Micro-LED Transfer Assembly With Partial Sidewall Passivation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The transfer of micro-sized semiconductor light emitting devices for large-screen displays is challenging due to low transfer precision and high risk of damage, particularly for red devices, and existing methods like pick and place and laser lift-off are inefficient for large-scale production.
Innovation Solution
A manufacturing process involving a substrate with wiring electrodes and a passivation layer covering only a portion of the semiconductor light emitting devices' side surfaces, using magnetic and electric fields for precise self-assembly, and avoiding hydrochloric acid-based solutions to prevent damage, especially for red devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pick and place method is used for transferring semiconductor light emitting devices, then transfer flexibility is improved, but transfer precision deteriorates
Solution Approach 1:
The invention divides the transfer process into two distinct stages: first, self-assembly transfer to an intermediate substrate with high precision, then pick and place to the final substrate with flexibility. This segmentation allows each stage to optimize for its specific requirement, resolving the contradiction between precision and flexibility.
Solution Approach 2:
The invention introduces an intermediate substrate as a mediator in the transfer process. The semiconductor light emitting devices are first transferred to this intermediate substrate with high precision through self-assembly, then from there to the final substrate with flexibility through pick and place. The intermediate substrate acts as a buffer that decouples the precision and flexibility requirements.
2Speed
If laser lift-off method is used for transferring semiconductor light emitting devices, then transfer speed is improved, but device damage risk increases
Solution Approach 1:
The invention extracts the high-speed transfer capability from the laser lift-off method but removes its harmful thermal effects. Instead, it uses self-assembly transfer at room temperature for the critical first transfer to the intermediate substrate, eliminating laser-induced damage while maintaining efficiency through batch processing.
Solution Approach 2:
The invention uses a disposable sacrificial layer on the intermediate substrate that facilitates easy release of the semiconductor devices. This sacrificial layer can be removed through simple chemical etching, allowing high-speed release without damaging the devices, then the devices are transferred to the final substrate.
3Productivity
If self-assembly method is used for transferring semiconductor light emitting devices, then productivity is improved, but transfer precision deteriorates
Solution Approach 1:
The invention performs preliminary patterning of the intermediate substrate with precisely positioned recesses or protrusions before the self-assembly transfer. This preliminary action creates predetermined high-precision positions that guide the self-assembly process, ensuring both high productivity through batch processing and high transfer precision through pre-defined positioning structures.
4Reliability
If passivation layer covers entire side surface of semiconductor light emitting devices, then device protection is improved, but self-assembly precision deteriorates
Solution Approach 1:
The invention applies local quality by providing different levels of passivation coverage on the semiconductor light emitting devices. The side surfaces have partial passivation that protects against damage while leaving specific regions exposed for precise positioning during self-assembly. This localized differentiation allows simultaneous achievement of protection and positioning precision.
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
Enables high-reliability, low-cost, high-efficiency transfer of large numbers of semiconductor light emitting devices to large-area substrates with reduced breakage, facilitating high-definition large-area displays.
Implementation Method 1
a passivation layer formed to cover only a portion of the side surface of the semiconductor light emitting devices
Data Source
AI summary
The present invention relates to a method for manufacturing a display device, and more particularly, to a method for manufacturing a display device using a semiconductor light emitting device having a size of several μm to several tens of μm, and to an assembly substrate used for manufacturing the display device. The present invention provides a display device, characterized in that including a substrate having a wiring electrode, a plurality of semiconductor light emitting devices electrically connected to the wiring electrode, and a passivation layer formed to cover the semiconductor light emitting device, and the passivation layer is formed to cover only a portion of a side surface of the semiconductor light emitting device.