Micro Device Transfer via Fixing Layer Patterning
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Solution Overview
Problem
The existing methods for manufacturing micro LED arrays face challenges in reducing manufacturing costs and improving yield, particularly in the transfer process of micro devices, which affects the efficiency and reliability of the micro LED array.
Innovation Solution
A method involving a carrier substrate with a fixing layer and a transfer device that uses electrostatic, magnetic, or elastic forces to pick up and transfer micro devices to a receiving substrate, allowing for selective exposure and transfer without direct contact, thereby reducing manufacturing costs and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional packaging technology such as flip chip bonding is used to electrically connect micro LEDs and array substrate, then electrical connection is achieved, but manufacturing cost increases and manufacturing complexity increases
Solution Approach 1:
The patent introduces a transfer substrate as an intermediary carrier that temporarily holds micro LEDs during the transfer process. This mediator enables indirect transfer of micro LEDs to the array substrate, avoiding direct complex bonding operations and reducing manufacturing difficulty while maintaining connection reliability
Solution Approach 2:
The patent replaces traditional mechanical flip chip bonding with a transfer-based approach using suction cups for pickup and placement. This substitution simplifies the mechanical complexity of the bonding process while achieving reliable electrical connections through the transfer substrate interface
2Productivity
If micro LEDs are transferred using direct contact methods, then transfer is achieved, but contamination occurs and yield decreases
Solution Approach 1:
The transfer substrate serves as a clean intermediary that prevents direct contact between the pickup tool and the micro LED. This mediator minimizes contamination risk during transfer while maintaining high yield through controlled transfer conditions
Solution Approach 2:
The patent implements a controlled clean room environment and uses a clean transfer substrate to create an inert transfer environment. This prevents contamination of micro LEDs during the transfer process while maintaining high transfer yield
3Manufacturing precision
If selective exposure of micro devices is not implemented, then transfer process is simplified, but alignment precision decreases and manufacturing precision worsens
Solution Approach 1:
The patent applies a fixing layer to the transfer substrate before transferring micro LEDs. This preliminary action secures the micro LEDs in their correct positions, ensuring precise alignment during transfer while the systematic process manages the added complexity
Solution Approach 2:
The transfer substrate with fixing layer acts as an intermediary that pre-positions micro LEDs with high precision before final placement on the array substrate. This mediator enables precise alignment control while the automated transfer system manages process complexity
4Productivity
If multiple micro LEDs are transferred in one operation, then productivity increases, but alignment precision may decrease
Solution Approach 1:
The patent divides the transfer process into discrete operations where groups of micro LEDs are transferred in batches. This segmentation allows maintaining precision for each batch while achieving high overall productivity through multiple efficient transfer cycles
Solution Approach 2:
The transfer substrate serves as a mediator that holds multiple micro LEDs in precise positions simultaneously. This intermediary enables batch transfer operations that maintain alignment precision while significantly improving transfer efficiency compared to individual transfers
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 transfer of micro devices with reduced manufacturing costs and improved yield, enhancing the characteristics of micro LED arrays by minimizing alignment issues and contamination, and allowing for precise patterning of the fixing layer to expose only the necessary micro devices for transfer.
Implementation Method 1
the pick-up surface of the transfer device has a metal layer connected to an external circuit, thereby generating an electrostatic force on the metal layer to pick up the exposed micro devices
Implementation Method 2
the pick-up surface of the transfer device has a metal layer connected to an external circuit, thereby generating a magnetic force on the conductive magnetic layer to pick up the exposed micro devices
Implementation Method 3
the pick-up surface of the transfer device has an elastic adhesive layer, and the transfer device picks up the exposed micro devices by using the elastic adhesive layer
Data Source
AI summary
A method for transferring micro devices is provided. The method includes the following operations: providing a carrier substrate and forming micro devices on the carrier substrate; forming a fixing layer on the carrier substrate, in which the fixing layer is at least in contact with bottom parts of the micro devices; patterning the fixing layer to selectively expose a portion of the micro devices; providing a transfer device correspondingly located on the carrier substrate, and picking up the exposed micro devices by the transfer device; and providing a receiving substrate and transferring the exposed micro devices to the receiving substrate.