Temperature-Controlled Stiffness Transfer Elements for Micro-Object Handling
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Solution Overview
Problem
Current methods for transferring micro-objects, such as microLED chiplets, face challenges in selectively and accurately transferring large numbers of small objects while maintaining high position registration, especially in manufacturing processes where arbitrary patterns are required, and existing technologies like elastomer stamps cannot handle defective chiplets effectively.
Innovation Solution
A transfer substrate with transfer elements that have a higher Young's modulus at lower temperatures and a lower Young's modulus at higher temperatures, allowing for selective adhesion and release of objects through temperature-controlled adhesion elements, enabling the transfer of specific subsets of micro-objects from a donor substrate to a target substrate with high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If elastomer stamps are used for transferring micro-objects, then the transfer process can be simplified, but the ability to selectively transfer specific objects and handle defective chiplets is lost
Solution Approach 1:
The transfer substrate is divided into multiple independently controllable transfer elements, each capable of selective adhesion and release. This segmentation allows individual elements to be controlled separately, enabling selective transfer of specific micro-objects while maintaining a simplified overall transfer process.
Solution Approach 2:
The transfer elements dynamically change their adhesion properties by transitioning between rigid and soft states through temperature control. This dynamic behavior enables the system to adapt between different transfer modes, providing both selective transfer capability and process simplicity.
2Device complexity
If a single transfer substrate is used for all objects, then the device structure is simplified, but the ability to selectively control individual transfer elements is reduced
Solution Approach 1:
The unified transfer substrate is segmented into multiple independently addressable transfer elements. Each element can be individually controlled through separate heating elements, allowing selective operation while maintaining the structural simplicity of a single substrate platform.
Solution Approach 2:
Heating elements serve as intermediaries between the control system and transfer elements. By controlling the temperature of each transfer element through its heating element, selective adhesion and release can be achieved without complex mechanical control mechanisms.
3Manufacturing precision
If temperature-controlled adhesion elements are used, then selective and precise transfer is enabled, but the system complexity and energy consumption increase
Solution Approach 1:
The system replaces complex mechanical control mechanisms with thermal control. By using temperature to control the adhesion state of transfer elements, the system achieves precise control with simpler actuation mechanisms compared to traditional mechanical systems.
Solution Approach 2:
The adhesion properties of transfer elements are controlled by changing the temperature parameter. This parameter change induces a transition between rigid and soft states, enabling precise control over adhesion and release without requiring complex mechanical adjustments.
4Productivity
If conventional transfer methods are used, then the process is straightforward, but the ability to replace defective chiplets and achieve high-yield manufacturing is limited
Solution Approach 1:
The transfer process uses periodic temperature cycling to enable repeated adhesion and release cycles. This periodic action allows multiple transfer operations to be performed on the same substrate, enabling defect replacement and rework while maintaining high manufacturing yield.
Solution Approach 2:
The system enables discarding of defective chiplets by selectively releasing them from the transfer substrate, and recovering functional chiplets for re-transfer. This capability allows defect management and yield improvement without requiring complete process restarts.
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
Enables the selective and precise transfer of micro-objects, allowing for the replacement of defective chiplets and facilitating high-yield manufacturing processes like microLED display assembly by allowing reversible and repeatable adhesion, thereby improving the efficiency and accuracy of micro-object assembly.
Implementation Method 1
Each of the transfer elements includes an adhesion element having a higher Young's modulus at a lower temperature and a lower Young's modulus at a higher temperature
Implementation Method 2
Each transfer element has a heating element operable to change an operating temperature of the adhesion element in response to an input
Data Source
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AI summary
Transfer elements include an adhesion element having a higher Young's modulus at a lower temperature and a lower Young's modulus at a higher temperature. Heating elements are operable to change an operating temperature of each adhesion element in response to an input. A controller is coupled to provide the inputs to the heating elements to cause a change in temperature at least between the higher and lower temperature. The change in temperature causes the transfer elements to selectably hold objects to and release the objects in response to changes between the higher and lower Young's moduli of transfer elements