| 51. |
- Wang, Teng, 1983, et al.
(författare)
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Development of Carbon Nanotube Bumps for Ultra Fine Pitch Flip Chip Interconnection
- 2006
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Ingår i: 1st Electronics Systemintegration Technology Conference; Dresden, Saxony; Germany; 5 September 2006 through 7 September 2006. - 9781424405527 ; 2, s. 892-895
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Konferensbidrag (refereegranskat)abstract
- Since 1991, carbon nanotubes have been considered for successful applications in various fields due to their unique properties. In the present work, carbon nanotubes are applied in integrated circuit packaging, as the bump interconnection for flip chip. The reason for choosing carbon nanotubes as the bump material is their special electrical, mechanical and thermal properties, which may promote both the performance and reliability of the flip chip packaging. Moreover, carbon nanotubes can be formed according to a precisely predefined small-scale pattern, which makes extremely high density interconnection possible. Vertically aligned carbon nanotubes are grown on silicon in the form of square arrays of different sizes, heights and pitches. Attempts to use thermal compression and anisotropic conductive adhesive to bond chips carrying carbon nanotube bumps with ceramic substrates are also executed. Mechanical testing is performed afterward to determine the strength of the bonding interfaces. The strength of the bonding by thermal compression is very weak, in the range from 1.9 to 7.0 g/mm2. The bonding by anisotropic conductive adhesive is much stronger, indicating a possible approach to bond chips carrying carbon nanotube bumps.
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| 52. |
- Wang, Teng, 1983, et al.
(författare)
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Low temperature transfer and formation of carbon nanotube arrays by imprinted conductive adhesive
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:9
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Tidskriftsartikel (refereegranskat)abstract
- This letter demonstrates the transfer and formation of aligned carbon nanotube (CNT) arrays at low temperature by imprinted conductive adhesive. A thermoplastic isotropic conductive adhesive is patterned by an imprint and heat transfer process. The CNTs grown by thermal chemical vapor deposition are then transferred to another substrate by the conductive adhesive, forming predefined patterns. The current-voltage response of the transferred CNT bundles verifies that good electrical connection has been established. This process can enable the integration of CNTs into various temperature-sensitive processeses and materials.
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| 53. |
- 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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| 54. |
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| 55. |
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| 56. |
- Zhang, Dongsheng, et al.
(författare)
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Thermal properties of TIM using CNTs forest in electronics packaging
- 2016
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Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016; Wuhan Optics Valley Kingdom Hotel Wuhan; China; 16 August 2016 through 19 August 2016. ; , s. 1355-1359
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Konferensbidrag (refereegranskat)abstract
- Thermal interface material (TIM) is applied to fill the air gaps of interfaces, which provides a path for interfacial heat transfer. Owing to the exceptional thermal properties of carbon nanotubes (CNT), TIMs based on CNTs have received much attention in recent years. In this study, heat dissipation performance of vertically aligned carbon nanotubes (VACNT) arrays as TIM in electronic packing was analyzed. Vertically aligned carbon nanotubes with length of 245?m and 763?m were synthesized on a silicon substrate by chemical vapor deposition respectively. Morphology of the vertically aligned carbon nanotubes was characterized by scanning electron microscope. The hotspot temperature of thermal test chip with vertically aligned carbon nanotubes were characterized by resistance temperature detector method and infrared imaging method.
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| 57. |
- Zhang, Maomao, et al.
(författare)
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Effect of pressure during graphitization on mechanical properties of graphene films
- 2019
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Ingår i: 2019 20th International Conference on Electronic Packaging Technology, ICEPT 2019.
-
Konferensbidrag (refereegranskat)abstract
- Graphene films (GFs) can be used in the field of electronics cooling, owing to many outstanding properties. In the present paper, GFs samples were graphitized at different pressures to study their effect on the mechanical properties. The elastic modulus and hardness of GFs were measured by nanoindentation and the tensile strength of GFs were obtained by stretching GFs in a tensile tester. Meanwhile, GFs were characterized by X-ray diffraction(XRD), Scanning electron microscopy (SEM) and Raman spectroscopy. The results show that the modulus, hardness and tensile strength of GFs were strongly influenced by the defect and wrinkles among other things.
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| 58. |
- Zhang, Q., et al.
