Selective Microdevice Transfer via Release Layer Modification
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Solution Overview
Problem
Existing methods for transferring microdevices from a cartridge substrate to a system substrate lack selectivity, often requiring high forces for bonding and do not allow for precise control over which microdevices are transferred.
Innovation Solution
A method involving the selective modification or removal of a release layer on the cartridge substrate, allowing microdevices to be transferred to the system substrate with a lower force than the bonding force, thereby enabling precise control over which microdevices are transferred.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high bonding force is used to transfer microdevices, then reliable bonding is achieved, but selectivity is lost and all microdevices are transferred
Solution Approach 1:
The patent applies local quality by creating spatial variation in release layer properties across the cartridge substrate. Different regions have release layers with different bonding characteristics, allowing selective transfer of specific microdevices while maintaining strong bonding where needed. This is achieved through selective modification or removal of release layers in specific patterns corresponding to desired transfer locations.
Solution Approach 2:
The patent employs preliminary action by pre-modifying or pre-removing release layers in specific patterns before the transfer process. This preliminary preparation creates predetermined weak bonding zones that enable selective release of specific microdevices when bonding force is applied, allowing control over which devices are transferred without requiring high forces during the actual transfer.
2Strength
If release layer is not modified, then microdevices remain firmly attached to cartridge substrate, but selective transfer cannot be achieved
Solution Approach 1:
The patent creates local quality differences in the release layer properties across the cartridge substrate. By selectively modifying or removing release layers in specific regions, the attachment strength varies spatially, allowing precise control over which microdevices are transferred. This local variation enables both strong overall attachment and precise selective release.
Solution Approach 2:
The patent applies parameter changes by modifying the physical or chemical properties of the release layer in specific regions. This could involve changing the bonding strength, thickness, or material composition of the release layer locally, creating zones with different attachment characteristics that enable precise selective transfer while maintaining strong attachment elsewhere.
3Productivity
If uniform bonding force is applied, then all microdevices can be transferred, but selective transfer is not possible
Solution Approach 1:
The patent resolves this contradiction by creating local quality variations in the release layer that allow uniform bonding force to produce selective transfer. The spatially varying release layer properties ensure that when uniform force is applied, only microdevices over modified regions are transferred, maintaining both efficiency and selectivity.
Solution Approach 2:
The patent uses preliminary action by pre-establishing the selective bonding pattern in the release layer before transfer. This preliminary configuration allows the system to achieve selective transfer with uniform bonding force, eliminating the need for complex force control while maintaining both productivity and selectivity.
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 selective and precise transfer of microdevices to the system substrate, improving the efficiency and accuracy of the transfer process while reducing the force required for bonding.
Implementation Method 1
bonding the selected microdevice to the pads in the system substrate, and where the release layer for the first selected microdevice from the cartridge substrate is modified or removed prior to the transfer such that the selected microdevice is held to the cartridge substrate with a lower force than the bonding force
Data Source
AI summary
The invention disclose method to selectively transfer microdevices from a cartridge substrate to a system substrate by bringing a cartridge substrate closer to the system substrate, wherein the release layer for the first selected microdevice from the cartridge substrate is modified or removed prior to the transfer such that the selected microdevice is held to the cartridge substrate with a lower force than the bonding force of the selected microdevice to the pad.