Micro-Device Adhesive Transfer for Precise MicroLED Placement
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Solution Overview
Problem
The manufacturing of microLED panels with micron-scale LEDs based on III-V semiconductor technology faces challenges such as technical and manufacturing hurdles, particularly in depositing and growing III-V semiconductor microLEDs directly on a final display substrate, and is difficult to produce in curved or bendable displays.
Innovation Solution
A method for transferring micro-devices involves selectively treating an adhesive layer on a donor substrate to create treated and untreated portions, allowing for precise separation and alignment of micro-devices onto a destination substrate using illumination, enabling high precision and increased throughput, and allowing for the transfer of micro-devices to flexible or curved substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If microLEDs are deposited directly on a final display substrate, then integration is achieved, but manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The manufacturing process is segmented into distinct stages: growing microLEDs on a separate donor substrate, transferring them to a transfer substrate, and finally placing them on the destination substrate. This segmentation allows each substrate to be optimized for its specific function, avoiding the complexity of direct deposition while achieving integration.
Solution Approach 2:
A transfer substrate is introduced as an intermediary component between the donor substrate and the destination substrate. This intermediary enables the microLEDs to be grown under optimal conditions on the donor substrate, then transferred via the transfer substrate to the final display substrate, simplifying the overall manufacturing process.
2Manufacturing precision
If microLEDs are transferred using conventional methods, then transfer is achieved, but precision and alignment accuracy deteriorate
Solution Approach 1:
Alignment marks are pre-formed on both the donor substrate and transfer substrate before the transfer process. This preliminary action enables precise alignment during transfer without requiring complex real-time adjustment mechanisms, maintaining both precision and productivity.
Solution Approach 2:
The patent replaces complex mechanical alignment systems with a simplified process using pre-formed alignment marks and controlled substrate positioning. This substitution reduces mechanical complexity while maintaining high precision transfer accuracy.
3Adaptability or versatility
If rigid substrates are used for microLED growth, then fabrication is easier, but flexibility and bendability are lost
Solution Approach 1:
The system is segmented into a rigid donor substrate for easy microLED growth and a flexible destination substrate for the final application. This segmentation allows each substrate to be chosen based on its optimal properties, achieving both ease of manufacture and flexibility.
Solution Approach 2:
The patent changes the substrate material parameter from rigid to flexible at the transfer stage. MicroLEDs are grown on rigid substrates under controlled conditions, then transferred to flexible substrates, allowing the final display to achieve bendability while maintaining manufacturing ease.
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 the efficient transfer of micro-devices with high precision, increasing yield and reducing manufacturing time and cost, enabling the production of multi-color displays and flexible displays with microLEDs, and accommodating different pitch arrangements between the donor and destination substrates.
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 selectively treating a first adhesive layer to form a treated portion and an untreated portion while micro-devices are attached the first adhesive layer. A second adhesive layer on a second surface is placed to abut the micro-devices. 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. Exposing the first adhesive layer to illumination neutralizes the at least some of the untreated portion to create a neutralized portion that is less adhesive than an exposed area of the treated portion. The first surface is separated from the second surface such that micro-devices in the treated portion remain attached to the first surface and micro-devices in the neutralized portion are attached to the second surface and separate from the first surface.