Optoelectronic Device Substrate Removal via Selective Etching

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Solution Overview

Problem

Existing methods for manufacturing optoelectronic devices with light-emitting diodes or photodiodes often result in structural degradation due to substrate removal processes, leading to unevenness and inhomogeneities that affect the device's performance and reliability.

Innovation Solution

A method involving a growth substrate with distinct doping levels for the lower and upper parts, where the lower part is selectively chemically etched to remove the substrate uniformly, reducing structural degradation and maintaining the upper part's thickness for even substrate removal, thus preserving the device's structure and enhancing its mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the growth substrate is completely removed by chemical etching or erosion, then the substrate can be fully removed to allow LED assembly, but structural degradation occurs leading to unevenness and inhomogeneities

Engineering Contradiction:

Improvesubstrate removal completenessVSAvoidstructural uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The substrate is divided into two distinct parts: a lower part with high doping concentration that is removed by chemical etching, and an upper part with low doping concentration that remains as a support structure. This segmentation allows complete removal of the growth substrate while preserving structural integrity through the retained upper part.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the substrate are given different doping concentrations to serve different functions. The lower part has high doping for easy chemical removal, while the upper part has low doping for structural support and uniform thickness maintenance during the etching process.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the substrate is removed by chemical etching, then the substrate can be eliminated, but thickness inhomogeneities and structural degradation are caused

Engineering Contradiction:

Improvesubstrate removal easeVSAvoidthickness uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The substrate is pre-structured with differential doping concentrations before the chemical etching process. The lower part is prepared with high doping to be selectively removed, while the upper part is prepared with low doping to maintain uniform thickness and prevent structural degradation during etching.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The doping concentration parameter is changed across different parts of the substrate. The lower part has high doping concentration for easy chemical removal, while the upper part has low doping concentration to maintain structural integrity and uniform thickness during the etching process.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the entire substrate is removed, then the LEDs can be freely assembled, but mechanical strength and structural integrity are compromised

Engineering Contradiction:

ImproveLED assembly flexibilityVSAvoiddevice mechanical strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The substrate is segmented into a removable lower part and a retained upper part. The lower part is completely removed by chemical etching to enable LED assembly, while the upper part with low doping concentration remains as a mechanically strong support structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The upper part of the substrate acts as an intermediary structure that remains after etching. It serves as both a mechanical support to maintain device strength and a platform for LED assembly, bridging the gap between complete substrate removal and structural integrity requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 structural damage during substrate removal, ensuring a uniform residual layer and improved mechanical strength, which enhances the optoelectronic device's performance and reliability by eliminating thickness inhomogeneities and maintaining the device's structural integrity.

Implementation Method 1

step c) involving the removal of the lower part by selective chemical etching with respect to the upper part

Methodology Applied

Scientific EffectSelective chemical etching:

Data Source

PatentEP3563426B1Method for producing an optoelectronic device comprising a step of etching the rear face of the growth substrate

Publication Date: 2020.11.18 ALEDIA INC

Figure 1A~1C
Figure 2A~2D
Figure 2E~2G

AI summary

The invention relates to a method for manufacturing an optoelectronic device (1), comprising the following steps: a) providing a growth substrate (10) made from a semiconductor material; b) forming a plurality of diodes (20) each comprising a lower face (20i); c) removing at least a portion (12; 13) of the substrate so as to free the lower face (20i); wherein: - step a) involves producing a lower part and an upper part of the substrate, the upper part (12) having a uniform thickness (eref) and a level of doping less than that of the lower part; - step c) involving removal of the lower part (11) by selective chemical etching with respect to the upper part (12).