13 results on '"Vanfleteren, Jan"'
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2. Reducing out-of-plane deformation of metal interconnects in structural electronics
- Author
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Vanfleteren Jan, Madadnia Behnam, and Bossuyt Frederick
- Subjects
Fabrication ,Meander (mathematics) ,Materials science ,Stack (abstract data type) ,Stretchable electronics ,Delamination ,Copper interconnect ,Mechanical engineering ,Electronics ,Deformation (meteorology) - Abstract
This paper presents a novel approach for removing out-of-plane deformation in metal interconnects by adding a fractional structure to the original meander shape and using the optimised fabrication stack. In thermoformed electronics in cases where copper is used as the conductor, the twisting of meander-shaped structures caused by excessive mechanical stress can cause a non-uniform surface, delamination of the metal interconnect from the substrate, and in some cases, a short circuit to the adjacent tracks. Typically, stretchable electronics designers use various shapes and widths of the copper interconnect to tackle this issue. Using conventional meander shapes such as horseshoes and U shapes is not universally practical, especially when stretching is higher than 30 percent leading to significant out-of-plane deformation. Limiting this out-of-plane deformation by reducing the track width is not always applicable, as a minimum width is needed from a technology and conductivity perspective. The presented approach is inspired by computational and experimental studies of multiple meander shapes and fabrication methods. A geometry-based and fabrication-based approach is presented, which can reduce the mechanical stress of almost all possible meander shapes by increasing the meander’s path length to accommodate the metal track’s produced torque during stretching. An analytical approach is provided for calculating the optimal meander parameters, and the optimal fabrication stack is achieved based on simulation results. Experiments and finite-element modeling for an industrial case study show the improvement in the stress distribution and reduction of out-of-plane.
- Published
- 2021
3. Design Automation of Meandered Interconnects for Stretchable Circuits.
- Author
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Plovie, Bart, Vanfleteren, Jan, Vervust, Thomas, Vasquez Quintero, Andres, and Bossuyt, Frederick
- Subjects
- *
INTEGRATED circuit interconnections , *AUTOMATION , *DESIGN services - Abstract
Many of today’s stretchable interconnection technologies make extensive use of meandered interconnections, these provide 2-D in-plane springs capable of extending and compressing as the need arises. While a significant quantity of research work exists on these interconnects, few generic methodologies exist to design circuits in a consistent manner. This shortfall leads to questionable design practices, which can negatively affect reliability and performance. Presented within this paper is a method to quickly determine which meander fits within a given area based on common geometric boundary conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. PCB technology based stretchable circuits
- Author
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Vanfleteren, Jan, Gonzalez, Mario, Bossuyt, Frederick, Vervust, Thomas, De Wolf, Ingrid, and Jablonski, Michal
- Subjects
Technology and Engineering ,PCB ,Hardware_INTEGRATEDCIRCUITS ,Stretchable Electronics ,Smart Textiles ,Printed Circuit Boards - Abstract
In the past 15 years, stretchable electronic circuits have emerged as a new technology in the domain of assembly, interconnections, and sensor circuit technologies. In the meantime, a wide variety of processes using many different materials have been explored in this new field. In the current contribution, we present an approach inspired by conventional rigid and flexible printed circuit board (PCB) technology. Similar to PCBs, standard packaged, rigid components are assembled on copper contact pads using lead-free solder reflow processes. Stretchability is obtained by shaping the copper tracks as horseshoe-shaped meanders. Elastic materials, predominantly polydimethylsiloxanes, are used to embed the conductors and the components, thus serving as a circuit carrier. We describe mechanical modeling, aimed at optimizing the build-up toward maximum mechanical reliability of the structures. Details on the production process, reliability assessment, and a number of functional demonstrators are described.
