Free-form 2.5D thermoplastic circuits using one-time stretchable interconnections (original) (raw)
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MRS Proceedings, 2006
ABSTRACTAn MID (Moulded Interconnect Device) technology was developed for the production of elastic electronic interconnections. The stretchability is obtained using tortuous horseshoe shaped metallic wiring, embedded in a matrix of PDMS (poly dimethyl siloxane). In this way stretchable interconnects have been realized, consisting of 4 micron thick gold wires, embedded in 250 − 500 μm thick silicone material. . Stretchable interconnections, realised with this technology, have a maximum stretchability above 100%, with a stable resistivity of about 1.5 Ω per running cm for a track width of 100μm. A first simple operating stretchable electronic circuit has been fabricated, consisting of a blue LED driven by stretchable wiring. The technology is under development for use in biomedical applications in the first place, but has potential to be extended for various other applications like smart textiles, robotic skins, etc.
2009
A growing need for ambient electronics in our daily life leads to higher demands from the user in the view of comfort of the electronic devices. Those devices should become invisible to the user, especially when they are embedded in clothes (e.g. in smart textiles). They should be soft, conformable and to a certain degree stretchable. Electronics for implantation on the other hand should ideally be soft and conformable in relation to the body tissue, in order to minimize the rejecting nature of the body to unknown implanted rigid objects. Conformable and elastic circuitry is an emerging topic in the electronics and packaging domain. In this contribution a new low cost, elastic and stretchable electronic device technology will be presented, based on the use of a stretchable substrate. The process steps used are standard PCB fabrication processes, resulting in a fast technology transfer to the industry. This new developed technology is based on the combination of rigid standard SMD components which are connected with 2-D spring-shaped metallic interconnections. Embedding is done by moulding the electronic device in a stretchable polymer. The reliability of the overall system is improved by varying the thickness of the embedding polymer, wherever the presence and type of components requires to. Manufacturability issues are discussed together with the need for good reliability of the stretchable interconnections when stress is applied during stretching.
Flexible and Stretchable Circuits for Smart Wearables
Journal of Telecommunication, Electronic and Computer Engineering, 2017
Flexible and stretchable circuits have recently gained traction in the market due to the popularity of wearables and the rapid advancement in microsensors, big data and the Internet of Everything. For devices to be truly wearable, they need to conform to the shape of the human body, allowing ease of use, with sensors being pervasive but not intrusive. To allow this, electronics engineers need to shift their mindsets of manufacturing transistors, circuits and sensors on rigid planar surfaces to flexible, multidimensional and free-form substrates. This review manuscript describes the motivation for designing such circuits, its fabrication techniques, design considerations, performance evaluation and applications. It is expected that stretchable circuits will be a new way forward for integrated circuit technology and will continue to push the boundaries of manufacturing processes in the years to come.
Flex PCB based technology for randomly shaped circuits
2017
In this paper we present a technology for the production of randomly shaped 3D electronic circuits. The technology is based on conventional printed circuit board (PCB) technology, thermoplastic polymer encapsulation and thermoforming of the flat polymer carrier with the embedded circuit. Meander shaped Cu lines between components are stretched during the thermoforming while maintaining their interconnection function. The feasibility of this process has been demonstrated by producing functional free-form LED circuits.