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- Abdollahi Sani, Negar, et al.
(författare)
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All-printed diode operating at 1.6 GHz
- 2014
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 111:33, s. 11943-11948
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Tidskriftsartikel (refereegranskat)abstract
- Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications.
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| 4. |
- Dejanovic, Slavko, et al.
(författare)
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Manufacturing of Via Holes in Silicone Elastomer
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Annan publikation (populärvet., debatt m.m.)abstract
- In this work a possibility of making via holes in silicone elastomer was investigated. The methods that were taken into consideration were punching, mechanical drilling, laser drilling and RIE. Laser drilling and RIE were found to be viable and both were tried. Laser drilling of silicone elastomer has shown a big problem with burnt residues and has to be investigated much further to be usable. RIE of silicone elastomer is reported in this work. Several phenomena were observed. The etch-residues can be removed by washing them away in an ultra sonic water bath and subsequently totally removed by using a lift-off process based on wet Cu etch. A good anisotropy was achieved by applying CF4 plasma. Gradually broadening of the openings in the etch mask has contributed to a favorable etch profile and thus easier metallization of side-walls of via holes.
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| 5. |
- Dejanovic, Slavko, et al.
(författare)
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Metal Covered Elastic Micro-Bump Contacts as an Alternative to Commercial Elastic Interconnection Techniques
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Ingår i: IEEE transactions on components and packaging technologies (Print). - 1521-3331 .- 1557-9972.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this work, a novel chip-to-board interconnection structure have been manufactured, and some of its characteristics have been investigated. This chip connection technique can for instance serve as a FCOB (Flip Chip on Board) technique, for connecting test equipments during testing bare chip on wafer, and with some more development, in three dimensional multi chip modules. A setup of elastic micro-bumps was cast, metal covered, patterned, and electro-mechanically characterized. The metal-covered silicon elastomer contact-structures were manufactured on FR-4 carrier-plates. Visual inspection of the micro-bumps was conducted in a SEM (Scanning Electron Microscope). The electro-mechanical properties were measured by simultaneous use of a DMA (Dynamic Mechanical Analyzer) and a Kelvin Bridge structure for resistance measurement. The measurements gave the micro-bump to chip resistance behavior as a function of the micro-bump deflection distance and applied mechanical force when direct current was applied. The results obtained from the measurements have revealed that such a technique requires less than one tenth of the mechanical contact force for achieving the contact resistance of the same magnitude as for commercial elastic interconnection techniques. This would be of significant advantage because the amount of electrical contacts per unit of area has tendency of continued growth.
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| 6. |
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| 7. |
- Haglund, Daniel, et al.
(författare)
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Metal Covered Elastic Micro-Bump Contacts as an Alternative to Commercial Elastic Interconnection Techniques
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Annan publikation (populärvet., debatt m.m.)abstract
- In this work, a novel chip-to-board interconnection structure have been manufactured, and some of its characteristics have been investigated. This chip connection technique can for instance serve as a FCOB (Flip Chip on Board) technique, for connecting test equipments during testing bare chip on wafer, and with some more development, in three dimensional multi chip modules. A setup of elastic micro-bumps was cast, metal covered, patterned, and electro-mechanically characterized. The metal-covered silicon elastomer contact-structures were manufactured on FR-4 carrier-plates. Visual inspection of the micro-bumps was conducted in a SEM (Scanning Electron Microscope). The electro-mechanical properties were measured by simultaneous use of a DMA (Dynamic Mechanical Analyzer) and a Kelvin Bridge structure for resistance measurement. The measurements gave the micro-bump to chip resistance behavior as a function of the micro-bump deflection distance and applied mechanical force when direct current was applied. The results obtained from the measurements have revealed that such a technique requires less than one tenth of the mechanical contact force for achieving the contact resistance of the same magnitude as for commercial elastic interconnection techniques. This would be of significant advantage because the amount of electrical contacts per unit of area has tendency of continued growth.
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| 9. |
- Hesselbom, Hjalmar, et al.
(författare)
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Solder and Adhesive Free Chip Assembly Using Elastic Chip Sockets: Concept, Manufacture and Preliminary Investigation
- 2004
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Ingår i: Proceedings of 2004 International IEEE Conference on the Asian Green Electronics (AGEC). - Piscataway, NJ, USA : IEEE. - 078038203X ; , s. 12-17
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Konferensbidrag (refereegranskat)abstract
- Flip Chip connections enormously reduces the amount of solder as compared to mounting packaged devices, apart from also offering superior high frequency properties and placement density. However, when assembling chips to substrates having different thermal expansion coefficient, the solder balls are exposed to strain, the more so the denser the connections (and consequently smaller balls), and the higher the power densities, resulting in wider temperature cycles. This will usually result in loss of contact reliability. Using other materials than solder or using underfills may partially improve the situation, but causes other problems. In order to test another concept maintaining or exceeding the excellent HF and density properties of conventional Flip Chip, while practically eliminating the thermal mismatch problems and providing effortless chip replacement, the Elastic Chip Socket was developed. Silicone elastomer was molded in a precision mold made using anisotropic etching of Si. These structures were subsequently metallized and the metal patterned using electro plated resist. So far functional chip sockets with pin densities of 45 000 pins per cm2 (22 500 simultaneously functional connections to a 7 × 7 mm die) and more have been achieved which endure multiple repeated matings and quick temperature cycling between - 40°C and + 90°C. The following is a summary of the group's achievement this far, Oct. 2003.
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