| 41. |
- Hansson, Josef, 1991, et al.
(författare)
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Review of Current Progress of Thermal Interface Materials for Electronics Thermal Management Applications
- 2016
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Ingår i: 2016 Ieee 16th International Conference on Nanotechnology (Ieee-Nano). - 9781509014934 ; , s. 371-374
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Konferensbidrag (refereegranskat)abstract
- Increasing power densities within microelectronic systems place an ever increasing demand on the thermal management. Thermal interface materials (TIMs) are used to fill air gaps at the interface between two materials, greatly increasing the thermal conductance when solid surface are attached together. The last decade has provided significant development on high-performing TIMs, and this paper makes a summarized review on recent progress on the topic. Current state of the art commercial TIM types are presented, and discussed in regards to their advantages and disadvantages. Two main categories of TIMs with high interest are then reviewed: continuous metal phase TIMs and carbon nanotube array TIMs.
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| 42. |
- Hansson, Josef, 1991, et al.
(författare)
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Synthesis of a Graphene Carbon Nanotube Hybrid Film by Joule Self-heating CVD for Thermal Applications
- 2018
-
Ingår i: Proceedings - Electronic Components and Technology Conference. - 0569-5503. ; 2018-May
-
Konferensbidrag (refereegranskat)abstract
- Hybrid films based on vertically aligned carbon nanotubes (CNTs) on graphene or graphite sheets have been proposed for application as thermal interface materials and micro heat sinks. However, the fabrication of these materials are limited to small scale, expensive and complicated chemical vapor deposition (CVD) for CNT synthesis. We present a new method for direct growth of CNTs on one or both sides of a thin graphene film (GF) using joule self-heating of the graphene film to provide the necessary heat for the thermal breakdown of carbon feedstock in a CVD process. The resulting CNT forests show good density and alignment consistent with regular CVD synthesis processes on silicon surfaces. The resulting double sided GF/CNT hybrid film is directly applicable as a thermal pad. The CNT forest has a thermal conductivity of 30 W/mK, measured by pulsed photothermal reflectance, and the total thermal interface resistance between aluminum blocks was measured to be 60 Kmm 2 /W using an ASTM D5470 compliant 1-D measurement setup. This method of directly synthesizing CNTs on graphene films is more energy efficient and capable of larger volume production compared to traditional CVD methods. It is also compatible with scaling up towards continuous roll-to-roll production for large scale commercial production, one of the major limitations preventing CVD-grown CNTs from commercial applications
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| 43. |
- Hill, Sandra Malmgren, 1987, et al.
(författare)
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Asymmetric Inheritance of Aggregated Proteins and Age Reset in Yeast Are Regulated by Vac17-Dependent Vacuolar Functions
- 2016
-
Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 16:3, s. 826-838
-
Tidskriftsartikel (refereegranskat)abstract
- Age can be reset during mitosis in both yeast and stem cells to generate a young daughter cell from an aged and deteriorated one. This phenomenon requires asymmetry-generating genes (AGGs) that govern the asymmetrical inheritance of aggregated proteins. Using a genome-wide imaging screen to identify AGGs in Saccharomyces cerevisiae, we discovered a previously unknown role for endocytosis, vacuole fusion, and the myosin-dependent adaptor protein Vac17 in asymmetrical inheritance of misfolded proteins. Overproduction of Vac17 increases deposition of aggregates into cytoprotective vacuole-associated sites, counteracts age-related breakdown of endocytosis and vacuole integrity, and extends replicative lifespan. The link between damage asymmetry and vesicle trafficking can be explained by a direct interaction between aggregates and vesicles. We also show that the protein disaggregase Hsp104 interacts physically with endocytic vesicle-associated proteins, such as the dynamin-like protein, Vps1, which was also shown to be required for Vac17-dependent sequestration of protein aggregates. These data demonstrate that two physiognomies of aging-reduced endocytosis and protein aggregation-are interconnected and regulated by Vac17.
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| 44. |
- Huang, S., et al.
(författare)
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Improved reliability of electrically conductive adhesives joints on Cu-Plated PCB substrate enhanced by graphene protection barrier
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 143-146
-
Konferensbidrag (refereegranskat)abstract
- Graphene protection barrier was introduced to the interface between the ECAs and Cu-plated wire to enhance the reliability of the ECAs joints on Cu-Plated PCB substrate due to its excellent properties of impermeability to all gases/salts as well as its thermal/chemical stability. The results of shear test indicated graphene protection barrier can improve the shear strength of the ECAs joints on Cu-plated PCB substrate by almost 22% after 500 hours high temperature and high humidity cyclic test. Characterizations by optical microscope and XPS were further performed to explain the mechanism. To sum up, it can be believed that the graphene protection barrier can dramatically enhance the reliability of the ECAs joints on Cu-Plated PCB substrate.
