Vertical GaN LED Plating Structure for Bending and Short-Circuit Prevention
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Solution Overview
Problem
Conventional vertical GaN-based LEDs face reliability issues due to structural bending and short-circuiting during manufacturing, particularly when using a structure support layer with a large thickness, and suffer from a piezoelectric effect caused by the reflecting electrode, which degrades their performance.
Innovation Solution
The solution involves forming a vertical GaN-based LED with a conductive substrate, a metal seed layer, and a current blocking layer, along with a specific plating structure to prevent structural bending and short-circuits, and localizing the reflecting electrodes under the p-type GaN-based semiconductor layer to reduce the piezoelectric effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a structure support layer with large thickness is formed between light emission structures, then mechanical support is improved, but the overall structure bends due to thermal expansion coefficient difference
Solution Approach 1:
The structure support layer is divided into multiple discrete support structures positioned between light emission structures rather than forming a continuous thick layer. This segmentation reduces the overall thickness and thermal mass, minimizing bending while maintaining localized mechanical support where needed.
Solution Approach 2:
The structure support layer is formed with varying thickness or presence only in specific regions between light emission structures rather than uniformly across the entire substrate. This local quality approach provides mechanical support only where structurally necessary, reducing overall thermal expansion effects.
2Strength
If a thick structure support layer is used, then support function is improved, but dicing or laser scribing process damages the light emission structure
Solution Approach 1:
The structure support layer is segmented into discrete regions rather than a continuous thick layer, allowing dicing or laser scribing to pass through gaps between support structures without damaging light emission structures.
Solution Approach 2:
The structure support layer is removed or reduced in thickness in regions where dicing or laser scribing paths will pass, extracting the support function only from areas where it is strictly necessary for mechanical stability.
3Use of energy by moving object
If a reflecting electrode is formed on the p-type GaN-based semiconductor layer, then light reflection is improved, but piezoelectric effect occurs degrading reliability
Solution Approach 1:
The reflecting electrode is removed from direct contact with the p-type GaN-based semiconductor layer, extracting the harmful piezoelectric effect while attempting to preserve light reflection function through alternative positioning or material selection.
Solution Approach 2:
An intermediate layer is introduced between the reflecting electrode and the p-type GaN-based semiconductor layer to mediate the interaction, reducing piezoelectric effect while maintaining light reflection efficiency.
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 reliability of the LED by preventing structural damage during processing and reducing the piezoelectric effect, leading to improved manufacturing efficiency and performance.
Implementation Method 1
electroplating or electroless plating is performed by using the metal seed layer 160 such that a structure support layer 170 composed of a plated layer is formed
Implementation Method 2
electroplating or electroless plating is performed by using the metal seed layer 160 such that a structure support layer 170 composed of a plated layer is formed
Implementation Method 3
the sapphire substrate 110 is separated from the light emission structures 210 through an LLO process
Data Source
AI summary
A method of manufacturing a vertical GaN-based LED comprises forming a light emission structure in which an n-type GaN-based semiconductor layer, an active layer, and a p-type GaN-based semiconductor layer are sequentially laminated on a substrate; etching the light emission structure such that the light emission structure is divided into units of LED; forming a p-electrode on each of the divided light emission structures; filling a non-conductive material between the divided light emission structures; forming a metal seed layer on the resulting structure; forming a first plated layer on the metal seed layer excluding a region between the light emission structures; forming a second plated layer on the metal seed layer between the first plated layers; separating the substrate from the light emission structures; removing the non-conductive material between the light emission structures exposed by separating the substrate; forming an n-electrode on the n-type GaN-based semiconductor layer; and removing portions of the metal seed layer and the second plated layer between the light emission structures.