LED Wafer Thinning via Fixing Piece Support
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Solution Overview
Problem
The existing LED manufacturing method often results in wafer warpage and substrate breakage due to residual stress, especially during the grinding and cutting processes, leading to reduced product quality and reliability.
Innovation Solution
A manufacturing method that involves fixing an LED wafer with a supporting piece before detaching it from the crafting table to maintain flatness and structural integrity, allowing for controlled thickness reduction and precise cutting to prevent damage, and optimizing the thickness ratio and beam-divergence angle for improved light centralization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate is ground to reduce thickness, then the LED size is reduced, but the substrate becomes too thin and prone to breakage
Solution Approach 1:
The substrate surface is pre-treated with sandpaper or abrasive paper before grinding to remove the high-stress epitaxial layer and create a more uniform stress distribution, preventing catastrophic failure during subsequent thinning operations
Solution Approach 2:
The substrate thickness is controlled to maintain a specific ratio (2-20 times) relative to the light-emitting unit thickness, providing a cushioning effect that prevents complete substrate failure while achieving the desired compact LED size
2Volume of moving object
If the substrate is ground to reduce thickness, then the LED size is reduced, but the wafer becomes warped due to residual stress
Solution Approach 1:
The substrate surface is pre-treated with sandpaper or abrasive paper before grinding to uniformly distribute residual stresses and eliminate the high-stress epitaxial layer, preventing warpage during subsequent thinning operations
Solution Approach 2:
The substrate thickness is controlled to maintain a specific ratio (2-20 times) relative to the light-emitting unit thickness, which optimizes the mechanical properties and stress distribution to maintain wafer flatness while achieving compact size
3Ease of manufacture
If the wafer is cut after removal from crafting table, then the LED can be separated, but the thin substrate easily breaks or damages
Solution Approach 1:
The substrate surface is pre-treated with sandpaper or abrasive paper before grinding to uniformly distribute residual stresses, preventing catastrophic failure during subsequent cutting operations
Solution Approach 2:
The substrate thickness is controlled to maintain a specific ratio (2-20 times) relative to the light-emitting unit thickness, providing a cushioning effect that prevents complete substrate failure during cutting while achieving the desired compact LED size
Data Source
AI summary
A light-emitting diode (LED) and a method for manufacturing the same are provided. The method includes following steps. An LED wafer is fixed on a crafting table and is processed such that a substrate of the LED wafer has a thickness smaller than or equal to 100 μm. A fixing piece is pasted on the LED wafer surface. The LED wafer is detached from the crafting table. The LED wafer together with the fixing piece are cut and broken, such that the LED wafer forms a plurality of LEDs. The fixing piece is removed. Before the LED wafer is detached from the crafting table, the fixing piece is pasted on the LED wafer to provide a supporting force to the LED wafer to maintain the flatness of the wafer and avoid the wafer being warped or the substrate being broken or damaged, such that product quality and reliability can be improved.