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| 45. |
- Huang, Shirong, et al.
(författare)
-
Infrared Emissivity Measurement for Vertically Aligned Multiwall Carbon Nanotubes (CNTs) Based Heat Spreader Applied in High Power Electronics Packaging
- 2016
-
Ingår i: 6th Electronic System-integration Technology Conference (ESTC 2016). - 9781509014026 ; , s. Article no 7764696-
-
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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| 46. |
- Huang, Shirong, et al.
(författare)
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Reliability of Graphene-based Films Used for High Power Electronics Packaging
- 2015
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Ingår i: 16th International Conference on Electronic Packaging Technology, ICEPT 2015, Changsha, China, 11-14 August 2015. - 9781467379991 ; , s. 852-855
-
Konferensbidrag (refereegranskat)abstract
- Graphene-base film was fabricated with chemical conversion process, including graphene oxide (GO) prepared by Hummer's method, graphene oxide reduced with L-ascorbic acid (LAA), graphene based film deposited by vacuum filtration process. Meanwhile, the functionalization of the graphene-based film was performed to decrease the thermal interface resistance between the graphene-based film and substrate. Characterization data showed that the graphene-based film possessed high reliability after 500 hours under 85°C aging test. In summary, the graphene-based film can be a promising solution in thermal management of high power electronics.
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| 47. |
- Huang, Shirong, et al.
(författare)
-
The Effects of Graphene-Based Films as Heat Spreaders for Thermal Management in Electronic Packaging
- 2016
-
Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016. - 9781509013968 ; , s. Art no 7583272; Pages 889-892
-
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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| 48. |
- Janeczek, K., et al.
(författare)
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Investigation of thermal interface materials reinforced with micro- and nanoparticles
- 2017
-
Ingår i: China Semiconductor Technology International Conference 2017, CSTIC 2017. - 9781509066940
-
Konferensbidrag (refereegranskat)abstract
- Heat management is one of the major challenges in modern electronic devices. The higher performance results in a production of greater amount of heat which needs to be efficiently dissipated so as to ensure the electronic devices operational during the period of lifetime. This paper discusses the application of micro- and nano-materials in thermal interface materials (TIM) used for heat management. Effects of type, size and geometry of different fillers were experimentally investigated. The results showed that it is recommended to utilize silver particles compared to copper ones to achieve higher heat dissipation. And the particles of smaller size may enhance the thermal conductivity of elaborated materials.
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| 49. |
- Jeong, Seung Hee, et al.
(författare)
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Mechanically Stretchable and Electrically Insulating Thermal Elastomer Composite by Liquid Alloy Droplet Embedment
- 2015
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Stretchable electronics and soft robotics have shown unsurpassed features, inheriting remarkable functions from stretchable and soft materials. Electrically conductive and mechanically stretchable materials based on composites have been widely studied for stretchable electronics as electrical conductors using various combinations of materials. However, thermally tunable and stretchable materials, which have high potential in soft and stretchable thermal devices as interface or packaging materials, have not been sufficiently studied. Here, a mechanically stretchable and electrically insulating thermal elastomer composite is demonstrated, which can be easily processed for device fabrication. A liquid alloy is embedded as liquid droplet fillers in an elastomer matrix to achieve softness and stretchability. This new elastomer composite is expected useful to enhance thermal response or efficiency of soft and stretchable thermal devices or systems. The thermal elastomer composites demonstrate advantages such as thermal interface and packaging layers with thermal shrink films in transient and steady-state cases and a stretchable temperature sensor.
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| 50. |
- Jeong, Seung Hee, 1978-, et al.
(författare)
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Stretchable Thermoelectric Generators Metallized with Liquid Alloy
- 2017
-
Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 9:18, s. 15791-15797
-
Tidskriftsartikel (refereegranskat)abstract
- Conventional thermoelectric generators (TEGs) are normally hard, rigid, and flat. However, most objects have curvy surfaces, which require soft and even stretchable TEGs for maximizing efficiency of thermal energy harvesting. Here, soft and stretchable TEGs using conventional rigid Bi2Te3 pellets metallized with a liquid alloy is reported. The fabrication is implemented by means of a tailored layer-by-layer fabrication process. The STEGs exhibit an output power density of 40.6 ?W/cm2 at room temperature. The STEGs are operational after being mechanically stretched-and-released more than 1000 times, thanks to the compliant contact between the liquid alloy interconnects and the rigid pellets. The demonstrated interconnect scheme will provide a new route to the development of soft and stretchable energy-harvesting avenues for a variety of emerging electronic applications.
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