- Published
- 2013
5. Flexible and stretchable electronics
- Author
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Vanfleteren, Jan
- Subjects
Technology and Engineering ,stretchable electronics ,Ultra-thin chip package ,Hardware_INTEGRATEDCIRCUITS ,Hardware_PERFORMANCEANDRELIABILITY ,flexible ,UTCP ,stretchable circuits ,wearable - Abstract
Conventionally electronics circuits are produced by assembly of packaged components on flat, rigid printed circuit boards. However there is a growing demand for 2.5 dimensional (2.5D free form surfaces) or even full 3D electronics. Applications for such circuits are found in a vast range of fields: such circuits are desirable for comfort and ergonomic reasons (e.g. in wearable or implantable circuits), to respond to design and aesthetics considerations (e.g. 2.5D or 3D light sources), for ecological reasons (more efficient materials usage, less CO2 emissions in automotive applications) etc. In this contribution we will present two technologies, under development at our laboratory, which open the way to industrial production of randomly deformable circuits. These technologies are : • The ultra-thin chip package (UTCP) technology, by which bare Si (or other anorganic semiconductor based) chips are thinned down to a thickness of 20-30µm, embedded in a stack of spin-on polyimide layers, and provided with a fan-out metallization, resulting in an extremely miniaturized, lightweight and flexible chip package with a total thickness below 100µm • A number of technologies for dynamically stretchable (i.e. elastic) circuits, which are based on the interconnection of individual components or component islands with meander shaped thin-film or Printed Circuit Board (PCB) based metal wirings and embedding in elastic polymers like PDMS (silicone rubbers) or PU (polyurethanes). Process flow details, reliability data and applications for these technologies will be presented.
- Published
- 2013
6. From Fibrils to Toughness: Multi-Scale Mechanics of Fibrillating Interfaces in Stretchable Electronics.
- Author
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van der Sluis, Olaf, Vermeij, Tijmen, Neggers, Jan, Vossen, Bart, van Maris, Marc, Vanfleteren, Jan, Geers, Marc, and Hoefnagels, Johan
- Subjects
ELASTOMERS ,FRACTURE toughness ,DIMETHYLPOLYSILOXANES ,DELAMINATION of composite materials ,ELASTICITY ,ENERGY dissipation - Abstract
Metal-elastomer interfacial systems, often encountered in stretchable electronics, demonstrate remarkably high interface fracture toughness values. Evidently, a large gap exists between the rather small adhesion energy levels at the microscopic scale (‘intrinsic adhesion’) and the large measured macroscopic work-of-separation. This energy gap is closed here by unravelling the underlying dissipative mechanisms through a systematic numerical/experimental multi-scale approach. This self-containing contribution collects and reviews previously published results and addresses the remaining open questions by providing new and independent results obtained from an alternative experimental set-up. In particular, the experimental studies on Cu-PDMS (Poly(dimethylsiloxane)) samples conclusively reveal the essential role of fibrillation mechanisms at the micro-meter scale during the metal-elastomer delamination process. The micro-scale numerical analyses on single and multiple fibrils show that the dynamic release of the stored elastic energy by multiple fibril fracture, including the interaction with the adjacent deforming bulk PDMS and its highly nonlinear behaviour, provide a mechanistic understanding of the highwork-of-separation. An experimentally validated quantitative relation between the macroscopic work-of-separation and peel front height is established from the simulation results. Finally, it is shown that a micro-mechanically motivated shape of the traction-separation law in cohesive zone models is essential to describe the delamination process in fibrillating metal-elastomer systems in a physically meaningful way. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. Arbitrarily Shaped Rigid and Smart Objects Using Stretchable Interconnections.
