Laser Cleavage of Sapphire Substrates for LED Manufacturing
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Solution Overview
Problem
Existing methods for manufacturing semiconductor light-emitting elements, such as LEDs, face challenges in achieving efficient cleavage of sapphire substrates while minimizing damage to the semiconductor layers, as forming multiple modified areas can deteriorate the layers, while forming a single area may result in insufficient cleavage.
Innovation Solution
A method involving the condensation of a laser beam inside the substrate to form both first and second modified portions along planned and offset cleavage lines, facilitating crack development and easy cleavage without excessive laser beam power, which reduces semiconductor layer deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple modified areas are formed in the thickness direction of the sapphire substrate, then the cleavability of the substrate is improved, but the semiconductor layer deteriorates due to laser beam damage
Solution Approach 1:
The patent divides the single modified area into multiple modified areas positioned at different depths within the sapphire substrate. This segmentation allows cracks to propagate through multiple controlled paths, improving cleavability while distributing the laser energy impact to minimize damage to the semiconductor layer.
Solution Approach 2:
The patent transitions from forming modified areas only in the thickness direction to creating a three-dimensional distribution of modified areas with different depth positions. By controlling the depth positions of multiple modified areas, the patent enables effective crack propagation through the substrate while reducing the need for excessive laser power that would damage the semiconductor layer.
2Object-affected harmful factors
If a single modified area is formed in the thickness direction of the substrate, then the semiconductor layer is protected from laser damage, but the cleavage is insufficient
Solution Approach 1:
The patent segments the single modified area into multiple modified areas at different depths. This segmentation enables the crack to propagate through multiple controlled paths within the substrate, achieving sufficient cleavage while maintaining protection of the semiconductor layer by distributing the laser energy impact.
Solution Approach 2:
The patent changes the depth position parameter of the modified areas within the substrate. By forming multiple modified areas at different depth positions rather than a single modified area, the patent achieves both sufficient cleavage and protection of the semiconductor layer through optimized energy distribution.
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 ease of substrate cleavage by promoting efficient crack propagation while minimizing damage to the semiconductor layers, allowing for effective singulation of light-emitting elements with improved cleavability and reduced layer deterioration.
Implementation Method 1
irradiating the sapphire substrate with a laser beam from the back side of the sapphire substrate to form a modified area inside the sapphire substrate
Implementation Method 2
condensing a laser beam inside a substrate provided with a semiconductor structure to form a plurality of modified portions
Implementation Method 3
generating a crack from the modified area to perform cleavage
Implementation Method 4
development of the cracks generated from the first modified portions
Data Source
AI summary
A method of manufacturing a light-emitting element includes condensing a laser beam inside a substrate provided with a semiconductor structure to form modified portions including first and second modified portions, including scanning the substrate along a predetermined planned cleavage line to form the first modified portions on the planned cleavage line inside the substrate and cracks generated from the first modified portions, and then scanning the substrate with a laser beam along a first predetermined imaginary line parallel to the planned cleavage line in a top view and is offset from the planned cleavage line in an in-plane direction of the substrate by a predetermined distance to perform second irradiation to form the second modified portions on the first predetermined imaginary line inside the substrate to facilitate development of the cracks generated from the first modified portions. The method then includes cleaving the substrate starting from the first modified portions.