Methods of parallel transfer of micro-devices using mask layer
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Solution Overview
Problem
The manufacturing of microLED panels using III-V semiconductor technology faces challenges such as technical hurdles in depositing and growing microLEDs directly on a final display substrate, and difficulties in producing curved or bendable displays, with existing transfer methods like pick-and-place being inefficient for high throughput.
Innovation Solution
A method involving a selectively treated adhesive layer on a donor substrate, where illumination is used to neutralize specific portions of the adhesive, allowing for precise transfer of micro-devices to a destination substrate, enabling higher spatial density, flexible, and cost-effective manufacturing of micro-devices, including microLEDs for multi-color displays and flexible displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick-and-place method is used for transferring micro-devices, then individual device placement is achieved, but throughput is low and manufacturing time is long
Solution Approach 1:
The patent merges multiple individual transfer operations into a single parallel transfer operation. Multiple micro-devices are simultaneously transferred from the donor substrate to the destination substrate in one step, rather than transferring them individually. This is achieved by using a transfer substrate with adhesive regions that can collectively hold and transfer multiple devices, thereby dramatically increasing throughput and reducing manufacturing time.
Solution Approach 2:
The patent applies preliminary action by pre-attaching multiple micro-devices to a transfer substrate before the actual transfer to the destination substrate. The adhesive layer is prepared in advance on the transfer substrate, and devices are positioned and held in place during intermediate steps, enabling efficient batch transfer operations that reduce overall manufacturing time compared to individual placement.
2Ease of manufacture
If microLEDs are deposited directly on final display substrate, then integration is simplified, but technical hurdles prevent successful fabrication
Solution Approach 1:
The patent segments the fabrication process into distinct stages: growing microLEDs on a separate donor substrate under optimized conditions, transferring them to an intermediate transfer substrate, and finally placing them on the destination substrate. This segmentation allows each stage to be optimized independently, avoiding the technical hurdles of direct deposition while maintaining fabrication simplicity through modular processing.
Solution Approach 2:
The patent introduces a transfer substrate as an intermediary between the donor substrate and the final destination substrate. This intermediary enables the micro-devices to be grown under optimal conditions on the donor substrate, then transferred through controlled adhesive bonding and light-induced release mechanisms, bypassing the technical challenges of direct growth on the final substrate while ensuring reliable integration.
3Adaptability or versatility
If rigid substrate is used for micro-device fabrication, then manufacturing is straightforward, but curved or bendable displays cannot be produced
Solution Approach 1:
The patent changes the physical parameters of the substrate by using flexible or curved substrates instead of rigid ones. The transfer substrate and/or destination substrate can be made from flexible materials that allow bending and curving, enabling the production of flexible displays while maintaining the adhesive-based transfer process. This parameter change allows the same manufacturing methodology to produce both rigid and flexible display types.
Solution Approach 2:
The patent introduces dynamics by allowing the substrate to change shape from flat to curved or bent configurations. The flexible substrate can be dynamically adjusted during and after the transfer process, enabling the production of displays with various geometries including curved and foldable forms, thereby increasing adaptability without significantly complicating the manufacturing process.
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 allows for increased throughput, reduced manufacturing time and cost, and the ability to produce flexible and multi-color displays with improved precision, addressing the inefficiencies of existing transfer techniques.
Implementation Method 1
The first adhesive layer is exposed to illumination in a region that overlaps at least some of the treated portion and at least some of the untreated portion, and exposing the first adhesive layer to illumination neutralizes the at least some of the untreated portion
Data Source
AI summary
A method of transferring micro-devices includes attaching micro-devices to one surface of a first body with a first adhesive layer, and selectively forming a masking layer on an opposite surface of the first body. A second adhesive layer on a second body is placed to contact the plurality of micro-devices. The first adhesive layer is exposed to illumination through the first body to create a neutralized portion while the masking layer blocks the illumination from reaching some of first adhesive layer to provide a less exposed portion that is more adhesive than the neutralized portion. The first surface is separated from the second surface such micro-devices on the less exposed portion of the first adhesive layer remain attached to the first surface and micro-devices corresponding to the neutralized portion attach to the second body and separate from the first surface.