LED Barrier Layer Protection Against HF Etching During Substrate Removal

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Solution Overview

Problem

In high-power horizontal structure LED dies, the current blocking layer (CBL) made of SiO2 is prone to etching away during the HF immersion process for removing temporary substrates, leading to structural instability and quality issues of the light-emitting diode.

Innovation Solution

A light emitting diode structure is designed with a semiconductor stack layer, an insulative barrier layer, and a metal protective layer, where the metal protective layer is connected to the outermost side of the insulative barrier layer, ensuring it remains intact during fabrication processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the current blocking layer covers the entire surface to insulate and separate the conductive structure from the epitaxial layer, then the uniformity of current flow and luminous efficiency are improved, but the insulative barrier layer is easily etched away during HF immersion process causing structural instability

Engineering Contradiction:

Improvestructural stabilityVSAvoidetching damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a metal protective layer as an intermediary between the insulative barrier layer and the HF immersion environment. This protective layer acts as a barrier that prevents HF from directly contacting and etching the insulative barrier layer, thereby resolving the contradiction between maintaining full surface coverage for electrical insulation and preventing etching damage during fabrication.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The metal protective layer is applied in advance before the HF immersion process to provide preemptive protection. By establishing this protective barrier beforehand, the insulative barrier layer is shielded from potential etching damage, allowing the structure to maintain its integrity throughout the fabrication process.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the current blocking layer covers the entire surface, then current uniformity is improved, but the layer falls off during HF immersion process affecting LED quality

Engineering Contradiction:

Improvecurrent distribution uniformityVSAvoidlayer adhesion

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The metal protective layer serves as an intermediary that protects the insulative barrier layer from HF etching. This allows the insulative barrier layer to maintain its full surface coverage configuration for current uniformity while the protective layer prevents the adhesion failure that would otherwise occur during HF immersion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If SiO2 material is used for the current blocking layer, then electrical insulation is achieved, but the layer is vulnerable to HF etching during substrate removal

Engineering Contradiction:

Improveelectrical insulation performanceVSAvoidHF etching susceptibility

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The metal protective layer acts as an intermediary barrier that protects the SiO2 insulative barrier layer from HF etching. This allows the use of SiO2 material for its excellent electrical insulation properties while the protective layer prevents the harmful interaction between HF and SiO2 during the substrate removal process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure employs a composite material approach by combining the insulative barrier layer (SiO2) with the metal protective layer. This composite structure leverages the electrical insulation properties of SiO2 while adding the HF resistance properties of the metal layer, thereby resolving the vulnerability to HF etching.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250040308A1Light emitting diode and light emitting device

Publication Date: 2025.01.30 TIANJIN SANAN OPTOELECTRONICS

AI summary

A light emitting diode includes a semiconductor stack layer, an insulative barrier layer, and a metal protective layer. The semiconductor stack layer includes a first semiconductor layer, a light emitting layer, and a second semiconductor layer. The insulative barrier layer is disposed on a lower surface of the semiconductor stack layer and has a first opening corresponding to a lower side of the first semiconductor layer. The metal protective layer is disposed on the lower surface of the semiconductor stack layer and connected to the insulative barrier layer. A portion of the metal protective layer is filled in the first opening. Vertical projection points of edge endpoints of an upper surface of the insulative barrier layer on a horizontal plane are distributed within a vertical projection first connecting line section of edge endpoints of an upper surface of the metal protective layer on the horizontal plane.