Substrate Chuck Rotation for Bubble-Free MicroLED Self-Assembly
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Solution Overview
Problem
Current methods for manufacturing large-area displays using microLEDs face challenges in transferring and assembling semiconductor light-emitting diodes, including low transfer yields, non-specific binding, and substrate breakage due to buoyancy during self-assembly.
Innovation Solution
A substrate chuck system that includes a substrate support part, vertical moving part, electrode connection part, and rotating part to position and secure semiconductor light-emitting diodes using magnetic and electric fields, preventing bubble formation and substrate breakage by obliquely contacting the substrate with the fluid and rotating the substrate to minimize surface energy and buoyancy effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-assembly method is used to transfer microLEDs, then productivity is improved, but reliability deteriorates due to non-specific binding and low transfer yields
Solution Approach 1:
A temporary substrate is introduced as an intermediary carrier to hold microLEDs during the self-assembly process. The microLEDs are first assembled on the temporary substrate using self-assembly methods, then transferred to the final display substrate. This mediator enables high-productivity self-assembly while ensuring reliable transfer by providing a stable intermediate platform that reduces non-specific binding issues.
2Manufacturing precision
If substrate is contacted with fluid during self-assembly, then manufacturing precision is improved, but object-generated harmful factors worsen due to bubble formation
Solution Approach 1:
The temporary substrate is pre-treated with a hydrophobic coating before the self-assembly process. This preliminary action creates a surface that repels water and prevents bubble adhesion. When the substrate is contacted with fluid during microLED assembly, bubbles form but do not adhere to the hydrophobic surface, allowing them to be easily removed and preventing positioning errors.
3Ease of operation
If substrate is separated from fluid after self-assembly, then ease of operation is improved, but object-generated harmful factors worsen due to microLED separation
Solution Approach 1:
The temporary substrate acts as a mediator that maintains microLED attachment during the critical separation process. After self-assembly in fluid, the temporary substrate with attached microLEDs is carefully separated from the fluid environment. The mediator substrate provides mechanical support and maintains the assembled structure, preventing microLED detachment even when the fluid environment is removed.
4Productivity
If substrate is subjected to buoyancy during self-assembly, then ease of operation worsens due to substrate breakage, but productivity is improved
Solution Approach 1:
The temporary substrate is designed with increased rigidity and structural support to counteract the buoyancy forces acting on it during self-assembly. The mediator substrate provides mechanical strength that balances the upward buoyant force from the fluid, preventing substrate deformation and breakage while allowing high-speed automated assembly operations to proceed.
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-yield, low-cost, and efficient assembly of microLEDs on large-area substrates by preventing non-specific binding and substrate breakage, allowing for quick and precise transfer of semiconductor light-emitting diodes while maintaining substrate integrity.
Implementation Method 1
an electrode connection part for applying a power to the assembly electrode to generate an electric field so that the semiconductor light-emitting diodes are placed at a predetermined position of the substrate
Implementation Method 2
capable of preventing the substrate from being broken due to buoyancy applied to the substrate during self-assembly
Data Source
AI summary
Discussed is a substrate chuck including: a substrate support part for supporting a substrate having an assembly electrode; a vertical moving part which moves the substrate so that one surface of the substrate comes in contact with a fluid in a state in which the substrate is supported by the substrate support; an electrode connection part for applying power to the assembly electrode to generate an electric field so that semiconductor light-emitting diodes are placed at the predetermined positions of the substrate in a process of moving the semiconductor light-emitting diodes by a position change of at least one magnet; and a rotating part for rotating the substrate support part around a rotating shaft so that the substrate is placed in an upward or downward direction, wherein the rotating shaft is spaced apart from a center of the substrate support part at a predetermined distance.