| 501. |
- Zhang, Xia, 1980, et al.
(författare)
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Flip chip assembly using carbon nanotube bumps and anisotropic conductive adhesive film
- 2010
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Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781607682639 ; 27:1, s. 825-830
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Konferensbidrag (refereegranskat)abstract
- Carbon Nanotube (CNT) has been proposed as a promising candidate material to build next generation flip chip interconnects in electronics. In this paper, flip chip assembly using CNT bumps and ACF is performed. To realize CNT-based interconnects, post-growth processes including deposition of metallic layers on CNT bundles and low temperature transfer of CNT bundles have been developed to overcome the problems of the high growth temperature of CNT as well as the poor adhesion between CNT bumps and substrates. Moreover, ACF has been used to assemble the CNT bumps on another Si substrate. The electrical test is performed also to verify the good contact between CNT bumps and ACF.
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| 502. |
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| 503. |
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| 504. |
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| 505. |
- Zhang, Yong, 1982, et al.
(författare)
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2D HEAT DISSIPATION MATERIALS FOR MICROELECTRONICS COOLING APPLICATIONS
- 2016
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Ingår i: China Semiconductor Technology International Conference 2016, CSTIC 2016. - 9781467388047
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Konferensbidrag (refereegranskat)abstract
- The need for faster and smaller, as well as more reliable and efficient consumer electronic products has resulted in microelectronic components that produce progressively more heat. The resultant reliability issues from the increased heat flux are serious and hinder technological development. One solution for microelectronics cooling applications is 2D materials applied as heat spreaders and these include monolayer graphene, graphene based films, and monolayer hexagonal boron nitride and BN based films. In addition, thermal performances of the graphene heat spreader were also studied under different packaging structures, including wire bonding, cooling fins and flip chips. Finally, 2D hexagonal Boron nitride (h-BN) heat spreaders, fabricated by different methods, had their heat dissipation performances characterized by different thermal characterization methods, such as resistance temperature detector (RTD) and Infrared (IR) methods. In conclusion, these new novel 2D materials developed show great potential for microelectronics cooling applications.
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| 506. |
- Zhang, Yong, 1982, et al.
(författare)
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Characterization and simulation of liquid phase exfoliated graphene-based films for heat spreading applications
- 2016
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 106, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- This paper concerns the thermal properties of graphene-based films for heat spreading applications. Following liquid phase exfoliation (LPE) films were made by two different methods, vacuum filtration and drop coating. Temperature decreases of up to 6 °C and 4 °C were measured at a heat flux density of 1200 W/cm2 for the vacuum filtrated and drop coated films respectively. For the first time in this paper, three different methods were combined to evaluate and predict the thermal performance of such graphene-based films. Resistance thermometers were used to monitor the hotspot temperature decrease versus the Joule heat flow as a result of using graphene-based heat spreaders. The 3ω method was used to experimentally determine the in-plane and through-plane thermal conductivities of such films. A finite element model of the hotspot test structure was setup using the in-plane and through-plane thermal conductivities (110 and 0.25 W/mK, respectively) obtained from the 3ω measurements. Simulations were performed to predict the hotspot temperature decrease with excellent agreement obtained between all methods. The results indicate that the alignment and purity of the graphene-based films, as well as their thermal boundary resistance with respect to the chip, are key parameters when determining the thermal performance of graphene-based heat spreaders.
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| 507. |
- Zhang, Y., et al.
(författare)
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Characterization of nano-enhanced interconnect materials for fine pitch assembly
- 2014
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Ingår i: Soldering and Surface Mount Technology. - : Emerald. - 1758-6836 .- 0954-0911. ; 26:1, s. 12-17
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - Multiple fillers are adopted to study the filler influences on electrical and mechanical properties of the conductive adhesives. The performances of the developed nano-enhanced interconnect materials in printing process are also evaluated. The paper aims to discuss these issues. Design/methodology/approach - Micron-sized silver flakes are used as the basic fillers, and submicro- and nano-sized silver spheres and carbon nanotubes (CNTs) are adopted to obtain conductive adhesives with multiple fillers. Differential scanning calorimetry measurement is carried out to characterize the curing behavior of the samples with different fillers, four-probe method is used to obtain the bulk resistivity, shear test is conducted for adhesive strength, and environmental loading test is also involved. Furthermore, printing trials with different patterns have been carried out. Findings -The electrical resistivity of the adhesives with submicro-sized silver spheres does not monotonically change with the increasing sphere proportion, and there exists an optimized value for the ratio of silver flakes to spheres. Samples with relatively small amount of CNT additives show improved electrical properties, while their mechanical strengths tend to decrease. For the printing application, the adhesives with 18.3 volume% filler content behave much better than those with lower filler content of 6 percent. The presence of the nano-particles makes a slight improvement in the printing results. Research limitations/implications - More detailed printing performance and reliability test of the samples need to be carried out in the future. Originality/value - The conductive adhesives as interconnect materials exhibit some improved properties with optimized bimodal or trimodal fillers. The additive of the nano-fillers affects slightly on the printing quality of the bimodal conductive adhesives.
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| 508. |
- Zhang, Yong, 1982, et al.
(författare)
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Chemical vapor deposition grown graphene on Cu-Pt alloys
- 2017
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Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 193, s. 255-258
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, the results from a series of experiments where graphene was grown on copper-platinum (Cu-Pt) alloy foils by chemical vapor deposition (CVD) are presented. By using Raman spectroscopy to analyze graphene films grown on Pt-Cu alloy foils with different Cu/Pt weight ratios (75/25, 50/50 and 25/75), we could show how the Cu/Pt weight ratio affected both the quality and the number of layers in the as-synthesized graphene films. Furthermore, graphene growth was shown to occur at temperatures as low as 750 °C due to what we believe is the strong catalytic ability of the Cu-Pt alloy foils. By keeping the flow rate of the CH4 precursor gas as low as 1.5 sccm, a low growth rate was obtained where the growth rates of monolayer and bilayer graphene could be controlled by simply adjusting the growth time.
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| 509. |
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| 510. |
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