and reduces damage to the semiconductor stack during dicing, improving the brightness and epitaxy quality of the light-emitting devices by using a reflective structure to manage radiation and facilitate clean separation.
Implementation Method 1
forming a first reflective structure on the exposed region; and providing a radiation on the second surface corresponding to a position of the first reflective structure
Data Source
AI summary
A manufacturing method of a light-emitting device is disclosed. The method includes: providing a semiconductor wafer, including a substrate having a first surface and a second surface opposite to the first surface; and a semiconductor stack on the first surface; removing a portion of the semiconductor stack to form an exposed region; forming a first reflective structure on the exposed region; and providing a radiation on the second surface corresponding to a position of the first reflective structure.