Single Off-Center Tether for 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 due to unpredictable release of active micro-device components.
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 reliable and predictable release while preserving the spatial configuration 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 release of active micro-device components is unpredictable and lacks precision
Solution Approach 1:
The invention segments the release mechanism by introducing individually addressable tethers for each micro device or group of micro devices. This allows selective release of specific devices while others remain anchored, enabling precise control over which components are transferred and when, thereby improving both manufacturing precision and process reliability.
Solution Approach 2:
The invention applies local quality by creating spatially varying tether configurations where different regions of the native substrate have different tether densities, anchor structures, or tether strengths. This enables differential release behavior across the substrate, allowing precise control over release location and timing for different micro devices.
2Reliability
If multiple tethers per micro-device are used, then spatial configuration is maintained, but release control becomes less precise and reproducibility decreases
Solution Approach 1:
Instead of using multiple tethers per device that release simultaneously, the invention segments the tether system into individually addressable units. Each tether or tether group can be selectively released based on specific criteria, maintaining spatial configuration through controlled sequential release rather than simultaneous release of multiple tethers.
Solution Approach 2:
The invention introduces dynamic control over tether release by making tethers individually addressable through external stimuli such as electrical signals, thermal fields, or mechanical activation. This dynamic control allows the system to transition from static multiple-tether configurations to actively controlled sequential release, improving precision while maintaining spatial integrity.
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 by ensuring complete removal of the sacrificial layer and controlled tether breakage during the transfer process.
Implementation Method 1
selective removal of a sacrificial layer through undercutting or etching
Implementation Method 2
Surface adhesion forces are used to control the selection and printing of these micro devices onto the destination substrate
Data Source
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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.