- Author
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Chtioui, Imen, Bossuyt, Frederick, de Kok, Margreet, Vanfleteren, Jan, and Bedoui, Mohamed Hedi
- Subjects
ELECTRONIC circuit design ,THERMOPLASTICS ,PRINTED circuit design ,COPPER research ,POLYETHYLENE - Abstract
In this paper, we present the developments of a new technology to realize 2.5-/3-D electronic circuits. The starting point is an electronic circuit embedded in a hard thermoplastic material, which is transformed into a 2.5-/3-D shape using a thermoforming process. The electronic circuit consists of stretchable copper interconnections in combination with electronic components. The circuit is produced using conventional printed circuit board process steps: a copper sheet is laminated on a thermoplastic material, such as Polycarbonate (PC) or Polyethylene Terephthalate Glycol (PET-G). The copper is structured using lithography and wet etching, and the electronic components are assembled using conductive adhesives. We investigated the use of different designs for stretchable interconnects to overcome the stretching of the electronic circuit by thermoforming it. A semispherical-shaped mold was used for this purpose where the local strain of the substrate can reach 100% with a sharp bending. It was shown that meander-shaped interconnects could accommodate the gradual deformation during the forming of the substrate either for PC and PET-G. However, at the mold’s edge, the copper-meandered tracks showed a delamination of the copper from the substrate. In the meanwhile, the electrical conductivity of the copper tracks did not show any significant variation. Another meander design based on an elliptical shape (in order to increase the length of the track) is proposed and compared with the first design. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
8. Testing for Wearability and Reliability of TPU Lamination Method in E-Textiles.
- Author
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Veske, Paula, Bossuyt, Frederick, and Vanfleteren, Jan
- Subjects
ELECTROTEXTILES ,TEST reliability ,STRAINS & stresses (Mechanics) ,KNIT goods - Abstract
Electronic textiles (e-textiles) and wearable computing have been emerging increasingly during the last decade. Since the market interest and predictions have grown, the research into increasing reliability and durability of wearables and e-textiles is developing rapidly. The washability of different integration methods and resistance to mechanical stress are the main obstacles being tackled. However, the freedom of movement and overall comfort is still often overlooked during the development phase. It is essential to see the e-textile product as a whole and consider several aspects of user experience. This work will focus on developing and improving the thermoplastic polyurethane (TPU) lamination integration method for e-textiles. In the work, a stretchable copper-polyimide based circuit was laminated onto knit fabric using various TPU films and stacks. The study shares measurable characteristics to determine which material assembly and design would ensure the highest durability for the electronics part without losing its original textile softness, flexibility and stretchability. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. Stretchable Electronics Technology for Large Area Applications: Fabrication and Mechanical Characterization.
- Author
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Bossuyt, Frederick, Vervust, Thomas, and Vanfleteren, Jan
- Subjects
APPLICATION software ,MICROFABRICATION ,MECHANICAL properties of polymers ,STRAINS & stresses (Mechanics) ,ELECTRICAL conductors ,POLYDIMETHYLSILOXANE - Abstract
The development and mechanical characterization of a novel technology for stretchable electronics is presented, which can be used for the realization of wearable textile electronics and biomedical implants. The stretchable devices consist of rigid or flexible component islands interconnected with stretchable meander-shaped copper conductors embedded in a stretchable polymer, polydemethylsiloxane. The technology uses standard printed circuit board manufacturing steps and liquid injection molding techniques to achieve a robust and reliable product. The conductors in the device are designed to accommodate strains up to 10–15%. Spin-on photo-definable polyimide as mechanical support for the stretchable interconnects and the functional flexible islands are introduced. By use of polyimide, the reliability of the stretchable interconnects, the straight interconnects on the flexible islands and the transitions between the stretchable and nonstretchable parts are improved. Long-term endurance behavior of the stretchable interconnects is studied by cyclic elongation at strain ranges of up to 20% while monitoring the electrical connectivity. It's shown that the lifetime of the polyimide supported interconnects is at least two times better compared to the nonsupported. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
