Flexible Device Transfer via Sacrificial Substrate
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Solution Overview
Problem
Current methods for manufacturing flexible solar cells face challenges such as sagging effects, contraction, and alignment issues due to the use of uneven PDMS stamps, and limitations in etching large areas, which hinder the production of high-efficiency flexible devices like solar cells and light emitting devices.
Innovation Solution
A method involving a sacrificial silicon substrate, where a device layer is transferred onto a flexible polyester (PET)-based substrate using an adhesion layer of polyurethane, and the sacrificial substrate is removed using a specific etchant mixture, ensuring precise alignment and maintaining a flat structure, even for large area devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PDMS stamp is used for selective transfer of microstructure semiconductor, then transfer capability is achieved, but sagging effect occurs causing separation of undesired microstructure semiconductor
Solution Approach 1:
The patent introduces a sacrificial substrate as an intermediary layer between the device layer and the flexible substrate. This mediator enables the device layer to be transferred without direct contact with the PDMS stamp, eliminating the sagging effect and alignment issues caused by the uneven stamp surface while maintaining transfer capability.
Solution Approach 2:
The device layer is first formed on the sacrificial substrate before transfer. The sacrificial substrate is prepared in advance with the device layer, and then the entire assembly is transferred to the flexible substrate. This preliminary arrangement on a flat sacrificial substrate avoids alignment problems during the transfer process.
2Ease of manufacture
If silicon substrate is etched downward from top surface, then device separation is achieved, but unit device area is limited to about 100 μm
Solution Approach 1:
Instead of etching the silicon substrate downward from the top surface, the patent inverts the approach by forming the device layer on the sacrificial substrate first, then transferring the entire assembly. This inversion allows large area devices to be manufactured without being constrained by etchant infiltration limitations.
Solution Approach 2:
The patent segments the manufacturing process into two independent stages: (1) device layer formation on sacrificial substrate, and (2) transfer to flexible substrate. This segmentation allows the device layer to be formed with large area without etching limitations, and the sacrificial substrate to be removed after transfer, achieving both large area capability and clean separation.
3Adaptability or versatility
If microstructure semiconductor is transferred onto flexible substrate, then flexible device is realized, but manufacturing cost increases
Solution Approach 1:
The sacrificial substrate serves multiple functions: it provides a flat platform for device layer formation, acts as a support during transfer, and is completely removed after transfer. This multi-functionality simplifies the overall manufacturing process and reduces costs by eliminating the need for complex alignment and transfer mechanisms.
Solution Approach 2:
The sacrificial substrate acts as a temporary mediator that enables cost-effective manufacturing. By using a simple sacrificial substrate instead of complex direct transfer methods, the patent reduces manufacturing complexity and cost while achieving the desired flexible device structure.
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 enables the manufacturing of flexible solar cells and light emitting devices with superior alignment and reduced manufacturing costs, overcoming the limitations of existing technologies by preventing deformation and allowing for the production of large area devices with high efficiency.
Implementation Method 1
the sacrificial substrate is removed through immersion into an etchant, the etchant being a mixture in which a component A (Ammonium hydrogen fluoride + Ammonium nitrate) and a component B (dilute sulfuric acid) are mixed at a ratio of about 1:1 to about 1:2
Implementation Method 2
an adhesion layer is disposed on a surface of the first flexible substrate contacting the one surface of the device layer
Data Source
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AI summary
Provided are a method of manufacturing a flexible device, the flexible device, a solar cell, and a light emitting device. The method of manufacturing a flexible device includes providing a device layer on a sacrificial substrate, contacting a flexible substrate on one side surface of the device layer, and removing the sacrificial substrate. A large area device may be transferred onto the flexible substrate with superior alignment to realize and manufacture the flexible device. In addition, since mass production is possible, the economic feasibility may be superior. Also, when a large area solar cell having a thin thickness is manufactured, since a limitation such as twisting of a thin film of a solar cell may be effectively solved, the economic feasibility and stability may be superior.