| 1. |
- Bao, Jie, et al.
(författare)
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Application of two-dimensional layered hexagonal boron nitride in chip cooling
- 2016
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Ingår i: Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and Engineering. - 1005-0930. ; 24:1, s. 210-217
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Tidskriftsartikel (refereegranskat)abstract
- © 2016, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.Research into layered hexagonal boron nitride(h-BN)has recently intensified, due to its superior physicochemical properties compared to that of a typical two-dimensional material. H-BN can be utilized in power chips as both an insulating layer as well as a heat spreader for local hotspots with high heat flux. Single layer h-BN film grown by CVD and h-BN microparticles are respectively transferred onto the surfaces of the thermal evaluation chips, where the influence of h-BN on the heat dissipation performance of the chips can be observed at different power values. The resistance-temperature curve method and infrared thermal imager are both used to measure the temperature of hotspots on the thermal evaluation chips, which can be reduced by between 3~5℃ at 1W after the transfer of h-BN. The cooling efficiency is improved and it can be found that single layer h-BN film shows better heat dissipation ability.
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| 2. |
- Daon, J., et al.
(författare)
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Chemically enhanced carbon nanotubes based Thermal Interface Materials
- 2015
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Ingår i: THERMINIC 2015 - 21st International Workshop on Thermal Investigations of ICs and Systems 2015. - 9781467397056
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Konferensbidrag (refereegranskat)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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| 3. |
- Daon, J., et al.
(författare)
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Electrically conductive thermal interface materials based on vertically aligned carbon nanotubes mats
- 2014
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Ingår i: 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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Konferensbidrag (refereegranskat)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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| 4. |
- Fu, Yifeng, 1984, et al.
(författare)
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Carbon nanotube growth on different underlayers for thermal interface material application
- 2016
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Ingår i: IMAPS Nordic Annual Conference 2016 Proceedings. - 9781510827226
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Konferensbidrag (refereegranskat)abstract
- Thermal interface material (TIM) is a critical component in thermal management of high density packaging systems since both the reliability and lifetime of microsystems are dependent on how the heat is dissipated. Carbon nanotubes (CNTs) are promising candidate for development of TIMs due to their excellent thermal and mechanical properties. The thermal conductivity of CNTs can be up to 3000 W/mK in the longitudinal direction which acts as ideal heat transfer path. However, the huge interfacial thermal resistance between CNTs and contact surface hinders the exploitation of CNTs as TIMs. In this paper, we will focus on the growth of CNTs on various substrates and underlayers and analyze the interaction between catalyst and underlayer materials. Microscopic analysis is performed to characterize the quality of the CNT materials and monitor the diffusion of Fe particles into different barrier layers. Thermal conductivity of the CNT TIMs will be measured to examine the performance of the materials.
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| 5. |
- Fu, Yifeng, 1984, et al.
(författare)
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Post-Growth Processing of Carbon Nanotubes for Interconnect Applications - A Review
- 2016
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Ingår i: 2016 6th Electronic System-Integration Technology Conference (Estc). - 9781509014026 ; , s. Article no 7764713-
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Konferensbidrag (refereegranskat)abstract
- Interconnect is one of the most important functions of packaging technology. It delivers power and signals into and out of electronic systems. The performance and reliability of microsystems are dependent on the interconnect quality. This paper reviews the chip-level interconnects based on carbon nanotubes (CNTs), this includes their applications for both on-chip and off-chip interconnects. Various post-growth processing of CNTs, such as doping, densification, transfer, metallization, etc., for the improvement of their performance will be reviewed.
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| 6. |
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| 7. |
- Huang, Shirong, et al.
(författare)
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Graphene Based Heat Spreader for High Power Chip Cooling Using Flip-chip Technology
- 2013
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Ingår i: 2013 IEEE 15th Electronics Packaging Technology Conference (EPTC 2013). - 9781479928330 ; , s. 347-352
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Konferensbidrag (refereegranskat)abstract
- Monolayer graphene was synthesized through thermal chemical vapor deposition (TCVD) as heat spreader for chip cooling. Platinum (Pt) serpentine functioned as hot spot on the thermal testing chip. The thermal testing chip with monolayer graphene film attached was bonded using flip-chip technology. The temperature at the hot spot with a monolayer graphene film as heat spreader was decreased by about 12°C and had a more uniform temperature compared to those without graphene heat spreader when driven by a heat flux of about 640W/cm 2 . Further improvements to the cooling performance of graphene heat spreader could be made by optimizing the synthesis parameters and transfer process of graphene films. © 2013 IEEE.
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| 8. |
- 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. ; , 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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| 9. |
- Jiang, Di, 1983, et al.
(författare)
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A flexible and stackable 3D interconnect system using growth-engineered carbon nanotube scaffolds
- 2017
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Ingår i: Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 2:2
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Tidskriftsartikel (refereegranskat)abstract
- One of the critical challenges for realizing flexible electronic systems for a wide range of applications is the development of materials for flexible and stackable interconnects. We propose and demonstrate a three-dimensional (3D)interconnect structure embedded in a polymeric substrate using metal-coated carbon nanotube (CNT)scaffolds. By using two different underlayer materials for the catalyst, onestep synthesis of a dual-height CNT interconnect scaffold was realized. The CNT scaffolds serve as flexible cores for both annular metal through-substrate-vias and for horizontal metal interconnect. The 3D-CNT network was fabricated on a silicon substrate, and once the scaffolds were covered by metal, they were embedded in a polymer serving as a flexible substrate after peel-off from the silicon substrate. The 3D-CNT interconnect network was exposed to mechanical bending and stretching tests while monitoring its electrical properties. Even after 300 cycles no significant increase of resistances was found. Electrically there is a trade-off between flexibility and conductivity due to the surface roughness of the scaffold. However, this is to some extent alleviated by the metalized sidewalls giving the horizontal wires a cross-sectional area larger than indicated by their footprint. For gold wires 200 nm thick, measurements indicated a resistivity of 18 μΩ.cm, a value less than one order of magnitude larger than that of bulk gold, and a value that is expected to improve as technology improves. The mechanical properties of the metalized scaffolds were simulated using a finite element model. The potential scale-up capability of the proposed 3D-CNT network was demonstrated by the stacking of two such polymer-embedded interconnect systems.
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| 10. |
- Jiang, Di, 1983, et al.
(författare)
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Carbon nanotube/solder hybrid structure for interconnect applications
- 2014
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Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962751-
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Konferensbidrag (refereegranskat)abstract
- A carbon nanotube (CNT)/Solder hybrid bump structure is proposed in this work in order to overcome the drawbacks of high CNT resistivity while retaining the advantages of CNTs in terms of interconnect reliability. Lithographically defined hollow CNT moulds are grown by thermal chemical vapor deposition (TCVD). The space inside the CNT moulds is filled up with Sn-Au-Cu (SAC) solder spheres of around 10 μm in diameter. This CNT/Solder hybrid material is then reflowed and transferred onto target indium coated substrate. The reflow melts the small solder spheres into large single solder balls thus forming a hybrid interconnect bump together with the surrounding densified CNT walls, which the CNT and the solder serve as resistors in parallel. The electrical resistance of such a CNT/Solder structure is measured to be around 6 folds lower than pure CNT bumps.
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