| 1. |
- Wang, Teng, 1983, et al.
(författare)
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Through silicon vias filled with planarized carbon nanotube bundles
- 2009
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:48
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Tidskriftsartikel (refereegranskat)abstract
- The feasibility of using carbon nanotube (CNT) bundles as the fillers of through silicon vias (TSVs) has been demonstrated. CNT bundles are synthesized directly inside TSVs by thermal chemical vapor deposition (TCVD). The growth of CNTs in vias is found to be highly dependent on the geometric dimensions and arrangement patterns of the vias at atmospheric pressure. The CNT-Si structure is planarized by a combined lapping and polishing process to achieve both a high removal rate and a fine surface finish. Electrical tests of the CNT TSVs have been performed and their electrical resistance was found to be in the few hundred ohms range. The reasons for the high electrical resistance have been discussed and possible methods to decrease the electrical resistance have been proposed.
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| 2. |
- Zhang, Yong, 1982, et al.
(författare)
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Properties of Undoped Few-Layer Graphene-Based Transparent Heaters
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- In many applications like sensors, displays, and defoggers, there is a need for transparent and efficient heater elements produced at low cost. For this reason, we evaluated the performance of graphene-based heaters with from one to five layers of graphene on flexible and transparent polyethylene terephthalate (PET) substrates in terms of their electrothermal properties like heating/cooling rates and steady-state temperatures as a function of the input power density. We found that the heating/cooling rates followed an exponential time dependence with a time constant of just below 6 s for monolayer heaters. From the relationship between the steady-state temperatures and the input power density, a convective heat-transfer coefficient of 60 W·m−2·°C−1 was found, indicating a performance much better than that of many other types of heaters like metal thin-film-based heaters and carbon nanotube-based heaters.
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| 3. |
- Bao, Jie, et al.
(författare)
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Synthesis and Applications of Two-Dimensional Hexagonal Boron Nitride in Electronics Manufacturing
- 2016
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Ingår i: Electronic Materials Letters. - : Springer Science and Business Media LLC. - 1738-8090 .- 2093-6788. ; 12:1, s. 1-16
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Forskningsöversikt (refereegranskat)abstract
- In similarity to graphene, two-dimensional (2D) hexagonal boron nitride (hBN) has some remarkable properties, such as mechanical robustness and high thermal conductivity. In addition, hBN has superb chemical stability and it is electrically insulating. 2D hBN has been considered a promising material for many applications in electronics, including 2D hBN based substrates, gate dielectrics for graphene transistors and interconnects, and electronic packaging insulators. This paper reviews the synthesis, transfer and fabrication of 2D hBN films, hBN based composites and hBN-based van der Waals heterostructures. In particular, this review focuses on applications in manufacturing electronic devices where the insulating and thermal properties of hBN can potentially be exploited. 2D hBN and related composite systems are emerging as new and industrially important materials, which could address many challenges in future complex electronics devices and systems.
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| 4. |
- Bao, Jie, 1982, et al.
(författare)
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Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging
- 2016
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:July 2016, s. 265501-
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Tidskriftsartikel (refereegranskat)abstract
- The need for electrically insulating materials with a high in-plane thermal conductivity for lateral heat spreading applications in electronic devices has intensified studies of layered hexagonal boron nitride (h-BN) films. Due to its physicochemical properties, h-BN can be utilised in power dissipating devices such as an electrically insulating heat spreader material for laterally redistributing the heat from hotspots caused by locally excessive heat flux densities. In this study, two types of boron nitride based heat spreader test structures have been assembled and evaluated for heat dissipation. The test structures separately utilised a few-layer h-BN film with and without graphene enhancement drop coated onto the hotspot test structure. The influence of the h-BN heat spreader films on the temperature distribution across the surface of the hotspot test structure was studied at a range of heat flux densities through the hotspot. It was found that the graphene-enhanced h-BN film reduced the hotspot temperature by about 8–10°C at a 1000 W/cm2 heat flux density, a temperature decrease significantly larger than for h-BN film without graphene enhancement. Finite element simulations of the h-BN film predict that further improvements in heat spreading ability are possible if the thermal contact resistance between the film and test chip are minimised.
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| 5. |
- Edwards, Michael, 1986, et al.
(författare)
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Finite element simulation of 2D-based materials as heat spreaders
- 2016
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Ingår i: IMAPS Nordic Annual Conference 2016 Proceedings. - 9781510827226
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Konferensbidrag (refereegranskat)abstract
- Since the discovery of graphene, the first discovered 2D material, by Novoselov and Geim in 2004, the field of 2D materials has taken off and about 20 further 2D materials have been found. One of the most promising of these materials for the passive cooling of chips is hBN. HBN has the very unusual combination of being electrically insulating and thermally conductive, which potentially makes it an ideal material for both laterally spreading heat and passivating hotspots on chips. This gives hBN an advantage over graphene, where the chip requires a SiO2 passivation layer to prevent short circuits. To help evaluate the performance of these heat spreading films, a finite element model has been devised to support the experimental work undertaken in various publications. This model has been validated with experimental data and suggests that both graphene-And hBN-based materials have significant potential in lateral heat spreading applications.
