Supporting Substrate for Semiconductor Light Emitting Device Fabrication

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Solution Overview

Problem

The existing methods for manufacturing Group III-V nitride-based semiconductor light-emitting devices face challenges such as damage to the semiconductor single crystal multi-layered light-emitting structure thin film during the separation process from sapphire substrates due to mechanical stress, leading to reduced chip yield and performance, and limitations in heat dissipation and static electricity management.

Innovation Solution

A method involving wafer bonding using a thermo-compression bonding method at controlled temperatures and pressures, combined with chemo-mechanical polishing or wet etching, to separate the multi-layered light-emitting structure thin film from the sapphire substrate, utilizing a supporting substrate with a heat-sink layer and sacrificial layer to minimize stress and facilitate efficient heat dissipation and static electricity prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the multi-layered light-emitting structure thin film is separated from the sapphire substrate through laser lift off process, then the light-emitting device can be manufactured, but the semiconductor single crystal multi-layered light-emitting structure thin film is damaged due to mechanical stress

Engineering Contradiction:
Improvelight-emitting device manufacturingVSAvoidthin film integrity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A supporting substrate is introduced as an intermediary between the sapphire substrate and the multi-layered light-emitting structure. The supporting substrate has a thermal expansion coefficient matched to the light-emitting structure, providing mechanical support during separation and preventing damage while enabling successful device manufacturing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The supporting substrate is bonded to the light-emitting structure before the separation process. This pre-positioned support structure cushions and absorbs the mechanical stress that would otherwise damage the thin film during laser lift off, ensuring integrity while enabling manufacturing

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If sapphire substrate is used as initial substrate, then high quality semiconductor thin films can be grown, but heat dissipation is poor and static electricity management is difficult

Engineering Contradiction:
Improvesemiconductor thin film qualityVSAvoidheat dissipation capability
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The supporting substrate acts as a thermal management intermediary, replacing the insulating sapphire substrate with a material that provides both mechanical support and improved thermal conductivity, enabling efficient heat dissipation while maintaining thin film quality

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal expansion coefficient and thermal conductivity parameters of the substrate are changed by transitioning from sapphire to a supporting substrate with matched thermal expansion properties and superior heat dissipation capability, resolving both the quality and thermal management issues

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If sapphire substrate is used, then semiconductor thin films can be grown, but the substrate is difficult to respond to static electricity and reliability is reduced

Engineering Contradiction:
Improvethin film growth qualityVSAvoidstatic electricity response
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The supporting substrate serves as an intermediary that provides both the mechanical support needed for thin film growth and the electrical properties needed for static electricity management, eliminating the reliability issues of sapphire while preserving manufacturing quality

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from a single material (sapphire) to a composite structure where the supporting substrate combines the necessary mechanical support properties with superior electrical conductivity for static electricity response, enhancing both quality and reliability

Inventive Principle:
Principle #40Composite materials

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 minimizes micro-crack and breaking of the semiconductor layers, enhances chip yield, and allows for reliable, high-performance light-emitting devices with improved thermal management and static protection, enabling the production of high-quality vertical-structured LEDs.

Implementation Method 1

utilizing a supporting substrate with a heat-sink layer and sacrificial layer to minimize stress

Methodology Applied
Scientific EffectStress absorption: Elasticity

Implementation Method 2

heat-sink layer to minimize stress and facilitate efficient heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

separating/removing the multi-layered light-emitting structure thin film from the initial substrate through the laser lift off

Methodology Applied
Scientific EffectLaser lift off: Laser Ablation

Data Source

PatentEP2302705B1Supporting substrate for fabrication of semiconductor light emitting device and semiconductor light emitting device using the same
Publication Date: 2018.03.14 LG INNOTEK CO LTD
  • EP2302705B1 patent drawingFigure 1
  • EP2302705B1 patent drawingFigure 2(a)~2(b)
  • EP2302705B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention is related to a supporting substrate for preparing a semiconductor light-emitting device employing a multi-layered light-emitting structure thin-film and a method for preparing a semiconductor light-emitting device employing the supporting substrate for preparing a semiconductor light-emitting device. The supporting substrate for preparing a semiconductor light-emitting device is formed by successively laminating a sacrificial layer, a heat-sink layer and a bonding layer on a selected supporting substrate. A method for preparing a semiconductor light-emitting device employing the supporting substrate for preparing a semiconductor light-emitting device includes: preparing a first wafer in which a semiconductor multi-layered light-emitting structure is laminated/grown on an upper part of an initial substrate; preparing a second wafer which is a supporting substrate for preparing a semiconductor light-emitting device; bonding the second wafer on an upper part of the first wafer; separating the initial substrate of the first wafer from a result of the bonding; performing passivation after forming a first ohmic contact electrode on an upper part of the first wafer from which the initial substrate is separated; and preparing a single-chip by severing a result of the passivation.