Nitride Semiconductor Light Emitting Device Fabrication Process

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Solution Overview

Problem

Existing methods for working nitride semiconductor light emitting devices, such as laser processing and dry etching, often lead to device characteristic deterioration and low production yields due to high temperatures and corrosive etching conditions, particularly affecting electrode formation and light extraction efficiency.

Innovation Solution

Performing laser working and post-laser etching treatment before electrode formation, while using inclined etching surfaces to enhance light extraction and prevent electrode damage, thereby increasing device yield and light extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If laser working is used to work device shapes, then working speed and throughput are improved, but the sample is subjected to high temperature in proximity to the working site causing electrode deterioration

Engineering Contradiction:
Improveworking speedVSAvoidhigh temperature effect on electrode
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing the laser working and etching treatment before electrode formation. This sequence ensures that the harmful high temperature effects and etching exposure occur only on the semiconductor substrate, not on the electrodes. The electrodes are formed after these processes are complete, so they are not subjected to thermal damage or corrosion, thereby maintaining electrode integrity while still achieving high productivity through efficient laser working.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If dry etching with plasma is used to work nitride semiconductors, then etching capability is improved, but the working sections are exposed to several 100°C and halogen causes extensive corrosion of electrodes

Engineering Contradiction:
Improveetching capabilityVSAvoidtemperature exposure and halogen corrosion
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent performs the dry etching process before electrode formation, so the halogen-based plasma and associated temperature exposure affect only the nitride semiconductor substrate. The electrodes are not yet present during this aggressive etching process, eliminating corrosion risks. After etching is complete and the substrate is prepared, electrodes are then formed in a gentler process environment that does not expose them to harmful halogens or high temperatures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the harmful elements (high temperature exposure and halogen corrosion) from the electrode formation process by separating the etching step from electrode formation. The aggressive etching conditions are applied only to the substrate in an earlier process step, while electrode formation occurs separately under milder conditions, thus protecting the electrodes from damage while maintaining effective etching capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If laser working and etching treatment are performed after electrode formation, then device shape working is completed, but electrode surfaces deteriorate and device characteristics are impaired

Engineering Contradiction:
Improvedevice shape workingVSAvoiddevice characteristics
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent reverses the conventional sequence by performing device shape working through laser working and etching treatment before electrode formation. This preliminary action ensures that all aggressive processing occurs on the substrate alone, creating the desired device shapes and structures. Only after these processes are complete and the substrate is properly prepared are the electrodes formed, ensuring that electrode surfaces remain intact and device characteristics are maintained.

Inventive Principle:
Principle #10Preliminary action

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 electrode deterioration and enhances light extraction efficiency, improving the production yield and output of nitride semiconductor light emitting devices by optimizing the working process and surface geometry.

Implementation Method 1

Laser working involves locally heating the working site to ultrahigh temperature and accomplishing working by ablasion and vaporization

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

accomplishing working by ablasion and vaporization

Methodology Applied
Scientific EffectAblation: Ablation

Implementation Method 3

accomplishing working by ablasion and vaporization

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 4

using inclined etching surfaces to enhance light extraction

Methodology Applied
Scientific EffectLight extraction enhancement through inclined surface: Refraction

Data Source

PatentEP1929549B1Process for fabrication of nitride semiconductor light emitting device
Publication Date: 2016.07.27 TOYODA GOSEI CO LTD
  • EP1929549B1 patent drawingFigure 1~2
  • EP1929549B1 patent drawingFigure 3~4

AI summary

It is an object of the present invention to prevent device characteristic deterioration and increase device production yields by a process of laser working which has a high throughput, as means for working of device shapes, and etching as treatment after laser working. The present invention relates to a process for fabrication of a nitride semiconductor light emitting device comprising a substrate, a nitride semiconductor layer on the substrate and electrodes on the nitride semiconductor, the process for fabrication of a nitride semiconductor light emitting device being characterized by device working by laser, followed by etching treatment and then electrode formation.