Dry Module Deposition from Source Wafers onto Flexible Substrates
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Solution Overview
Problem
Current methods for disposing micro-devices on flexible substrates are costly and inefficient, particularly when using incompatible materials with slurry-based techniques, which complicates high-volume production and rough handling applications.
Innovation Solution
A method involving a module source wafer with sacrificial layers and tethers, where modules are released through dry or wet etching, and then physically detached or vibrated to fall into a container, allowing for dry collection and subsequent random dispersion onto a receiving surface using adhesive techniques and surface energy manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If slurry-based transfer printing is used to deposit micro-devices on flexible substrates, then high-volume production is enabled, but the method becomes incompatible with certain flexible substrate materials and increases process complexity
Solution Approach 1:
The patent extracts the micro-devices from the slurry medium and handles them as dry individual components. The etching process releases devices from the wafer one by one or in small groups, allowing direct placement on flexible substrates without requiring slurry-based transfer, thus enabling compatibility with materials that cannot withstand slurry processing.
Solution Approach 2:
The patent introduces an intermediary etching process that acts as a bridge between wafer fabrication and final substrate deposition. This etching step creates a transition state where devices are released but handled individually rather than in slurry, enabling compatibility with diverse flexible substrate materials while maintaining high-volume production capability.
2Reliability
If conventional handling methods are used for micro-devices during deposition, then mechanical stress and damage occur to the devices, but gentle handling reduces productivity
Solution Approach 1:
The etching process itself performs the separation function that would otherwise require mechanical handling. The chemical or physical etching automatically releases devices from the wafer without requiring external manipulation, thereby protecting devices from mechanical stress while maintaining efficient high-volume processing through automated etching.
Solution Approach 2:
The patent replaces mechanical handling and manipulation with an etching-based release mechanism. Instead of using tweezers, pick-and-place tools, or other mechanical systems that could damage micro-devices, the etching process chemically or physically separates devices from the wafer, substituting a gentler non-mechanical method that preserves device integrity while maintaining productivity.
3Manufacturing precision
If individual micro-device placement is performed to ensure proper positioning, then positioning precision is improved, but the process becomes too complex and costly for high-volume applications
Solution Approach 1:
The patent segments the release process so that devices are separated from the wafer in a controlled manner through etching, allowing them to be deposited individually or in small groups rather than as a bulk slurry. This segmentation enables simpler handling and more accurate positioning compared to slurry methods, while avoiding the complexity of fully individualized placement for each device in high-volume production.
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 and cost-effective high-volume deposition of micro-devices onto flexible substrates, reducing mechanical and chemical stress on the modules and improving handling resilience.
Implementation Method 1
dry or wet etching the sacrificial portions to release the modules from the module source wafer
Implementation Method 2
dry or wet etching the sacrificial portions to release the modules from the module source wafer
Implementation Method 3
physically detached from the module source wafer, particularly by mechanically or sonically vibrating the module source wafer
Implementation Method 4
physically detached from the module source wafer, particularly by mechanically or sonically vibrating the module source wafer
Implementation Method 5
directing a stream of gas or liquid onto the module source wafer such that the modules are released from the module source wafer
Implementation Method 6
directing a stream of gas or liquid onto the module source wafer such that the modules are released from the module source wafer
Implementation Method 7
coating a layer of adhesive on the receiving surface that adheres at least some of the modules to the receiving surface
Implementation Method 8
heating the adhesive to reduce the viscosity of the adhesive and orient the modules with respect to the receiving surface
Implementation Method 9
disposing the modules on a receiving surface, particularly by randomly sprinkling the modules onto the receiving surface
Data Source
AI summary
A module collection and deposition system comprises a container, a module source wafer comprising modules released from the module source wafer, a module collection device operable to remove the modules from the module source wafer and dispose the modules as a disordered and dry collection into the container, and a module deposition device for removing the modules from the container and randomly disposing the modules on a receiving surface. Each module comprises an electronically active unpackaged component.