Sapphire Substrate Division for LED Chips
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Solution Overview
Problem
The challenge in manufacturing semiconductor light-emitting devices is the occurrence of chipping and poor separation during the scribing process of sapphire substrates, which can lead to leakage in LED chips due to the rigidity of sapphire substrates and the difficulty in cleaving along the correct crystal planes.
Innovation Solution
A method involving the formation of first and second dividing grooves with specific widths and orientations on the sapphire substrate, where the first groove is parallel to the a-axis and the second groove is parallel to the m-axis, allowing for controlled cleavage to prevent chipping and leakage by aligning the long side with the easily cleaved plane and using laser irradiation to form altered portions for precise division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a scribing method is used to divide the sapphire substrate, then the substrate can be divided into multiple sections, but small cracks are generated and chipping occurs due to the rigidity of sapphire
Solution Approach 1:
The substrate division process is segmented into two distinct stages: first forming dividing grooves along the a-axis direction (easily cleaved planes) to create initial separation paths, then forming dividing grooves along the m-axis direction to complete the rectangular chip separation. This segmentation allows each cutting direction to be optimized independently, preventing chipping while maintaining productivity.
Solution Approach 2:
The patent applies preliminary action by first forming dividing grooves along the a-axis direction (the easily cleaved plane) before forming grooves along the m-axis direction. This preliminary grooving creates controlled weak points in the rigid sapphire substrate, allowing subsequent cleavage to proceed without generating harmful cracks or chipping.
2Shape
If cleavage is performed along the m-axis direction for the long side of the LED chip, then rectangular chips can be formed, but chipping or poor separation occurs because cleavage is not performed along the easily cleaved plane
Solution Approach 1:
The patent applies asymmetry by treating the two directions of substrate division differently: the a-axis direction (short side) uses simple cleavage along the easily cleaved plane, while the m-axis direction (long side) requires preliminary groove formation followed by cleavage. This asymmetric approach optimizes each direction according to the sapphire crystal structure's properties, ensuring both rectangular chip shape and high separation 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 method effectively prevents chipping and leakage by facilitating easy cleavage along the a-axis direction for the long side and using a wider groove along the m-axis direction for the short side, ensuring the integrity of the light-emitting device sections during the substrate division process.
Implementation Method 1
using laser irradiation to form altered portions for precise division
Data Source
AI summary
A method of manufacturing a semiconductor light-emitting device which includes the steps of forming a plurality of light-emitting device sections (40), having an approximately rectangular shape in plan view, on a substrate (10) in a matrix shape, forming a first dividing groove (61) between the long sides (41) of the light-emitting device sections (40) so that the long side (41) of the light-emitting device section (40) is along an easily cleaved plane of the substrate (10), forming a second dividing groove (62), having a larger width than the width of the first dividing groove (61), between short sides (42) of the light-emitting device sections (40), and dividing the substrate (10) along a first dividing groove (61) and a second dividing groove (62) to cut out the light-emitting device section (40).