Magnetic Wet Transfer of Micro LEDs for Precise Chip Alignment
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Solution Overview
Problem
The productivity of micro LED transfer methods, such as pick and place, is degraded as the size of micro LEDs decreases and the size of displays increases, leading to inefficiencies in aligning and cleaning semiconductor chips.
Innovation Solution
A chip wet transfer method using magnetic forces to align and clean semiconductor chips by employing a magnetic force generating device that adjusts magnetism based on electric signals, allowing for precise alignment and removal of misaligned chips using a magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick and place method is used to transfer micro LEDs, then the transfer method can be implemented, but productivity is degraded as the size of micro LEDs decreases and the size of display increases
Solution Approach 1:
The patent replaces the mechanical pick and place system with a magnetic field-based wet transfer system. Magnetic force generating devices create controlled magnetic fields that act on magnetically responsive micro LEDs suspended in liquid, enabling alignment and transfer without mechanical contact. This substitution allows simultaneous processing of multiple chips and maintains precision while dramatically improving productivity for large displays.
Solution Approach 2:
The patent employs a liquid medium (hydraulic principle) to suspend and transport micro LEDs during the transfer process. The liquid carrier enables uniform distribution of chips across the substrate and facilitates magnetic field penetration for precise positioning. This hydraulic approach allows parallel processing of numerous micro LEDs, overcoming the sequential limitations of mechanical methods and significantly enhancing productivity.
2Productivity
If traditional alignment and cleaning methods are used, then the process can be completed, but efficiency is reduced due to manual or mechanical operations
Solution Approach 1:
The magnetic field generation system serves multiple functions: it attracts micro LEDs to the substrate, aligns them in precise positions, and enables cleaning by removing misplaced chips through selective magnetic field application. This multi-functional approach consolidates alignment and cleaning operations into a single integrated system, improving efficiency without proportionally increasing process complexity.
Solution Approach 2:
The patent utilizes controllable magnetic field parameters (strength, direction, distribution) to dynamically adjust the transfer and alignment process. By varying magnetic field parameters, the system can attract, position, and release micro LEDs as needed, and selectively remove misplaced chips during cleaning. This parameter control enables efficient, adaptive processing that maintains high productivity while managing system complexity through programmable operations.
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
The method enhances the efficiency and accuracy of transferring micro LEDs by ensuring proper alignment and cleaning, improving productivity in semiconductor chip manufacturing.
Implementation Method 1
performing cleaning by removing semiconductor chips that are not aligned in the plurality of recesses by using a first magnetic force generating device disposed facing a lower surface of the transfer substrate
Implementation Method 2
removing, by a second magnetic force generating device, the semiconductor chips that are not aligned in the plurality of recesses from the transfer substrate by moving the semiconductor chips that are not aligned in the plurality of recesses in a first direction using a magnetic field
Data Source
AI summary
A semiconductor chip wet transfer method includes: preparing a transfer substrate that includes a plurality of recesses; supplying a liquid that includes semiconductor chips onto the plurality of recesses of the transfer substrate; aligning the semiconductor chips in the plurality of recesses by sweeping, with an align bar, an upper surface of the transfer substrate supplied with the liquid; and performing cleaning by removing semiconductor chips that are not aligned in the plurality of recesses by using a first magnetic force generating device disposed facing a lower surface of the transfer substrate.