Micro LED Receiving Structure for Single-Step Substrate Transfer
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Solution Overview
Problem
Integration and packaging issues, such as transfer wafer de-bonding and complex bonding/de-bonding steps, hinder the commercialization of micro devices like RF MEMS, LED display systems, and quartz-based oscillators in traditional micro device transfer technologies.
Innovation Solution
A method and structure for receiving micro devices on a substrate, involving a conductive layer, a micro LED device with a p-n diode and quantum well layer, and a thermoplastic or thermoset passivation layer, where the micro device is punched through and secured using electrostatic pick-up and curing techniques, allowing for efficient transfer and integration into display or lighting substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional wafer bonding and transfer printing methods are used to transfer micro devices, then device transfer capability is achieved, but process complexity increases due to multiple bonding and de-bonding steps
Solution Approach 1:
The patent extracts and eliminates the transfer wafer from the traditional transfer printing process. Devices are transferred directly from the donor wafer to the receiving substrate through a single bonding step, removing the intermediate transfer wafer that causes multiple bonding and de-bonding operations. This simplifies the overall process while maintaining device transfer capability.
Solution Approach 2:
The patent employs asymmetric bonding where the receiving substrate has enhanced bonding characteristics compared to the donor wafer. By making the receiving substrate more bondable than the donor wafer, devices preferentially bond to the receiving substrate in a single step, eliminating the need for subsequent de-bonding from the transfer wafer and re-bonding to the receiving substrate.
2Ease of manufacture
If traditional transfer printing with elastomeric stamps is used, then device transfer is achieved, but manufacturing cost and time increase due to sequential processing
Solution Approach 1:
The patent merges the bonding operations into a single simultaneous step where multiple devices are transferred from the donor wafer to the receiving substrate together. This parallel processing approach eliminates the sequential nature of traditional elastomeric stamp methods, significantly improving productivity and reducing manufacturing time while maintaining ease of device transfer.
3Reliability
If micro LED devices are integrated using conventional methods, then device functionality is achieved, but power consumption increases and battery life decreases
Solution Approach 1:
The patent changes the physical and electrical parameters of the micro LED devices through precise control of the bonding process and device structure. By optimizing parameters such as contact area, bonding pressure, and electrical connection quality, the devices achieve superior electrical characteristics with reduced resistance and more efficient current flow, leading to lower power consumption while maintaining full functionality.
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 high-yield, cost-effective, and energy-efficient integration of micro devices with significant power savings and improved battery life by combining wafer-based electronics with thin film technologies, facilitating the transfer of micro LED devices into active or passive matrix OLED backplanes.
Implementation Method 1
picking up a micro device from a carrier substrate with a transfer head
Implementation Method 2
secured using electrostatic pick-up and curing techniques
Data Source
AI summary
A method and structure for receiving a micro device on a receiving substrate are disclosed. A micro device such as a micro LED device is punched-through a passivation layer covering a conductive layer on the receiving substrate, and the passivation layer is hardened. In an embodiment the micro LED device is punched-through a B-staged thermoset material. In an embodiment the micro LED device is punched-through a thermoplastic material.