Micro-LED Array Substrate Adhesive Patterning for Accurate Die Transfer
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Solution Overview
Problem
The existing methods for fabricating micro-LED light-emitting device array substrates face issues such as inaccurate die transfer, defects like die skew or cracking, and increased fabrication costs due to the need for additional optical inspection and defect removal processes.
Innovation Solution
The proposed solution involves designing a light-emitting device array substrate with adhesive patterns on a carrier, where the area of the adhesive pattern surface adjacent to the light-emitting device is less than or equal to the device surface, and the spacing between the adhesive pattern center and device center is controlled, allowing for precise alignment and removal of defective devices during the transfer process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple mass transfer techniques are used to fabricate micro-LED light-emitting device array substrates, then the micro-LED dies can be transferred to the driving substrate, but uneven distribution of impact force causes inaccurate die transfer and defects such as die skew or cracking
Solution Approach 1:
The adhesive layer is segmented into multiple discrete adhesive patterns arranged in an array, where each adhesive pattern corresponds to a specific micro-LED die position. This segmentation allows for localized adhesion control and enables the use of laser impact force to be distributed evenly across multiple adhesive patterns, preventing die skew and cracking while maintaining transfer accuracy.
2Reliability
If an automatic optical inspection machine and laser defect removal are used to address transfer defects, then defective dies can be identified and removed, but fabrication hours and costs increase
Solution Approach 1:
The adhesive patterns are designed with specific geometric configurations and dimensions before the transfer process, enabling the laser impact force to be distributed evenly and preventing die skew and cracking from occurring in the first place. This preliminary design eliminates the need for subsequent defect detection and removal processes, reducing fabrication time and costs.
3Manufacturing precision
If the area of adhesive pattern surface adjacent to the light-emitting device is made smaller than or equal to the device surface, then transfer accuracy is improved and defective devices can be eliminated, but adhesive coverage is reduced
Solution Approach 1:
The adhesive patterns are designed with non-uniform geometric configurations where the area of the first surface adjacent to the light-emitting device is controlled to be smaller than or equal to the device surface area. This local quality control ensures that the adhesive provides sufficient bonding while allowing the laser impact force to be distributed evenly, improving transfer accuracy and enabling elimination of defective devices.
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 reduces fabrication hours and costs by ensuring high transfer accuracy and eliminating the need for additional defect removal processes, resulting in a substrate with improved yield and reduced defects.
Implementation Method 1
The micro-LED dies are temporarily fixed on different temporary carriers through an adhesive material
Implementation Method 2
die separation can be accomplished using laser transfer techniques. Further, the generated impact force or driving force may cause the die to be detached and push the die to transfer to the target carrier
Data Source
AI summary
A light-emitting device array substrate includes a carrier, a plurality of adhesive patterns, and a plurality of light-emitting devices. The adhesive patterns are arranged in an array on the carrier. Each of the light-emitting devices is disposed on a first adhesive pattern among the adhesive patterns. An area of a first surface of each of the first adhesive patterns adjacent to the light-emitting device is less than or equal to an area of a second surface of the light-emitting device adjacent to the first adhesive pattern. A method for fabricating a light-emitting device array substrate is also proposed.