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| 6. |
- Huang, Shirong, et al.
(författare)
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Infrared Emissivity Measurement for Vertically Aligned Multiwall Carbon Nanotubes (CNTs) Based Heat Spreader Applied in High Power Electronics Packaging
- 2016
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Ingår i: 6th Electronic System-integration Technology Conference (ESTC 2016). - 9781509014026 ; , s. Article no 7764696-
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Konferensbidrag (refereegranskat)abstract
- Vertically-aligned multiwall carbon nanotubes were deposited on silicon substrate by low pressure chemical vapor deposition (LPCVD), which can be utilized as heat spreaders in high power electronic packaging due to their remarkable thermal conductivity. The infrared emissivity of the vertically aligned multiwall carbon nanotubes was then characterized based on the FLIR SC600 infrared imaging system. The average infrared emissivity of the multiwall carbon nanotubes sample was about 0.92, which agrees well with experimental results reported before. Scanning electron microscopy (SEM) images of the multiwall carbon nanotubes were further analyzed to explain its high emissivity, and the reason can be attributed to the homogeneous sparseness and aligned structure of the vertically aligned multiwall carbon nanotubes
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| 7. |
- Huang, Shirong, et al.
(författare)
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The Effects of Graphene-Based Films as Heat Spreaders for Thermal Management in Electronic Packaging
- 2016
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Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016. - 9781509013968 ; , s. Art no 7583272; Pages 889-892
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Konferensbidrag (refereegranskat)abstract
- Graphene-based films (GBF) were fabricated using a chemical conversion process including graphene oxide (GO) preparation by use of Hummer’s method, graphene oxide reduction using L-ascorbic acid (LAA), and finally film formation by vacuum filtration. GBF is considered as a candidate material for thermal management, i.e. for removing heat from hotspots in power electronic packaging, due to its high thermal conductivity. In this work, the GBF heat spreading performance in 3D TSV packaging was analysed using finite element methods (FEM) implemented in the COMSOL software. Both size effects and the influence of the thermal conductivity of the GBF heat spreader on the thermal performance of the 3D TSV package were evaluated. Furthermore, the size effects of the thermal conductive adhesive (TCA) underfill between the chip and the printed circuit board (PCB) were analysed. The results obtained are critical for proper design of graphene-based lateral heat spreaders in high power electronic packaging.
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| 8. |
- Jeppson, Kjell, 1947, et al.
(författare)
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3D chip stacking using planarized carbon nanotubes as through-silicon-vias
- 2009
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Ingår i: Swedish System on Chip Conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Future miniaturization of advanced electronic systems will require 3D chip-to-chip stacking of high performance processor chips. Such systems raise a number of questions concerning power distribution and thermal management issues. Efficient through-silicon-via (TSV) technology and new thermal interface materials will be required for such systems to be successful. Carbon nanotubes (CNT) have been suggested as a candidate material with good mechanical properties, and good thermal and electrical conductivities superior to those of copper TSVs. In this paper we will describe our efforts on producing through-silicon-vias based on carbon nanotube bundles grown from the bottom of 150 m deep silicon vias with 50*50 µm openings. The resistances of such CNT vias have been electrically measured and found to be about 2.0 kΩ, a result very close to previously reported values. However, these values are orders of magnitude too high for practical use and not at all close to values reported from measurements on short carbon nanotubes. New processes are suggested too improve growth of long CNTs.
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| 9. |
- Jeppson, Kjell, 1947, et al.
(författare)
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Hotspot test structures for evaluating carbon nanotube microfin coolers and graphene-like heat spreaders
- 2016
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Ingår i: 29th IEEE International Conference on Microelectronic Test Structures (ICMTS), Yokohama, Japan, Mar 28-31, 2016. - 1071-9032. ; 2016-May, s. 32-36
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Konferensbidrag (refereegranskat)abstract
- The design, fabrication, and use of a hotspot-producing and temperature-sensing test structure for evaluating the thermal properties of carbon nanotubes, graphene and boron nitride for cooling of electronic devices in applications like 3D integrated chip-stacks, power amplifiers and light-emitting diodes is described. The test structure is a simple meander-shaped metal resistor serving both as the hotspot and the temperature thermo-meter. By use of this test structure, the influence of emerging materials like those mentioned above on the temperature of the hotspot has been evaluated with good accuracy).
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| 10. |
- Jeppson, Kjell, 1947, et al.
(författare)
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Through-Silicon Vias Filled With Densified and Transferred Carbon Nanotube Forests
- 2012
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 33:3, s. 420-422
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Tidskriftsartikel (refereegranskat)abstract
- Through-silicon vias (TSVs) filled with densified and transferred carbon nanotube (CNT) forests are experimentally demonstrated. The filling is achieved by a postgrowth low-temperature transfer process at 200oC instead of direct CNT growth in the vias normally requiring high temperature. A vapor densification method is also applied to densify the as-grown CNT forests, which allows for packing more CNTs in the vias to reduce their resistances. CNT-filled TSVs fabricated based on these two key steps show CMOS compatibility and roughly one order of magnitude reduction in resistivity compared to the TSVs filled with as-grown undensified CNT forests.
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