Axial 3D LED Optoelectronic Device Stacking for Compact Integration

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Solution Overview

Problem

The challenge lies in manufacturing optoelectronic devices with three-dimensional light-emitting diodes in axial configuration, which have a lower emission surface and better crystalline quality, but are difficult to produce with reduced lateral dimensions, especially less than 5 μm, and require a method that aligns with the manufacturing of planar light-emitting diodes.

Innovation Solution

A method involving the formation of first and second three-dimensional semiconductor elements with specific dimensions and pitches, integrated with electrically conductive layers and active areas, to create a compact optoelectronic device with enhanced quantum efficiency, where the semiconductor elements are made of III-V compounds and emit radiation at different wavelengths, and the device is assembled by attaching an optoelectronic circuit to a control circuit with conductive pads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If three-dimensional light-emitting diodes in axial configuration are used, then internal quantum efficiency is improved, but manufacturing difficulty increases for reduced lateral dimensions

Engineering Contradiction:
Improveinternal quantum efficiencyVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The device is divided into separate functional modules: a first electronic circuit containing the three-dimensional light-emitting diodes in axial configuration, and a second electronic circuit for control and signal processing. This segmentation allows each module to be optimized and manufactured separately, then integrated through wire bonding, thereby reducing the overall manufacturing difficulty while preserving the high internal quantum efficiency of the axial configuration LEDs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from planar integration to three-dimensional stacking architecture. The first electronic circuit with axial LEDs is stacked above the second electronic circuit, with vertical wire bonds connecting the two layers. This dimensional change enables compact integration while maintaining the manufacturing advantages of axial configuration LEDs by separating their fabrication from the control circuit fabrication.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If lateral dimension is reduced to less than 5 μm, then device compactness is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvedevice compactnessVSAvoidlateral dimension precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent achieves device compactness by stacking electronic circuits in the vertical dimension rather than shrinking lateral dimensions. The first electronic circuit with axial LEDs is positioned above the second electronic circuit, connected by vertical wire bonds. This approach provides compactness in the Z-direction while allowing standard manufacturing precision to be maintained in the lateral X-Y directions, avoiding the need for sub-5 μm lateral precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Different regions of the device are assigned different dimensional characteristics: the light-emitting region uses axial configuration LEDs with optimized vertical geometry for compactness, while the interconnection region uses wire bonds with controlled lateral positioning. This local differentiation allows compactness where needed without imposing stringent precision requirements across the entire device structure.

Inventive Principle:
Principle #3Local quality

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

The method enables the production of compact optoelectronic devices with reduced lateral dimensions, achieving higher internal quantum efficiency and allowing for the emission of radiation at various wavelengths, thereby improving the display capabilities of optoelectronic devices.

Implementation Method 1

first active zones resting on the ends of the first three-dimensional semiconductor elements opposite the first electrically conductive layer and adapted to emit or capture a first electromagnetic radiation at a first wavelength

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3646383B1Optoelectronic device comprising three-dimensional semiconductor structures in an axial configuration
Publication Date: 2022.08.17 ALEDIA INC
  • EP3646383B1 patent drawingFigure 1~7
  • EP3646383B1 patent drawingFigure 8A~8D
  • EP3646383B1 patent drawingFigure 8E~8H

AI summary

The invention relates to an optoelectronic device (10) comprising a first optoelectronic circuit (12) attached to a second electronic circuit (14). The second electronic circuit (14) comprises conductive pads (62). The first optoelectronic circuit comprises, for each pixel: at least first and second three-dimensional semiconductor elements (20, 22) extending over a first conductive layer and being of the same height (H); first active areas resting on the first semiconductor elements and suitable for emitting or receiving first electromagnetic radiation; second active areas resting on the second semiconductor elements and suitable for emitting or receiving second electromagnetic radiation; and second, third and fourth conductive layers (42, 44, 48) electrically connected to the conductive pads (62), the second, third and fourth conductive layers being connected respectively to the first active areas, to the second active areas and to the first conductive layer.