Wet Micro-Chip Alignment for Large-Area Micro-LED Transfer
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Solution Overview
Problem
Conventional pick and place (PNP) methods for transferring micro-LED chips are limited by speed and require tiling, leading to dark spots and increased repair needs as display areas increase, especially for large area transfers.
Innovation Solution
A wet alignment method using a solution to disperse micro-LEDs, spraying the solution onto a transfer substrate with pre-formed grooves, and using an absorber to align and transfer the chips, allowing for high-speed, repair-free transfer of micro-LEDs across large areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional pick and place method is used for transferring micro-LED chips, then transfer precision can be maintained, but transfer speed decreases and tiling is required for large areas
Solution Approach 1:
The patent introduces a liquid suspension as an intermediary medium to carry micro-LED chips to the substrate. The suspension allows chips to be transported and deposited in a controlled manner, achieving both high-speed transfer and precise alignment without requiring conventional pick-and-place mechanisms. The liquid medium enables simultaneous transport of multiple chips across large areas.
Solution Approach 2:
The patent employs liquid flow (hydraulic principle) to transport micro-LED chips suspended in liquid from a source to a target substrate. The liquid flow enables high-speed, parallel transport of numerous chips simultaneously, eliminating the sequential nature of conventional mechanical pick-and-place methods and achieving both speed and precision.
2Area of stationary object
If display area is increased using conventional PNP method, then larger display can be achieved, but dark spots appear and repair needs increase
Solution Approach 1:
The liquid suspension system enables micro-LED chips to self-align and self-assemble on the substrate through the flow dynamics and interaction with the substrate surface. This self-organizing behavior ensures uniform distribution and proper positioning across large display areas, eliminating dark spots and reducing defects without requiring post-transfer repair operations.
3Manufacturing precision
If micro-LED size is decreased to improve display quality, then display resolution improves, but transfer yield rate decreases with conventional PNP method
Solution Approach 1:
The patent changes the physical state and handling parameters of micro-LED chips by suspending them in liquid rather than manipulating them as discrete solid objects. This parameter change enables efficient handling of extremely small chips that would be difficult or impossible to manipulate with conventional mechanical pick-and-place tools, maintaining both high resolution and high transfer yield.
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 method enhances transfer speed and reduces the need for repairs by aligning micro-LEDs efficiently, eliminating dark spots and accommodating a larger number of chips without the limitations of conventional PNP methods.
Implementation Method 1
a liquid suspension of emissive elements. The suspension is flowed across the emissive substrate
Implementation Method 2
The suspension is flowed across the emissive substrate and the emissive elements are captured in the wells
Implementation Method 3
using an absorber to align and transfer the chips
Data Source
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AI summary
A wet alignment method for a micro-semiconductor chip and a display transfer structure are provided. The wet alignment method for a micro-semiconductor chip includes: supplying a liquid to a transfer substrate including a plurality of grooves; supplying the micro-semiconductor chip onto the transfer substrate; scanning the transfer substrate by using an absorber capable of absorbing the liquid. According to the wet alignment method, the micro-semiconductor chip may be transferred onto a large area.