Transferable MicroLED Array Support Structure Without Sacrificial Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for transferring microLEDs using a sacrificial layer face issues such as damage to bridge structures during wet etching, residual sacrificial layer on microLEDs, and mechanical imbalance, leading to reduced production yield and potential damage to red light-emitting epitaxial structures.
Innovation Solution
A transferable array of light emitting devices is produced by forming light emitting devices on a temporary substrate with a release layer and supporting members connected to a supporting substrate, allowing for removal of the temporary substrate without wet etching, thereby avoiding structural damage and residual issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If wet etching process is used to remove sacrificial layer, then sacrificial layer can be removed, but bridge structures are damaged and production yield decreases
Solution Approach 1:
The patent extracts and eliminates the sacrificial layer concept entirely, replacing it with a direct bonding approach where microLEDs are transferred and bonded directly to the substrate without requiring a sacrificial layer for release, thereby avoiding the need for wet etching that damages bridge structures
Solution Approach 2:
The patent introduces an adhesive layer as an intermediary between the microLED and substrate, enabling direct bonding without sacrificial layers. This adhesive mediator allows for secure attachment while avoiding the harmful wet etching process that would otherwise be needed to remove sacrificial materials
2Ease of manufacture
If sacrificial layer is coated on microLED surfaces, then microLEDs can be supported, but residual sacrificial layer remains after etching and brightness is adversely influenced
Solution Approach 1:
The patent completely removes the sacrificial layer from the manufacturing process, replacing it with direct bonding methodology. This extraction eliminates the source of residual material that would otherwise remain on microLED surfaces and degrade brightness
Solution Approach 2:
The patent employs a temporary adhesive layer that serves its purpose during transfer and bonding, then is removed or degraded without affecting the final device performance. This disposable approach replaces the problematic sacrificial layer that leaves harmful residues
3Loss of substance
If wet etching process is used, then sacrificial layer is removed, but red light-emitting epitaxial structures containing aluminum or gallium arsenide are damaged
Solution Approach 1:
The patent extracts and eliminates the wet etching process entirely by adopting direct bonding methodology. This removal of the harmful process step prevents damage to sensitive red light-emitting epitaxial structures containing aluminum or gallium arsenide
Solution Approach 2:
The patent replaces the chemical wet etching system with a mechanical/bonding-based approach. Instead of using chemical reactions to remove sacrificial layers, the process uses controlled adhesive bonding and physical transfer methods that do not expose sensitive epitaxial structures to damaging chemicals
4Productivity
If bridge structures are designed to support microLEDs after sacrificial layer removal, then microLEDs can be transferred, but bridge structures are easily broken due to sudden stress relief during wet etching
Solution Approach 1:
The patent extracts and eliminates the bridge structure concept by using direct bonding of microLEDs to the substrate. This removes the vulnerable bridge structures that would otherwise be broken during wet etching, thereby improving both transfer success rate and structural strength
Solution Approach 2:
The patent applies preliminary adhesive bonding to secure microLEDs directly to the substrate before any removal processes occur. This preliminary action eliminates the need for bridge structures and sacrificial layers, preventing stress-related failures during processing
Data Source
AI summary
A method for producing a transferable array of light emitting devices includes forming a plurality of light emitting devices on a temporary substrate, forming at least one supporting member that is directly connected to a release layer of at least one of the light emitting devices, connecting a supporting substrate only with the at least one supporting member so that the at least one supporting member extends from the release layer of the at least one of the light emitting devices to the supporting substrate and so that the light emitting devices are spaced apart from the supporting substrate, and removing the temporary substrate. The transferable array produced by the method is also disclosed.