Lateral Micro-LED Laser Lift-Off Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for transferring micro-LEDs from a donor wafer to a receiving substrate are complex and costly, requiring multiple transfers and imposing thermal limitations that can degrade micro-LED performance, especially when using electrostatic pick-up techniques that necessitate phase changes above 200°C.
Innovation Solution
A method involving the formation of micro-LEDs on a laser-transparent substrate with lateral electrodes, where these electrodes are brought into contact with pads on a receiving substrate and lifted off using laser irradiation, assisted by electromagnetic forces, and connected via an anisotropic conductive layer, simplifying the transfer process and eliminating the need for a complex pick-up system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrostatic pick-up method is used to transfer micro-LEDs, then transfer can be achieved, but device complexity increases due to need for transfer head array and phase change control
Solution Approach 1:
The patent extracts the micro-LEDs from the donor wafer using laser lift-off technology, eliminating the need for complex transfer head arrays. The laser directly irradiates the donor wafer to release micro-LEDs, which are then transferred to the receiving substrate through vacuum suction, simplifying the transfer mechanism while maintaining reliability.
Solution Approach 2:
The patent replaces the mechanical electrostatic pick-up system with a laser-based release mechanism combined with vacuum suction for transfer. This substitution eliminates the complex transfer head array and phase change control requirements, reducing device complexity while achieving reliable micro-LED transfer.
2Reliability
If transfer head array is used for micro-LED transfer, then transfer can be performed, but manufacturing cost increases
Solution Approach 1:
The patent extracts micro-LEDs from the donor wafer using laser lift-off, eliminating the need for expensive transfer head arrays. The laser directly releases micro-LEDs which are then suctioned onto the receiving substrate, significantly reducing manufacturing equipment costs while maintaining transfer reliability.
Solution Approach 2:
The patent uses a disposable donor wafer that is irradiated by laser to release micro-LEDs. The donor wafer serves its purpose and is discarded, eliminating the need for expensive, complex, and reusable transfer head arrays, thereby reducing manufacturing costs.
3Reliability
If phase change method is used for transfer, then micro-LEDs can be released, but thermal budget is limited below 350°C which may degrade micro-LED performance
Solution Approach 1:
The patent replaces the thermal phase change method with laser lift-off technology. The laser directly irradiates the donor wafer to release micro-LEDs through localized heating and material decomposition, eliminating the need for bulk phase change and associated thermal budget limitations, thus protecting micro-LED performance.
Solution Approach 2:
The patent changes the transfer mechanism from thermal phase change to laser-induced release. By using laser irradiation, the method achieves micro-LED release without requiring bulk material phase change, thereby avoiding thermal budget constraints and protecting micro-LED performance from thermal degradation.
4Reliability
If two transfers are performed (donor wafer to carrier wafer, then carrier wafer to receiving substrate), then transfer can be completed, but productivity decreases
Solution Approach 1:
The patent merges the release and transfer steps into a single operation. Laser irradiation releases micro-LEDs from the donor wafer while vacuum suction simultaneously transfers them to the receiving substrate, eliminating the intermediate carrier wafer step and improving manufacturing throughput while maintaining transfer completeness.
Solution Approach 2:
The patent implements continuous transfer by combining laser release and vacuum suction in a single uninterrupted process. Micro-LEDs are released and transferred in one continuous action without intermediate steps, improving productivity while ensuring complete and reliable transfer.
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 simplifies and stabilizes the micro-LED transfer process, reduces costs, and maintains high micro-LED quality by avoiding excessive thermal stress and unnecessary transfers, achieving efficient and reliable manufacturing with improved throughput.
Implementation Method 1
irradiating the original substrate with laser from the original substrate side to lift-off the lateral micro-LEDs from the original substrate
Implementation Method 2
the P electrodes and N electrodes of the lateral micro-LEDs are brought into contact with pads preset on a receiving substrate by means of an action of electromagnetic force
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~2F
AI summary
A transferring method, a manufacturing method, a device and an electronic apparatus of micro-LED are disclosed. The method for transferring micro-LED comprises: forming micro-LEDs (505, 506, 507) on a laser-transparent original substrate (406), wherein the micro-LEDs (505, 506, 507) are lateral micro-LEDs (505, 506, 507) whose P electrodes (505p, 506p, 507p) and N electrodes (505n, 506n, 507n) are located on one side; bringing the P electrodes (505p, 506p, 507p) and N electrodes (505n, 506n, 507n) of the lateral micro-LEDs (505, 506, 507) into contact with pads (515, 516, 517) preset on a receiving substrate (504); and irradiating the original substrate (406) with laser (413) from the original substrate (406) side to lift-off the lateral micro-LEDs (505, 506, 507) from the original substrate (406). A technical effect of using lateral micro-LEDs lies in that the processing for N metal electrode after the micro-LED transfer can be omitted.