Micro LED Mass Transfer via Magnetic Pole Electroplating
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Solution Overview
Problem
The challenge lies in efficiently transferring a large number of micro light emitting diode (micro LED) chips to a display substrate in batches with high efficiency and low cost, due to their small size and the need for millions of sub-pixels, which is a key difficulty in mass transfer technology.
Innovation Solution
A mass transfer method involving bonding micro LED chips on a sapphire substrate to a transfer substrate, peeling off the sapphire substrate to generate magnetic poles, placing the chips in a dispersion liquid, and using a magnetic field to position them onto soldering areas on a display substrate, where they are fixed using a thermocuring process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional LED structures are miniaturized and matrixed to create micro LED chips, then display resolution and brightness are improved, but the difficulty of mass transfer to display substrate increases significantly
Solution Approach 1:
A transfer substrate is introduced as an intermediary carrier to temporarily hold the micro LED chips during the transfer process. The chips are first bonded to the transfer substrate, then the original sapphire substrate is removed, and finally the chips are transferred to the display substrate. This intermediary approach simplifies the complex direct transfer from sapphire to display substrate.
Solution Approach 2:
Magnetic fields are used to replace traditional mechanical transfer methods. Magnetic poles are generated at corresponding positions of the micro LED chips through magnetic pole electroplating, and a magnetic field force is applied to position the chips onto the display substrate, eliminating the need for complex mechanical handling of individual chips.
2Productivity
If a large number of micro LED chips are transferred in batches, then transfer efficiency is improved, but the cost and technical difficulty increase
Solution Approach 1:
Multiple micro LED chips are processed and transferred simultaneously in batch form rather than individually. The entire array of chips remains on the transfer substrate during the process, allowing parallel operations for bonding, substrate removal, and transfer, which significantly improves productivity while controlling costs.
Solution Approach 2:
The magnetic properties of the chips are changed by electroplating magnetic poles, enabling the use of magnetic field forces for transfer. This parameter change allows for simple and cost-effective batch transfer using magnetic fields rather than complex mechanical or chemical methods.
3Measurement precision
If magnetic pole electroplating is performed on micro LED chips, then precise positioning capability is improved, but the process complexity increases
Solution Approach 1:
Magnetic poles are electroplated on the micro LED chips in advance during the transfer substrate processing stage, before the chips are separated and transferred. This preliminary action ensures that the positioning capability is already built into the chips, simplifying the subsequent transfer process.
Solution Approach 2:
The transfer substrate serves as an intermediary that facilitates the magnetic pole electroplating process. The chips are processed on the transfer substrate, which provides a stable platform for electroplating, and then the substrate is removed without affecting the magnetic poles already formed on the chips.
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 method enables efficient and selective transfer of micro LED chips to the display substrate, improving transfer efficiency and reducing costs by utilizing magnetic fields and surface energy control layers to accurately position and fix the chips.
Implementation Method 1
placing the micro light emitting diode chips, which are dispersed in the dispersion liquid, in the soldering areas under an action of a magnetic field force
Implementation Method 2
performing magnetic pole electroplating on the micro light emitting diode chips obtained by peeling off the sapphire substrate to enable corresponding magnetic poles to be generated at corresponding positions of the micro light emitting diode chips
Implementation Method 3
fixing the micro light emitting diode chips dispersed using a thermocuring process
Data Source
AI summary
The disclosure provides a mass transfer method and device for micro light emitting diode chips. The method includes the following steps: performing magnetic pole electroplating on the micro light emitting diode chips obtained by peeling off the sapphire substrate to enable corresponding magnetic poles to be generated at corresponding positions of the micro light emitting diode chips; peeling off the transfer substrate, and placing the micro light emitting diode chips obtained by peeling off the transfer substrate in a dispersion liquid to form a solution in which micro light emitting diode chips are dispersed; and the display substrate picks up the micro light emitting diode chips dispersed under the action of the magnetic field force.