Magnetic Semiconductor Chip Ink Assembly for Dense Micro LED Transfer
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Solution Overview
Problem
Current methods for manufacturing micro LED displays are costly and inefficient due to limitations in arranging and integrating large numbers of small micro LED chips on a substrate, with existing technologies facing challenges in precision, cost, and integration density.
Innovation Solution
A semiconductor chip integrated device manufacturing method involving a liquid-droplet-like semiconductor chip ink with chips having specific electrode configurations, where the second electrode side is more strongly attracted to a magnetic field, allowing random arrangement and electrical connection to a mounting substrate's chip joining parts, followed by forming an upper electrode with main and branch line parts for electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chip sorter method is used to transfer micro LED chips, then position confirmation and transfer accuracy are improved, but transfer rate is limited to 100-400 msec per chip and minimum chip size is limited to 100 μm
Solution Approach 1:
The patent replaces the mechanical vacuum sucking type head with a magnetic field-based sorting system. Chips with magnetic bodies are separated and transferred using magnetic field forces, enabling parallel processing of multiple chips simultaneously. This substitution of mechanical contact-based transfer with magnetic field-based transfer allows for much higher transfer rates while maintaining precision for chips smaller than 100 μm.
2Productivity
If multichip transfer device is used to transfer large number of chips at a time, then manufacturing speed is improved by several hundreds to thousands times, but sophisticated substrate processing is required and manufacturing cost increases
Solution Approach 1:
The patent extracts the magnetic body from the micro LED chip structure, making it a separate functional component. This allows the chip to be manipulated by magnetic fields during transfer and sorting, while the chip itself maintains its standard structure. The magnetic body can be added during chip fabrication and removed or deactivated after mounting, simplifying the overall process compared to sophisticated substrate processing methods.
3Manufacturing precision
If laser irradiation method is used for chip ejection and joining, then chip arrangement precision is improved, but expensive laser equipment and substrate processing are required
Solution Approach 1:
The patent replaces laser irradiation with magnetic field-based manipulation for chip ejection, transfer, and positioning. Magnetic bodies on the chips respond to magnetic field gradients, enabling precise control and positioning without requiring expensive laser equipment. The magnetic field method achieves comparable precision while significantly reducing equipment costs and eliminating the need for laser-induced substrate processing.
4Ease of operation
If magnetic film method is used for device arrangement, then chip arrangement without pre-positioning is improved, but large area magnetic films are required and substrate manufacturing cost increases
Solution Approach 1:
The patent applies magnetic fields locally at the sorting and transfer location rather than using large-area magnetic films on the substrate. The magnetic field is generated by a sorting device that can be positioned close to the chip source, creating strong localized field gradients for precise manipulation. This eliminates the need for expensive large-area magnetic film deposition on substrates while maintaining the advantage of no pre-positioning required.
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 cost-effective integration of micro LED chips on a substrate, allowing for high integration density and easy repair of inferior chips, reducing material loss and manufacturing costs while maintaining high precision and efficiency.
Implementation Method 1
a plurality of semiconductor chips, each of which has a first electrode and a second electrode on the upper surface and the lower surface and is configured such that the second electrode side is more strongly attracted to a magnetic field than the first electrode side, which are joined in random arrangement to the chip joining part
Data Source
AI summary
A liquid-droplet-like semiconductor chip ink 200 contains a liquid 50 and semiconductor chips 40, each of which has a first electrode and a second electrod on the upper surface and the lower surface and is configured such that the second electrode side is more strongly attracted to a magnetic field. The semiconductor chip ink 200 is supplied to a chip joining part on a lower electrode 420 which is formed on a mounting substrate 400, the second electrode side of the semiconductor chips 40 in the semiconductor chip ink 200 are attracted by a magnetic force by an external magnetic field so as to make contact with the chip joining part, and thereafter is electrically and mechanically joined to the chip joining part by using soldering and the like. Thereafter an upper electrode in which a plurality of branch line parts or a single branch line part are extended from a main line part so as to cover the chip joining part is formed, and the semiconductor chips 40 are connected between the lower electrode 420 and an upper electrode, whereby a semiconductor chip integrated device is manufactured.