Hexagonal LED Wafer Cleaving with Multi-Direction Laser Scanning
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Solution Overview
Problem
Existing methods for manufacturing hexagonal light emitting elements face yield reduction due to cracks extending from modified regions into the light emitting element regions during wafer cleavage, leading to chipping and other damages.
Innovation Solution
A method involving laser scanning with multiple directions to form modified regions along the sides of a hexagonal shape, preventing cracks from reaching the light emitting element regions by performing first, second, and third scans in specific orientations relative to the sapphire substrate's crystal axes, followed by cleaving along these modified regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a planned cleavage line forms a grid shape in a top view of a wafer, then the crack is unlikely to reach the inside of a region of an individual light emitting element, but the light emitting element cannot have a hexagonal shape
Solution Approach 1:
The cleavage process is divided into multiple scanning operations (first scanning, second scanning, third scanning) that create modified regions along different directions. This segmentation of the cleavage path into multiple directional scans allows the formation of hexagonal shapes while preventing cracks from reaching inside the light emitting element regions.
Solution Approach 2:
The invention transitions from a simple grid-shaped cleavage line (2D planar pattern) to a multi-directional scanning approach that creates modified regions along three different directions. This dimensional change in the cleavage strategy enables hexagonal light emitting element shapes while maintaining crack prevention capabilities.
2Area of stationary object
If the light emitting element has a hexagonal shape in a top view, then the area efficiency is improved, but the possibility that the crack extending from the modified region reaches the inside of the light emitting element region increases
Solution Approach 1:
The laser scanning parameters and directions are locally optimized for each scanning operation. The first scanning, second scanning, and third scanning are performed along different directions parallel to different sides of the hexagonal shape, creating modified regions with specific local characteristics that prevent crack propagation into the light emitting element regions while maintaining hexagonal geometry.
Solution Approach 2:
The modified regions are formed in advance along the planned cleavage lines before the actual cleavage occurs. By performing multiple preliminary scanning operations to create modified regions in three different directions, the invention ensures that cracks will follow the predetermined modified region paths and not extend into the hexagonal light emitting element regions during the cleavage process.
3Manufacturing precision
If multiple scanning operations are performed to form modified regions along hexagonal sides, then the manufacturing precision is improved, but the manufacturing time increases
Solution Approach 1:
The invention employs periodic scanning operations (first scanning, second scanning, third scanning) performed in sequence along different directions. This periodic action pattern allows the system to efficiently create modified regions along all six sides of the hexagonal light emitting elements through three systematic passes, improving cleavage precision while managing manufacturing time through organized periodic operations.
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 effectively prevents cracks from entering the light emitting element regions, improving yield and reducing manufacturing defects, thus enhancing the production efficiency of hexagonal light emitting elements.
Implementation Method 1
scanning the wafer with laser light to irradiate laser light into the substrate to form a plurality of modified regions for cleaving the wafer
Data Source
Figure 1A
Figure 1B~1C
Figure 1D~1E
AI summary
The method of manufacturing a light emitting element includes: providing a wafer including a sapphire substrate and a semiconductor structure; scanning the wafer to irradiate laser light into the substrate to form modified regions for cleaving the wafer into light emitting elements having a hexagonal shape in a top view; and cleaving the wafer. The scanning of the wafer includes: a first scanning to form first modified regions along a first direction parallel to first and second sides of the hexagonal shape, a second scanning, and a third scanning. The first scanning includes a first irradiation where laser light is scanned from a first end side of the first side to a first location between first and second ends of the first side, and a second irradiation where laser light is scanned from a second end side to a second location between the second and first ends.