Maskless Parallel Transfer of Micro-Devices via Photochemical Adhesive Release
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Solution Overview
Problem
Manufacturing microLED panels with micron-scale LEDs based on III-V semiconductor technology faces challenges such as technical and manufacturing hurdles when depositing and growing LEDs directly on a final display substrate, especially for curved or bendable displays, and existing transfer methods like pick-and-place machines have low throughput.
Innovation Solution
A system and method for surface mounting micro-devices involve a transfer body with an adhesive layer, actuators for relative motion, and a digital mirror device for maskless exposure of the adhesive layer to selectively detach micro-devices from the donor substrate and transfer them to a destination substrate, allowing for high precision and increased throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick-and-place machines are used to transfer micro-devices, then individual devices can be placed on the substrate, but the throughput is low and manufacturing time is excessive
Solution Approach 1:
The adhesive layer is divided into multiple independently controllable regions, allowing selective release of different groups of micro-devices simultaneously. This segmentation enables parallel processing of multiple devices, dramatically increasing throughput compared to sequential pick-and-place methods
Solution Approach 2:
Multiple micro-devices are transferred and placed on the substrate simultaneously in a single operation rather than individually. The system combines the transfer and placement functions into one unified process, achieving high-volume transfer in parallel
2Ease of manufacture
If micro-devices are fabricated directly on the final display substrate, then the process is simplified, but it is difficult to manufacture curved or bendable displays and III-V semiconductor microLEDs face technical hurdles
Solution Approach 1:
A transfer substrate is introduced as an intermediary between the fabrication process and the final display substrate. Micro-devices are fabricated on the transfer substrate where conditions are optimal for growth, then transferred to the final substrate which can be curved or flexible. This intermediary enables both easy fabrication and substrate versatility
Solution Approach 2:
The fabrication process is segmented into two independent stages: device fabrication on a specialized transfer substrate, and subsequent transfer to the final display substrate. This separation allows each stage to be optimized independently - the transfer substrate for fabrication ease and the final substrate for flexibility and display requirements
3Productivity
If a continuous adhesive layer is used to attach micro-devices, then all devices can be transferred at once, but it is difficult to selectively release specific regions without a mask
Solution Approach 1:
The adhesive layer has different properties in different regions - some regions are photo-active and can be selectively released by light exposure, while other regions remain adhesive. This local differentiation of adhesive properties enables selective release of specific micro-device regions without requiring physical masks, maintaining high transfer efficiency while providing precise release control
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 approach enables efficient transfer of micro-devices with high precision and increased yield, reducing manufacturing time and cost, and facilitates the production of flexible and multi-color displays by allowing micro-devices to be fabricated at a higher spatial density than needed for the destination substrate.
Implementation Method 1
illumination system configured to selectively and masklessly expose regions of the adhesive layer on the transfer body... cause the illumination system to selectively expose one or more portions of the adhesive layer to create one or more neutralized portions
Data Source
AI summary
An apparatus for positioning micro-devices on a destination substrate includes a first support to hold a destination substrate, a second support to provide or hold a transfer body having a surface to receive an adhesive layer, a light source to generate a light beam, a mirror configured to adjustably position the light beam on the adhesive layer on the transfer body, and a controller. The controller is configured to cause the light source to generate the light beam and adjust the mirror to position the light beam on the adhesive layer so as to selectively expose one or more portions of the adhesive layer to create one or more neutralized portions. The transfer body and the destination substrate are moved away from each other and one or more micro-devices corresponding to the one or more neutralized portions of the adhesive layer remain on the destination substrate.