Micro-LED Carrier Substrate for Pre-Mount Electrical Inspection
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Solution Overview
Problem
The inspection of electrical qualities of micro LEDs is difficult due to their small size, making it challenging to determine the electrical properties before mounting on a substrate, which affects the yield rate and efficiency of the manufacturing process.
Innovation Solution
A method for manufacturing a carrier substrate that allows for a current flow inspection of micro LEDs before mounting, involving the formation of conductive paths and feeding pads, transfer to a carrier substrate, and a subsequent etching process to divide and inspect the LEDs, ensuring electrical qualities are determined before final mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If micro LEDs are manufactured using deposition method through wafers, then the manufacturing precision and size control are improved, but the inspection of electrical qualities becomes very difficult
Solution Approach 1:
The patent introduces a carrier substrate as an intermediary component that holds multiple micro LEDs during the inspection process. This carrier substrate provides a stable platform with conductive paths that enable electrical testing of micro LEDs without requiring individual handling, thus solving the inspection difficulty while maintaining the precision benefits of wafer-based manufacturing.
Solution Approach 2:
The patent segments the inspection process by first inspecting multiple micro LEDs collectively on the carrier substrate, then selectively picking and placing only the qualified units. This segmentation allows electrical quality inspection to be performed on groups rather than individuals, making the inspection process feasible while maintaining high manufacturing precision.
2Reliability
If individual micro LED inspection is performed before mounting, then the yield rate is improved, but the manufacturing time and process complexity increase
Solution Approach 1:
The patent merges multiple micro LEDs onto a single carrier substrate for collective inspection. By combining multiple units that would otherwise require separate inspection processes, the total inspection time is reduced while maintaining quality control, thus improving yield rate without proportionally increasing manufacturing time.
Solution Approach 2:
The patent performs preliminary electrical quality inspection on micro LEDs while they are still mounted on the carrier substrate, before the final picking and placing process. This preliminary action allows defective units to be identified and excluded early, improving the overall yield rate without adding significant time to the manufacturing process.
3Manufacturing precision
If micro LEDs of several tens of μm are transferred to substrate with high precision, then the display resolution is improved, but the transfer process complexity and cost increase
Solution Approach 1:
The carrier substrate serves as an intermediary platform that simplifies the transfer process. Micro LEDs are first mounted on the carrier substrate in an array, inspected collectively, and then transferred to the final display substrate as a group. This intermediary step reduces the complexity of individual handling and transfer operations while maintaining high transfer precision.
Solution Approach 2:
The transfer process is segmented into two stages: first, mounting multiple micro LEDs on the carrier substrate in an organized array; second, transferring the qualified units from the carrier to the final substrate. This segmentation allows for simplified individual operations within each stage while achieving high overall transfer precision.
Data Source
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AI summary
Various embodiments comprise: a substrate; a plurality of unit electric elements arranged on the substrate at regular intervals; and at least one conductive path electrically connected to each of the plurality of unit electric elements nearby and having an energized inspection area formed at an end thereof. It is possible to determine whether each of the plurality of unit electric elements is electrically good or defective by using an energized inspection area of the conductive path. Other various embodiments may be possible.