Assembly Substrate Cell Structure for Micro-LED Transfer
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Solution Overview
Problem
The transfer of semiconductor light-emitting devices (micro-LEDs) to a final substrate is challenging due to difficulties in positioning and transferring millions of LEDs efficiently, particularly in large display applications, where existing methods like pick and place and laser lift-off have low success rates and yield issues.
Innovation Solution
An assembly substrate is designed with protrusions and a functional layer having a lower contact force than the cell material, combined with the use of electric and magnetic fields to guide and place semiconductor light-emitting devices at predetermined positions, reducing contact force and improving transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If self-assembly technique is used to transfer semiconductor light-emitting devices, then large area display manufacturing becomes feasible, but transfer rate and positioning precision are insufficient
Solution Approach 1:
The assembly substrate is divided into multiple cells, each capable of independently holding and transferring semiconductor light-emitting devices. This segmentation allows parallel processing across multiple cells, significantly increasing the overall transfer rate while maintaining precise positioning control in each cell.
Solution Approach 2:
The patent replaces traditional mechanical pick-and-place methods with a self-assembly technique utilizing electric fields and magnetic fields. Semiconductor light-emitting devices with magnetic materials are guided by magnetic fields to predetermined positions on the assembly substrate, eliminating mechanical contact and enabling high-speed, high-precision transfer across large areas.
2Ease of manufacture
If conventional transfer methods are used, then manufacturing process is simple, but yield and positioning precision are low
Solution Approach 1:
The patent introduces magnetic materials as an intermediary between the semiconductor light-emitting devices and the magnetic field generation system. These magnetic materials enable precise positioning and orientation of the devices during transfer by responding to externally applied magnetic fields, achieving high positioning precision without complex mechanical positioning systems.
Solution Approach 2:
The patent utilizes changes in magnetic field parameters (strength, direction, distribution) to control the positioning and orientation of semiconductor light-emitting devices during transfer. By dynamically adjusting magnetic field parameters, precise positioning is achieved while maintaining a relatively simple manufacturing process compared to mechanical alternatives.
3Stability of the object's composition
If assembly substrate with high contact force is used, then device stability during assembly is improved, but transfer efficiency to final substrate decreases
Solution Approach 1:
The patent employs dynamic control of magnetic fields to adjust the effective contact force between semiconductor light-emitting devices and the assembly substrate. During assembly, magnetic fields provide strong holding force for stability; during transfer, magnetic fields are adjusted to reduce contact force, enabling efficient release and transfer to the final substrate without mechanical contact.
Solution Approach 2:
The patent replaces mechanical contact forces with magnetic field-based holding and release mechanisms. This substitution allows independent control of holding strength and release ease, achieving both high assembly stability and high transfer efficiency without the trade-off inherent in mechanical systems where stronger contact improves stability but hinders release.
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 proposed method enhances the transfer rate of semiconductor light-emitting devices by minimizing contact force and energy at the assembly substrate interface, thereby increasing the yield and efficiency of large-area display manufacturing.
Implementation Method 1
placing semiconductor light-emitting devices to predetermined positions of the assembly substrate using an electric field and a magnetic field
Implementation Method 2
placing semiconductor light-emitting devices to predetermined positions of the assembly substrate using an electric field and a magnetic field
Implementation Method 3
A protrusion part protrudes inward from at least one of inner surfaces of each of the cells... improve a transfer rate in a process of transferring semiconductor light-emitting devices seated on an assembly substrate
Data Source
AI summary
Discussed is an assembly substrate used in a display manufacturing method for placing semiconductor light-emitting devices to predetermined positions thereof using an electric field and a magnetic field, the assembly substrate including a base part; a plurality of assembly electrodes extending in one direction and disposed in parallel on the base part; a dielectric layer disposed on the base part to cover the plurality of assembly electrodes; and partition walls disposed on the dielectric layer and defining cells at predetermined intervals along the one direction of the plurality of assembly electrodes so as to overlap portions of the plurality of assembly electrodes, and the semiconductor light-emitting devices being placed into the cells, respectively, wherein a protrusion part protrudes inward from at least one of inner surfaces of each of the cells.