10. Integration of stretchable and washable electronic modules for smart textile applications.
- Author
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Vervust, Thomas, Buyle, Guy, Bossuyt, Frederick, and Vanfleteren, Jan
- Subjects
ELECTRONICS ,TEXTILES ,POLYDIMETHYLSILOXANE ,LIGHT emitting diodes ,PRINTED circuits ,ELECTRONIC circuits - Abstract
Today electronics in “wearable systems” or “smart textiles” are mainly realised on traditional interconnection substrates, like rigid printed circuit boards or mechanically flexible substrates. The electronic modules are detachable to allow cleaning and washing of the textile. In order to achieve a higher degree of integration and user comfort, a technology for flexible and stretchable electronic circuits was developed. The electronic system is completely embedded in an elastomer material like polydimethylsiloxane (PDMS, silicone), resulting in soft and stretchable electronic modules. The technology uses standard packaged components (ICs) and meander-shaped copper tracks, so that stretchable systems with complex functionality can be achieved. This paper describes how these stretchable modules can be integrated in textiles. Also the influence of the PDMS on the stretchability of the textile has been examined. A basic electronic module with blinking light emitting diodes (LEDs) was designed and produced to illustrate the textile integration and to perform initial washing tests. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
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11. Design and Manufacturing of Stretchable High-Frequency Interconnects.
- Author
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Huyghe, Benoît, Rogier, Hendrik, Vanfleteren, Jan, and Axisa, Fabrice
- Subjects
ANTENNA feeds ,MEDICAL electronics equipment ,MEDICAL equipment design ,INTEGRATED circuit interconnections ,LASER ablation ,SILICONES in medicine ,BIOCOMPATIBILITY ,TECHNOLOGICAL innovations - Abstract
The increasing number of biomedical applications for electronic systems have led to the need for stretchable electronics in order to significantly enhance the comfort of the user. This paper describes the design and manufacturing process of new stretchable high-frequency interconnects with meander-shaped conductors in a coplanar waveguide topology. The novel interconnects are produced based on laser-ablation of a copper foil, which is then embedded in a highly stretchable bio-compatible silicone material. Measurements on prototypes of the designed stretchable high-frequency interconnects revealed a maximal magnitude of -14 dB for the reflection coefficient and a minimal magnitude of -4 dB for the transmission coefficient in the frequency band up to 3 GHz. The influence of stretch on the performance of the high-frequency interconnects was analyzed using a stretch testing machine. The results showed that nor the magnitude, neither the phase of the transmission coefficient was influenced by elongations up to 20%. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
12. Design and Fabrication of Elastic Interconnections for Stretchable Electronic Circuits.
- Author
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Brosteaux, Dominique, Axisa, Fabrice, Gonzalez, Mario, and Vanfleteren, Jan
- Subjects
ELECTRONIC circuits ,ELECTRIC circuits ,MEDICAL electronics ,ELECTROPLATING ,ELECTRONICS - Abstract
For biomedical and textile applications, the comfort of the user will be enhanced if the electronic circuits are not only flexible but also elastic. This letter reveals a simple moulded-interconnect-device technology for the construction of elastic point-to-point interconnections, based on 2-D spring-shaped metallic tracks, which are embedded in a highly elastic silicone film. Metal interconnections of 3-cm long were constructed with an initial resistance of about 3 Ω, which did not significantly increase (< 5%) when stretched. A stretchability above 100% in one direction has been demonstrated. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
13. Flexible and stretchable electronics for wearable health devices.
- Author
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van den Brand, Jeroen, de Kok, Margreet, Koetse, Marc, Cauwe, Maarten, Verplancke, Rik, Bossuyt, Frederick, Jablonski, Michael, and Vanfleteren, Jan
- Subjects
- *
ELECTRONICS , *WEARABLE antennas , *PHYSICAL measurements , *CONCRETE , *ELECTRIC properties of materials - Abstract
Measuring the quality of human health and well-being is one of the key growth areas in our society. Preferably, these measurements are done as unobtrusive as possible. These sensoric devices are then to be integrated directly on the human body as a patch or integrated into garments. This requires the devices to be very thin, flexible and sometimes even stretchable. An overview of recent technology developments in this domain and concrete application examples will be discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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