MicroLED Self-Assembly With Vacuum Flattening for Warpage Control
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Solution Overview
Problem
The challenge lies in efficiently transferring millions of microLEDs to a large-area substrate for display manufacturing, as existing methods face difficulties in achieving high transfer yields and are hindered by substrate warpage and assembly deviations.
Innovation Solution
A self-assembly device and method that utilize a combination of magnetic and electric fields to guide microLEDs onto a substrate within a fluid chamber, while a vacuum forming part corrects substrate warpage and maintains a predetermined distance between the magnetic chuck and the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-assembly method is used to transfer microLEDs, then transfer efficiency is improved, but assembly precision deteriorates due to substrate warpage
Solution Approach 1:
The patent applies preliminary action by flattening the substrate before the self-assembly process begins. The flattening unit pre-processes the substrate to eliminate warpage, ensuring that when microLEDs are transferred via self-assembly, the assembly precision is not compromised. This resolves the contradiction by preparing the substrate in advance to maintain precision while enabling efficient bulk transfer.
Solution Approach 2:
The patent introduces a flattening unit as an intermediary component between the substrate and the self-assembly process. This intermediary device actively corrects substrate warpage, creating a flat surface that enables both high transfer efficiency and high assembly precision. The flattening unit acts as a mediator that eliminates the harmful effect of warpage without interfering with the self-assembly mechanism.
2Manufacturing precision
If magnetic chuck is positioned close to substrate, then assembly precision is improved, but substrate damage increases due to warpage
Solution Approach 1:
The patent applies preliminary action by flattening the substrate before positioning the magnetic chuck close to it. The flattening unit eliminates warpage in advance, so when the magnetic chuck is positioned close to the substrate for precise assembly, there is no warpage-induced damage. This resolves the contradiction by preparing the substrate beforehand to enable close positioning without harmful effects.
Solution Approach 2:
The flattening unit serves as an intermediary that eliminates substrate warpage, allowing the magnetic chuck to be positioned close to the substrate without causing damage. By mediating the substrate condition, the flattening unit enables the magnetic chuck to operate at optimal distance for precision while preventing the harmful effects of warpage.
3Manufacturing precision
If conventional transfer methods are used, then assembly precision is maintained, but transfer efficiency deteriorates for large-scale displays
Solution Approach 1:
The patent merges two previously separate processes into one integrated system: substrate flattening and microLED self-assembly. The flattening unit and self-assembly unit work together in sequence, combining the precision-enabling flattening step with the efficiency-enabling self-assembly step. This merged system achieves both high assembly precision and high transfer efficiency simultaneously, resolving the contradiction between precision and productivity.
Solution Approach 2:
The flattening unit acts as an intermediary that enables the self-assembly process to achieve both precision and efficiency. By preparing the substrate in advance, it allows the self-assembly unit to transfer millions of microLEDs efficiently while maintaining high precision, something that conventional transfer methods could not achieve at scale.
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 approach enables efficient and high-speed transfer of microLEDs onto large-area substrates with improved assembly precision and reduced substrate damage, facilitating the production of large-screen display devices.
Implementation Method 1
a magnetic chuck disposed above the assembly chamber and configured to apply magnetic force, while moving in a horizontal direction, to induce movement of the semiconductor light emitting diodes within the assembly chamber
Implementation Method 2
a vacuum forming part configured to correct a bending (warpage) phenomenon of the assembly substrate by using vacuum pressure between the plurality of magnets
Data Source
AI summary
A semiconductor light emitting diode self-assembling device according to the present invention comprises: an assembly chamber in which fluid and semiconductor light emitting diodes are received; a magnetic chuck disposed above the assembly chamber and applying, while moving in a horizontal direction, a magnetic force thereto so as to induce movement of the semiconductor light emitting diodes in the assembly chamber; a substrate chuck for placing an assembly substrate, on which the semiconductor light emitting diodes in the assembly chamber are seated, between the assembly chamber and the magnetic chuck and supporting the assembly substrate; and a control part for controlling the driving of the magnetic chuck and the substrate chuck, wherein the magnetic chuck includes: a magnetic force forming part including a plurality of magnets; and a vacuum forming part for correcting a bending phenomenon of the assembly substrate by using vacuum pressure between the plurality of magnets so as to maintain a predetermined interval between one side of the magnetic chuck and the assembly substrate.