Transparent Electrostatic Transfer Head for LED Alignment
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Solution Overview
Problem
Current methods for transferring semiconductor light-emitting devices face challenges such as difficult alignment, high manufacturing costs, low yield rates, and inability to accurately adjust for horizontality and step heights, especially when dealing with micro-devices and flexible displays.
Innovation Solution
A transfer head with a simple structure using a transparent substrate and electrode unit to generate electrostatic forces for precise alignment and pickup of semiconductor light-emitting devices, allowing for high-yield, cost-effective, and flexible transfer of micro-devices, including those on flexible substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a PDMS stamp type transfer head or electrostatic gripper is used, then the transfer of semiconductor light-emitting devices can be performed, but alignment becomes difficult
Solution Approach 1:
The patent introduces a transparent substrate that allows optical observation from the rear side, adding a visual dimension to the transfer process. This enables alignment verification through the substrate itself, transforming the alignment process from a blind mechanical operation to an optically-guided process, thereby resolving the contradiction between transfer capability and alignment precision
Solution Approach 2:
The transparent substrate acts as an intermediary element that mediates between the transfer head and the semiconductor devices. It provides a window for optical alignment while maintaining the electrostatic gripping function, allowing simultaneous achievement of transfer capability and alignment precision through this intermediate transparent medium
2Manufacturing precision
If multi-axis actuators with sensors are used for horizontality adjustment, then alignment between wafers can be performed, but the input values from sensors are inaccurate and accurate horizontality cannot be adjusted
Solution Approach 1:
The patent replaces the sensor-based mechanical measurement system with an optical observation system. Instead of relying on inaccurate sensor readings for horizontality adjustment, the transparent substrate enables direct visual verification of device positioning and wafer alignment, substituting mechanical-sensor measurement with optical-field measurement that provides accurate visual feedback
Solution Approach 2:
The transparent substrate enables self-verification of alignment and horizontality through optical observation. The system allows operators to directly see whether devices are properly positioned and whether wafers are horizontally aligned, eliminating dependence on external sensors and enabling self-correcting alignment through visual feedback
3Productivity
If conventional transfer methods are used, then transfer can be performed, but manufacturing cost is high and yield rate is low
Solution Approach 1:
The patent employs a simple transparent substrate that can be easily manufactured and replaced if needed. This disposable or easily replaceable substrate eliminates the need for expensive, complex alignment mechanisms, thereby reducing manufacturing cost while maintaining high transfer yield through improved alignment capability
Solution Approach 2:
The patent extracts the alignment function from complex mechanical systems and sensors, isolating it into a simple optical observation capability provided by the transparent substrate. This extraction simplifies the overall system, reducing manufacturing cost while preserving the critical alignment function that determines yield rate
4Manufacturing precision
If complex multi-axis rotation and transfer mechanisms are used, then alignment can be attempted, but it is unable to adjust accurate horizontality and difficult to pick up micro-devices in cases of slope or height difference
Solution Approach 1:
The patent extracts the alignment verification function from complex multi-axis mechanisms and places it in the transparent substrate. This allows simple pick-up mechanisms to achieve precise alignment through visual feedback, separating the alignment verification function from the mechanical positioning function and eliminating the need for complex aligned mechanisms
Solution Approach 2:
The transparent substrate enables the transfer system to self-verify alignment and horizontality through optical observation. Operators can directly see positioning accuracy and make simple adjustments without complex feedback control systems, allowing the system to self-correct alignment issues through visual feedback rather than requiring complex automated mechanisms
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 solution enables precise alignment and high-yield transfer of semiconductor light-emitting devices with reduced manufacturing costs, facilitating the use of flexible displays and improving the transfer of micro-devices by providing a high degree of freedom and accurate alignment without the need for sensors.
Implementation Method 1
an electrode unit disposed on the base substrate to generate an electrostatic force by electrifying an undoped semiconductor layer of the semiconductor light-emitting device
Data Source
AI summary
The present invention relates to a display device and, more particularly, to a transfer head for a semiconductor light-emitting device applied to the display device and a method for transferring a semiconductor light-emitting device. The transfer head for a semiconductor light-emitting device, according to the present invention, comprises: a base substrate; and an electrode unit disposed on the base substrate to generate an electrostatic force by charging an un-doped semiconductor layer of the semiconductor light-emitting device with electric charges, wherein the base substrate and the electrode unit are formed of light-transmitting materials so that at least a part of the semiconductor light-emitting device is viewable through the base substrate and the electrode unit in sequence.