LED Substrate Scribing via Laser Ablation and Etching
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Solution Overview
Problem
The scribing process for manufacturing light emitting diodes (LEDs) often damages the substrate or compound semiconductor, leading to reduced light efficiency due to absorption of light at the damaged regions.
Innovation Solution
A method involving the formation of a mask layer on the semiconductor layer, selective laser irradiation to create scribing regions, and subsequent etching to remove damaged areas, while minimizing the etching of the semiconductor layer, thereby improving light efficiency by preventing light absorption at the damaged regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser irradiation is applied to the substrate or compound semiconductor during the scribing process, then the substrate or compound semiconductor adjacent to the scribing region is damaged, but light efficiency is degraded due to light absorption at the damaged regions
Solution Approach 1:
The patent segments the scribing process into two distinct stages: first, laser irradiation creates initial scribing regions to divide the substrate; second, etching removes the damaged regions. This segmentation allows the harmful laser damage to be isolated and subsequently eliminated, resolving the contradiction between manufacturing ease and light efficiency
Solution Approach 2:
The patent converts the harmful laser-induced damage into a beneficial etching marker. The damaged regions created by laser irradiation serve as precise targets for subsequent etching, allowing the harmful effect to be transformed into a useful guide for removing defective areas and improving overall light efficiency
2Loss of energy
If the scribing region is etched to remove damaged areas, then light efficiency is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary laser irradiation to create clearly defined scribing regions before etching. This preliminary action marks the exact areas that need removal, making the subsequent etching process more precise and efficient, thereby justifying the added process step through improved outcome quality
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 light efficiency by ensuring that light emitted from the active layer can pass through undamaged regions, resulting in improved LED performance.
Implementation Method 1
irradiating laser onto a scribing region of the mask layer to divide the semiconductor layer into a plurality of light emitting diodes
Implementation Method 2
etching the scribing region
Data Source
AI summary
A light emitting device is provided, including a substrate and a light emitting structure on the substrate, comprising a first semiconductor layer, a second semiconductor layer on the first semiconductor layer, and an active layer between the first and second semiconductor layers. The substrate has at least one side surface extending outwardly. The at least one side surface includes a first portion, a transition portion connected to the first portion, and a second portion connected to the transition portion, the first portion provides a first obtuse inclination angle with reference to the bottom surface of the substrate and the transition portion provides a second obtuse inclination angle with reference to the bottom surface of the substrate, the second obtuse inclination angle is larger than the first obtuse inclination angle. The second portion includes a vertical side surface with reference to the bottom surface of the substrate.