(författare)
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Effect of sintering method on properties of nanosilver paste
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. ; , s. 186-189
-
Konferensbidrag (refereegranskat)abstract
- Nanoscale silver paste has a good application prospect in heat dissipation of high-power chips due to the characteristics of low temperature sintering and high temperature service. The properties of the nanosilver paste including thermal conductivity, electrical conductivity, and shear strength are affected greatly by the sintering process. The influence of different sintering methods on the performance of the nanosilver paste was studied in this article. The nanosilver paste with 80.5 wt% nano-scale silver particles, 1.5 wt% submicron-scale SiC particles with Ag coating, 0.9 wt% dispersion agent, 10 wt% organic carrier and 7.1 wt% diluting agent was sintered at 260°C for 30 min with three different methods, heating table sintering, heating furnace sintering, and mixed sintering. The samples obtained by mixed sintering process have higher thermal conductivity than the ones obtained by heating furnace sintering method and heating table sintering method. The effect of sintering methods on shear strength of nanosilver paste was also investigated subsequently. Shear testing equipment was used to measure the shear strength of the samples gained by heating table sintering, heating furnace sintering, and air dry oven sintering. The maximum shear strength was obtained for the samples by heating table sintering method. The shear strength of samples by air dry oven sintering method was the minimum one.
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| 59. |
- Zhang, Q., et al.
(författare)
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Mechanical property and reliability of bimodal nano-silver paste with Ag-coated SiC particles
- 2019
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Ingår i: Soldering and Surface Mount Technology. - 1758-6836 .- 0954-0911. ; 31:4, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, Emerald Publishing Limited. Purpose: This study aims to develop a bimodal nano-silver paste with improved mechanical property and reliability. Silicon carbide (SiC) particles coated with Ag were introduced in nano-silver paste to improve bonding strength between SiC and Ag particles and enhance high-temperature stability of bimodal nano-silver paste. The effect of sintering parameters such as sintering temperature, sintering time and the proportion of SiC particles on mechanical property and reliability of sintered bimodal nano-silver structure were investigated. Design/methodology/approach: Sandwich structures consist of dummy chips and copper substrates with nickel and silver coating bonded by nano-silver paste were designed for shear testing. Shear strength testing was conducted to study the influence of SiC particles proportions on the mechanical property of sintered nano-silver joints. The reliability of the bimodal nano-silver paste was evaluated experimentally by means of shear test for samples subjected to thermal aging test at 150°C and humidity and temperature testing at 85°C and 85 per cent RH, respectively. Findings: Shear strength was enhanced obviously with the increase of sintering temperature and sintering time. The maximum shear strength was achieved for nano-silver paste sintered at 260°C for 10 min. There was a negative correlation between the proportion of SiC particles and shear strength. After thermal aging testing and humidity and temperature testing for 240 h, the shear strength decreased a little. High-temperature stability and high-hydrothermal stability were improved by the addition of SiC particles. Originality/value: Submicron-scale SiC particles coated with Ag were used as alternative materials to replace part of nano-silver particles to prepare bimodal nano-silver paste due to its high thermal conductivity and excellent mechanical property.
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| 60. |
- Zhang, Xia, 1980, et al.
(författare)
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Design of Printed Monopole Antennas on Liquid Crystal Polymer Substrates
- 2010
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Ingår i: Journal of Infrared, Millimeter, and Terahertz Waves. - : Springer Science and Business Media LLC. - 1866-6892 .- 1866-6906. ; 31:4, s. 469-480
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a compact printed monopole antenna with an extremely wide bandwidth has been realized on Liquid Crystal Polymer (LCP) substrates by using standard processing technology. Both laminated and directed metalized LCP substrates were used in this experiment. The antenna made on the direct metalized LCP substrate performed well compared to on the laminated LCP substrate. To improve the adhesion, the surface of the LCP was further roughened and a certain adhesion layer was used prior to the deposition of Cu. The measured antenna on a metalized LCP substrate could cover this frequency band with an impedance bandwidth from 0.51 GHz to 14.4 GHz (28.2:1) for VSWRa parts per thousand currency sign2. Moreover, the antenna exhibits a nearly omni-directional radiation pattern. The size of this antenna is only about 0.18 lambda(1) x 0.13 lambda(1), where lambda(1) is the wavelength of the lowest operating frequency. The results show that LCP is a promising candidate for high frequency applications.
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