Thin-Film Micro-Transfer Printing with Support Structures for Reliable Pick-Up
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Solution Overview
Problem
Existing micro-transfer printing methods struggle with the reliable pick-up and transfer of thin films due to their increased flexibility, leading to adhesion issues and breakage during the pick-up process, resulting in low yield and reliability.
Innovation Solution
A method involving a source wafer with designed breakable tethers and support structures formed through recesses and sacrificial recesses, which are filled with support material to minimize adhesion and stabilize the device coupon, allowing reliable pick-up and transfer of thin films with high yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thin films are used for device coupons, then flexibility and material diversity are improved, but adhesion to the source wafer increases and reliability deteriorates
Solution Approach 1:
The patent divides the thin film into discrete device coupons with specific geometric configurations. By segmenting the continuous thin film into individual transferable units with controlled dimensions and aspect ratios, the film can be reliably manipulated and transferred despite its inherent flexibility. The segmentation allows each coupon to be independently handled while maintaining structural integrity during the pick-up process.
Solution Approach 2:
The patent introduces an intermediary layer or structure between the thin film and the source wafer that facilitates controlled release. This intermediary mechanism enables the thin film to be reliably transferred by mediating the adhesion and release processes, allowing the film to be picked up without breaking while maintaining material versatility.
2Area of moving object
If thin films with large surface areas are transferred, then device functionality is improved, but the aspect ratio increases and manufacturing precision deteriorates
Solution Approach 1:
The patent employs dynamic control of the transfer process, where the device coupon geometry and suspension characteristics are optimized to allow controlled manipulation during transfer. The dynamic approach enables large surface area devices to be transferred with high precision by adapting the transfer conditions to the specific dimensions and mechanical properties of each coupon.
Solution Approach 2:
The patent systematically varies geometric parameters of the device coupons, such as width, length, and suspension bridge dimensions, to optimize the aspect ratio and transfer characteristics. By changing these parameters, large surface area devices can be transferred with high precision while maintaining manufacturing control and repeatability.
3Ease of operation
If thin films are suspended from source wafer, then transfer capability is improved, but film stability deteriorates and breakage occurs
Solution Approach 1:
The patent implements protective structures or cushioning mechanisms beforehand to prevent film breakage during suspension and transfer. These pre-designed protective features, such as reinforcement patterns or controlled suspension geometries, cushion the thin film against mechanical stresses that would otherwise cause breakage, ensuring both transfer capability and film stability.
Solution Approach 2:
The patent uses composite structures combining the thin film with supporting materials or patterns that provide mechanical stability. This composite approach maintains the functional properties of the thin film while adding structural reinforcement that prevents breakage during suspension and transfer operations.
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
The method enables reliable high-yield heterogeneous integration of thin films by reducing the effective aspect ratio and minimizing adhesion, preventing breakage during pick-up, and allowing for flexible materials with large surface areas to be transferred effectively.
Implementation Method 1
one or more sacrificial layers between the source substrate and the film, wherein the one or more sacrificial layers are at least partially etched away
Implementation Method 2
A support material is provided in at least some pairs of recesses and sacrificial recesses, thereby forming support structures for the device coupon in the sacrificial layer
Data Source
AI summary
A method for forming a device coupon (100) includes providing a source wafer (1) with a source substrate (10); a sacrificial layer (11); and a film (12). At least one device coupon (100) is formed in the film (12). One or more designed breakable tethers is designed to secure the device coupon (100) to the film (12). The method includes etching one or more recesses (111) extending through the device coupon (100), thereby exposing the sacrificial layer (11); and etching the sacrificial layer (11) away at least partially through one or more of the recesses (111), thereby forming one or more sacrificial recesses (121) in the sacrificial layer (11). At least some pairs of recesses (111) and sacrificial recesses (121) are filled with a support material (200), thereby forming support structures (220) for device coupon (100).