Metallic Optical Separation Grid Brazing for LED Matrices

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Solution Overview

Problem

Current methods for producing optical separation grids for photo-emitting and photo-receiving devices, especially those emitting or receiving light from the rear face, face challenges in achieving good alignment and require material planarization, which complicates the process and limits the height of the optical separation grid.

Innovation Solution

A method involving the production of a metallic optical separation grid by securing it using brazing, where a metallic electrode covers the semiconductor stack and the grid is aligned through self-alignment during the soldering process, eliminating the need for material planarization and allowing for precise alignment with the device components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the optical separation grid is produced by depositing material in trenches formed by lithography, then the grid can be integrated during BEOL manufacturing, but the height of the grid is limited to between 1 μm and 3 μm

Engineering Contradiction:
Improveintegration during BEOL manufacturingVSAvoidheight of optical separation grid
Core Design Contradiction:
Ease of manufactureVSLength of moving object

Solution Approach 1:

The production process is divided into two independent stages: first producing the optical separation grid on a separate support substrate, then transferring it to the device. This segmentation allows each stage to be optimized independently, enabling greater grid height without compromising integration capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical separation grid is produced in advance on a support substrate before being transferred to the final device. This preliminary action allows the grid to be manufactured with optimal dimensions and properties, then positioned precisely during the device assembly process

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the optical separation grid is produced after substrate removal for rear-face devices, then it can be applied to rear-face emission/reception, but alignment with pixels becomes difficult

Engineering Contradiction:
Improveapplicability to rear-face devicesVSAvoidalignment with pixels
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

A support substrate acts as an intermediary carrier during the production and transfer process. The grid is first fabricated on this intermediate support, then transferred to the final device with precise alignment, enabling both rear-face applicability and manufacturing precision

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The alignment process uses optical fields and electromagnetic methods instead of purely mechanical alignment techniques. Optical alignment methods enable precise positioning of the grid relative to pixels during the transfer process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If material planarization is performed to form the optical separation grid, then the grid can be integrated with interconnection levels, but the production process becomes more complex

Engineering Contradiction:
Improveintegration with interconnection levelsVSAvoidproduction process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The optical separation grid production is extracted from the main device fabrication process and performed separately on a support substrate. This extraction eliminates the need for material planarization steps in the device process while maintaining integration capability through subsequent transfer

Inventive Principle:
Principle #2Taking out (Extraction)

4Area of stationary object

If the walls of the optical separation grid are made thin to preserve pixel surface, then the aspect ratio becomes large (greater than 2), making manufacturing difficult

Engineering Contradiction:
Improveuseful surface of pixelsVSAvoidwall verticality and roughness
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The deposition process is designed to be self-aligning, where the material automatically conforms to the desired wall geometry during deposition. This self-service mechanism produces walls with excellent verticality and surface finish without requiring complex post-processing or planarization steps

Inventive Principle:
Principle #25Self-service

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 method enables precise alignment and secure attachment of the optical separation grid without the need for planarization, improving the optical isolation and directivity of the device while simplifying the production process, suitable for high-resolution devices like LED matrices.

Implementation Method 1

securing the metallic optical separation grid against said face of the first metallic electrode by brazing

Methodology Applied
Scientific EffectBrazing: Brazing

Implementation Method 2

The light-emitting and/or light-receiving component may comprise at least one light-emitting and/or light-receiving diode

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

treatment of at least one face of the first metallic electrode located at the level of the transmitting and/or receiving face, making said face of the first metallic electrode wettable

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentEP3731285B1Method for producing a light-emitting and/or light-receiving device with metal optical separation grid
Publication Date: 2023.01.18 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3731285B1 patent drawingFigure 1~2
  • EP3731285B1 patent drawingFigure 3~4
  • EP3731285B1 patent drawingFigure 5~6

AI summary

Method for making a photo-emitter and/or photo-receiver device (100) with a metallic optical separation grid (140), comprising at least: - making at least one photo-emitter and/or photo-receiver component (102), in which at least one first metallic electrode (110) of the photo-emitter and/or photo-receiver component covers lateral sides of at least one semiconductor stack (104, 106, 108) of the photo-emitter and/or photo-receiver component and extends to at least one emitting and/or receiving face (112) of the photo-emitter and/or photo-receiver component; - treating at least one face of the first metallic electrode located at the level of the emitting and/or receiving face, making said face of the first metallic electrode wettable; - making the metallic optical separation grid on at least one support (142);- securing the metallic optical separation grid to the face of the first metallic electrode by brazing; - removal of the support.