Single Off-Center Tether for Controlled Micro-Device Release
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Solution Overview
Problem
Conventional micro transfer printing techniques lack reproducibility and precision, leading to inefficiencies and errors in the controlled release of semiconductor micro-devices from native substrates.
Innovation Solution
The use of a single off-center tether per micro-device, combined with selective removal of a sacrificial layer through undercutting or etching, ensures predictable and controlled release, preserving the spatial configuration and orientation of micro-devices during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional micro transfer printing techniques are used, then micro devices can be transferred from native substrate to destination substrate, but the process lacks reproducibility and precision leading to errors
Solution Approach 1:
The patent applies preliminary action by pre-forming a sacrificial layer beneath the micro devices on the native substrate before the transfer process. This sacrificial layer is specifically designed to be selectively removable, creating a controlled release mechanism that ensures precise and reproducible device detachment during transfer printing.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical or chemical properties of the sacrificial layer material to enable selective removal. By choosing materials with specific etch rates, solubility, or thermal properties, the process achieves controlled release of micro devices with high precision and reproducibility during the transfer process.
2Strength
If multiple tethers are used per micro-device, then the micro-device is more securely attached to the substrate, but the complexity of the release process increases
Solution Approach 1:
The patent applies the extraction principle by removing the micro devices from the native substrate through selective removal of the sacrificial layer. This creates a clean detachment mechanism where devices are released without requiring complex tether breaking or detachment procedures, simplifying the overall release process while maintaining secure attachment during transfer.
3Productivity
If conventional transfer printing is used, then high-speed parallel assembly can be achieved, but reproducibility and precision are insufficient for high-density device production
Solution Approach 1:
The patent applies preliminary action by pre-configuring the sacrificial layer structure and tether arrangement before the transfer process. This pre-prepared configuration ensures that when high-speed parallel transfer printing is performed, the devices detach with consistent precision and orientation, enabling both high productivity and accurate placement for high-density device 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
This approach enhances the reproducibility and precision of micro-device assembly, reducing errors and improving the efficiency of micro-device transfer onto destination substrates, enabling high-density electronic device production at low costs.
Implementation Method 1
selective removal of a sacrificial layer through undercutting or etching
Data Source
AI summary
The disclosed technology relates generally to methods and systems for controlling the release of micro devices. Prior to transferring micro devices to a destination substrate, a native substrate is formed with micro devices thereon. The micro devices can be distributed over the native substrate and spatially separated from each other by an anchor structure. The anchors are physically connected/secured to the native substrate. Tethers physically secure each micro device to one or more anchors, thereby suspending the micro device above the native substrate. In certain embodiments, single tether designs are used to control the relaxation of built-in stress in releasable structures on a substrate, such as Si (1 0 0). Single tether designs offer, among other things, the added benefit of easier break upon retrieval from native substrate in micro assembly processes. In certain embodiments, narrow tether designs are used to avoid pinning of the undercut etch front.