| 11. |
- Daon, J., et al.
(author)
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Chemically enhanced carbon nanotubes based Thermal Interface Materials
- 2015
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In: THERMINIC 2015 - 21st International Workshop on Thermal Investigations of ICs and Systems 2015. - 9781467397056
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Conference paper (peer-reviewed)abstract
- With progress in microelectronics the component density on a device increases drastically. As a consequence the power density reaches levels that challenge device reliability. New heat dissipation strategies are needed to efficiently drain heat. Thermal Interface Materials (TIMs) are usually used to transfer heat across interfaces, for example between a device and its packaging. Vertically Aligned Carbon Nanotubes (VACNTs) can be used to play this role. Indeed, carbon nanotubes are among the best thermal conductors (similar to 3.000 W/mK) and in the form of VACNT mats, show interesting mechanical properties. On one side, VACNTs are in contact with their growth substrate and there is a low thermal resistance. On the other side, good contact must be created between the opposite substrate and the VACNTs in order to decrease the contact thermal resistance. A thin-film deposition of an amorphous material can be used to play this role. This paper reports a chemically enhanced carbon nanotube based TIM with creation of chemical bonds between the polymer and VACNTs. We show that these covalent bonds enhance the thermal transfer from VACNTs to a copper substrate and can dramatically decrease local resistances. Implementation processes and thermal characterizations of TIMs are studied and reported.
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| 12. |
- Daon, J., et al.
(author)
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Electrically conductive thermal interface materials based on vertically aligned carbon nanotubes mats
- 2014
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In: IEEE 20th International Workshop on Thermal Investigation of ICs and Systems (Therminic). Greenwich, London, United Kingdom, 24-26 September 2014. - 9781479954155
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Conference paper (peer-reviewed)abstract
- In power microelectronics, the trends towards miniaturization and higher performances result in higher power densities and more heat to be dissipated. In most electronic assembly, thermal interface materials (TIM) help provide a path for heat dissipation but still represent a bottleneck in the total thermal resistance of the system. VA-CNTs mats are typically grown on HR silicon substrate with Al2O3 diffusion barrier layer using Thermal CVD process. In many cases, 'die attach' thermal interface materials need to be electrically conductive and the growth of dense VA-CNT mats on an electrically conductive substrate remains a challenge. This paper presents the growth of dense VA-CNT mats on doped silicon with Al2O3 and TiN diffusion barrier layer. Processes, thermal and electrical characterization of VA-CNTs based thermal interface materials are studied and reported.
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| 13. |
- Darmawan, C. C., et al.
(author)
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Graphene-CNT hybrid material as potential thermal solution in electronics applications
- 2017
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In: 2017 IMAPS Nordic Conference on Microelectronics Packaging (NordPac). - 9781538630556 ; , s. 190-193
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Conference paper (peer-reviewed)abstract
- Graphene and CNT have great potential in electronics applications. This work explored the possibility of integrating 1D CNT and 2D graphene into a 3D covalently bonded structure, i.e. a graphene-CNT hybrid material for thermal management application. The graphene-CNT hybrid material was later investigated morphologically and thermally to observe its heat dissipation capability.
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| 14. |
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| 15. |
- Enmark, Markus, 1991, et al.
(author)
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A Critical Assessment of Nano Enhanced Vapor Chamber Wick Structures for Electronics Cooling
- 2021
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In: 2021 23rd European Microelectronics and Packaging Conference and Exhibition, EMPC 2021.
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Conference paper (peer-reviewed)abstract
- The increasing need for high thermal dissipation in small electronic products puts tough requirements on effective cooling solutions. Two of the most effective passive cooling devices in electronics today are vapor chambers and heat pipes. With new advancements in materials science and nanotechnology comes the possibility to further increase cooling capacity and at the same time make devices lighter. This study is a critical assessment on recent progress in the field of nanomaterial enhanced wick structures in vapor chambers and heat pipes. In this paper, nano-enhanced wick structures are divided into five different sub-categories based on material type. Publication trends for the different types of nano-enhanced wicks are studied by plotting them on a timeline. It is found that nanostructured metal wicks is the most studied field in recent years. A plot showing wick performance in terms of superheat temperatures for given heat flux is created to be used for benchmarking of new wick structures when pool boil experiments are carried out. An attempt to find correlation between publication trends, type of wick and performance is done. On the basis of the gathered data it is deemed difficult to find a distinct correlation, this is mainly due to difficulty in comparing performance between different studies, especially when different heat fluxes are used. There is no unambiguous answer to which category of nano-enhanced wicks that should be target for future studies. Graphene coating and pure carbon nanomaterials such as aerogels and graphene foam are still relatively unexplored and believed to have great potential if they can be attached to envelope materials.
