Microdevice Transfer Bonding for System Substrate Integration
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Solution Overview
Problem
Existing technologies face challenges in efficiently transferring microdevices from a donor substrate to a system substrate with enhanced bonding and conductivity capabilities.
Innovation Solution
A method involving the deposition of conductive layers, patterning to form pixelated structures, providing bonding contacts, and transferring microdevices to an intermediate substrate, followed by integration onto a system substrate, ensuring reliable bonding and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microdevices are transferred from donor substrate to system substrate, then integration efficiency is improved, but bonding reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by depositing conductive layers (first conductive layer 112, second conductive layer 116) and bonding contacts (122, 124) on the donor substrate before microdevice fabrication. This pre-establishment of conductive pathways ensures reliable electrical connections are already in place before the complex transfer process, resolving the contradiction between transfer efficiency and bonding reliability.
Solution Approach 2:
The patent uses an intermediate substrate (104) as a mediator in the transfer process. Microdevices are first transferred to the intermediate substrate, then subsequently transferred to the final system substrate (102). This two-stage transfer approach with an intermediate substrate maintains bonding reliability by providing a stable platform during the transfer process while still achieving high integration efficiency through batch processing.
2Reliability
If conductive layers are deposited to enhance conductivity, then electrical conductivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into the conductive layers. The first conductive layer (112) serves as both a structural support element and an electrical conductor. The second conductive layer (116) simultaneously provides electrical connectivity and acts as a bonding surface for bonding contacts. This merging of structural and electrical functions reduces manufacturing complexity while maintaining high electrical conductivity.
Solution Approach 2:
The bonding contacts (122, 124) are designed with multi-functionality. They serve as electrical connection points for the microdevices while also acting as mechanical anchors during the transfer process and providing thermal conduction pathways. This universal design approach enhances electrical conductivity without proportionally increasing manufacturing complexity.
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 efficient transfer of microdevices with improved bonding and conductivity, facilitating the integration of microdevices into system substrates like display devices and backplanes.
Implementation Method 1
depositing a first conductive layer on the donor substrate, depositing a fully or partially continuous light emitting functional layer on the first conductive layer, depositing a second conductive layer on the functional layer
Implementation Method 2
providing a bonding contact for each pixelated structure, fixing the bonding contact to a system substrate; connecting pads on the microdevices and corresponding pads on the backplane to bond a selective set of the microdevices from the substrate to the backplane
Data Source
AI summary
In a micro-device integration process, a donor substrate is provided on which to conduct the initial manufacturing and pixelation steps to define the micro devices, including functional, e.g. light emitting layers, sandwiched between top and bottom conductive layers. The microdevices are then transferred to a system substrate for finalizing and electronic control integration. The transfer may be facilitated by various means, including providing a continuous light emitting functional layer, breakable anchors on the donor substrates, temporary intermediate substrates enabling a thermal transfer technique, or temporary intermediate substrates with a breakable substrate bonding layer.