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| 16. |
- Enmark, Markus, 1991, et al.
(author)
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Reliability Characterization of Graphene Enhanced Thermal Interface Material for Electronics Cooling Applications
- 2022
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In: 2022 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2022.
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Conference paper (peer-reviewed)abstract
- Graphene-based products are gaining popularity in thermal management applications in high performance electronics systems. The ultra-high thermal conductivity of graphene together with its relatively low density makes it a suitable material for reaching high cooling capability in lightweight applications. An example of products that are starting to enter the market is graphene enhanced thermal interface materials (TIMs). Pristine graphene enhanced TIMs are well characterized and show high thermal conductivity and low thermal interface resistance. Before these TIMs can take the next step from being a niche product to reach high volume sales on the market, it needs to be proven that they have stable performance over time when conditioned and aged according to industry reliability standards. In this work, a set of customized test rigs was designed, and graphene enhanced TIMs of three different thicknesses were tested. The TIMs were compressed by 30% and then subjected to three different industry standard reliability tests; thermal aging, temperature cycling and damp heat. The thermal resistance was measured sequentially during each test to monitor change over time. The reliability tests are still ongoing and so far the tested graphene enhanced TIMs have stable performance over time with some observable trends for the different tests. At the current test time the maximum degradation in thermal resistance is 13%, measured after 511 cycles in the thermal cycling test. The used test method is deemed promising for reliability comparison and future requirement standardization on thermal pads.
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| 17. |
- Fan, X., et al.
(author)
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Reliability of carbon nanotube bumps for chip on glass application
- 2014
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In: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962753-
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Conference paper (peer-reviewed)abstract
- Carbon nanotubes (CNTs) are an ideal candidate material for electronic interconnects due to their extraordinary thermal, electrical and mechanical properties. In this study, densified CNT bumps utilizing the paper-mediated controlled method were applied as the interconnection for chip on glass (COG) applications, and the silicon chip with patterned CNT bumps was then flipped and bonded onto a glass substrate using anisotropic conductive adhesive (ACA) at a bonding pressure of 127.4 Mpa, 170°C for 8 seconds. The electrical properties of the COG were evaluated with the contact resistance of each bump measured using the four-point probe method. Three different structure traces, marked as Trace A, Trace B, and Trace C, were tested, respectively. Thermal cycling (-40 to 85°C, 800 cycles) and damp heat tests (85°C/85% RH, 1000 hours) were also conducted to evaluate the reliability of the CNT-COG structure. The average contact resistance of the samples was recorded during these tests, in which there was no obvious electrical failure observed after both the thermal cycling and damp heat tests. The results of these tests indicated that the COG has good reliability and the CNT bumps have promising potential applications in COG.
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| 18. |
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| 19. |
- Fan, Yi, et al.
(author)
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A study of fluid coolant with carbon nanotube suspension for MicroChannel coolers
- 2008
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In: 2008 International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2008; Pudong, Shanghai; China; 28 July 2008 through 31 July 2008. - 9781424427406
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Conference paper (peer-reviewed)abstract
- In this work, silicon microchannel coolers were made using the Deep Ion Reactive Etching (DIRE) technique. Stable and homogeneous Carbon NanoTube (CNT) suspension was also prepared. Meanwhile, a closed-loop cooling test system was developed to investigate the heat removal of the silicon microchannel cooler with different coolants. The experimental setup included a test module, a minipump for providing controllable flow, and a fan system for cooling the circular fluid. Beside the inlet and outlet of the test module, two thermocouples and pressure gauges were set up to measure the temperature and pressure of the fluids. The heat removal of the silicon microchannel cooler using different CNT volume fraction of suspension coolant was studied. The results show that the microchannel cooler with CNT suspension as coolant could strengthen the heat removal capability of microchannel cooler. In addition to heat transfer enhancement, the microchannel cooler with CNT suspension coolant did not produce extra pressure drop in the present study.
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| 20. |
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