| 61. |
- Li, X., et al.
(author)
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Reliability of Carbon Nanotube Bumps for Chip on Film Application
- 2013
-
In: Proceedings of the IEEE Conference on Nanotechnology. - 1944-9399 .- 1944-9380. - 9781479906758 ; , s. 845-848
-
Conference paper (peer-reviewed)abstract
- Carbon nanotubes (CNTs) are an ideal candidate for electrical interconnects due to their extraordinary thermal, electrical and mechanical properties. In this work, as-densified CNT bumps were applied as chip on film (COF) interconnection material. A silicon chip with patterned CNT bumps was bonded onto a flexible substrate using anisotropic conductive adhesive (ACA) with bonding pressure, at 127.4 MPa, 170 °C and for 8 seconds. The electrical properties of this structure were evaluated by measuring the contact resistance of each bump using the four-point probe method. Thermal cycling (-40∼85°C, 1000 cycles) and damp heat tests (85°C/85% RH, 1000 hours) were conducted to evaluate the reliabilities of the CNT-COF structure bonded with ACA. The average contact resistances of two samples used for the reliability tests were 226 mΩ and 260mΩ. No electrical failure was observed after the damp heat test and only two were observed after the thermal cycling test. The average contact resistance was increased only 15.7% and 13.8%, respectively, after the thermal cycling and the damp heat tests. © 2013 IEEE.
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| 62. |
- Liu, Johan, 1960, et al.
(author)
-
1. Thermal Characterization of Power Devices Using Graphene-based Film
- 2014
-
In: Proceedings - Electronic Components and Technology Conference. - 0569-5503. - 9781479924073 ; , s. 459 - 463
-
Conference paper (peer-reviewed)abstract
- Due to its atomic structure with sp2 hybrid orbitals and unique electronic properties, graphene has an extraordinarily high thermal conductivity which has been reported to be up to 5000 W/mK. As a consequence, the use of graphene-based materials for thermal management has been subject to substantial attention during recent years in both academia and industry. In this paper, the development of a new type of graphene-based thin film for heat dissipation in power devices is presented. The surface of the developed graphene based film is primarily composed of functionalized graphene oxide, that can be bonded chemically to the device surface and thus minimize the interface thermal resistance caused by surface roughness. A very high in-plane thermal conductivity with a maximum value of 1600 W/mK was detected by laser flash machine regarding to the graphene-based films. To investigate the structure of the graphene-based films, scanning electron microscopy (SEM) and raman spectroscopy were carried out. Finally, LED demonstrators were built to illustrate the thermal performance of graphene-based film and the functional layers. IR camera recorded a 5°C lower temperature of a LED demonstrator with SHT G1000 as the binding layer instead of a commercial thermal conductive adhesive.
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| 63. |
- Liu, Johan, 1960, et al.
(author)
-
A new solder matrix nano polymer composite for thermal management and die attach applications
- 2014
-
In: Composites Science and Technology. - 0266-3538. ; 94, s. 54-61
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Journal article (peer-reviewed)abstract
- The increasing integration of microelectronics, raising the need for effective heat dissipation, requires new and improved composite materials technologies. For both thermal interface and die attach materials, a major challenge is to combine low thermal resistance joints with sufficient thermomechanical decoupling and reliability. In this paper, we present the fabrication and characterisation of a new type of solder matrix nano polymer composite (SMNPC) aiming to address these challenges. The SMNPC is fabricated into preforms by liquid-phase infiltration of a Sn–Ag–Cu matrix into a silver nanoparticle coated electrospun polyimide fibre mesh. The composite is demonstrated to possess high heat transfer capability, close to that of a direct soldered interface, lower elastic modulus compared to pure Sn–Ag–Cu alloy, and reliable thermomechanical performance during thermal cycling. Taken together, the results indicate that the developed SMNPC can be a useful composite alternative compared to conventional solders and polymer matrix materials for thermal management applications.
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| 64. |
- Liu, Johan, 1960, et al.
(author)
-
Carbon Nanotubes for Electronics Manufacturing and Packaging: From Growth to Integration
- 2013
-
In: Advances in Manufacturing. - : Springer Science and Business Media LLC. - 2095-3127 .- 2195-3597. ; 1:1, s. 13-27
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Research review (peer-reviewed)abstract
- Carbon nanotubes (CNTs) possess excellent electrical, thermal and mechanical properties. They are light in weight yet stronger than most of the other materials. They can be made both highly conductive and semi-conductive. They can be made from nano-sized small catalyst particles and extend to tens of millimeters long. Since CNTs emerged as a hot topic in the early 1990s, numerous research efforts have been spent on the study of the various properties of this new material. CNTs have been proposed as alternative materials of potential excellence in a lot of applications such as electronics, chemical sensors, mechanical sensors/actuators and composite materials, etc. This paper reviews the use of CNTs particularly in electronics manufacturing and packaging field. The progresses of three most important applications, including CNT-based thermal interface materials, CNT-based interconnections and CNT-based cooling devices are reviewed. The growth and post-growth processing of CNTs for specific applications are introduced and the tailoring of CNTs properties, i.e., electrical resistivity, thermal conductivity and strength, etc., is discussed with regard to specific application requirement. As the semiconductor industry is still driven by the need of getting smaller and faster, CNTs and the related composite systems as emerging new materials are likely to provide the solution to the future challenges as we make more and more complex electronics devices and systems.
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| 65. |
- Liu, Johan, 1960, et al.
(author)
-
CHEMICALLY VAPOR DEPOSITED CARBON NANOTUBES FOR VERTICAL ELECTRONICS INTERCONNECT IN PACKAGING APPLICATIONS
- 2014
-
In: Proceedings of the 12th international conference on Solid States and Integrated Circuits, ICSICT2014. - 9781479932962 ; , s. 47-50
-
Conference paper (peer-reviewed)abstract
- Carbon Nanotubes (CNTs) have excellent electrical, thermal and mechanical properties. They are mechanically strong at nanoscale yet also flexible if made micro- or milli-meter long. They are synthesized from nano-sized catalyst particles and can be made up to millimeters. A lot of research studies have been spent on various properties of the CNTs. They are regarded as an alternative material in a lot of applications such as ICs, MEMS, sensors, biomedical and other composite materials, etc. Among them, the thermally grown CNTs using chemical vapor deposition method is of particular interested in electronics applications as an interconnect material. This paper reviews the use of CNTs as an interconnect material for packaging applications. The growth and post-growth processing of CNTs are covered and the tailoring of CNTs properties, i.e. electrical resistivity, thermal conductivity and strength, etc., is discussed. To make the electronics systems smaller, faster and more power efficient, CNTs as a potential new material are likely to provide the solution to the future challenges as the electronics systems are getting more and more functional and complex nowadays.
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| 66. |
- Liu, Johan, 1960, et al.
(author)
-
Development and Characterization of Nano-Composite Solder
- 2012
-
In: Lead-Free Solders: Materials Reliability for Electronics. - Chichester, UK : John Wiley & Sons, Ltd. - 9781119966203 ; , s. 161-177
-
Book chapter (other academic/artistic)abstract
- © 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd. Lead-free solder and its soldering processing has been well developed and applied in the electronics industry as an interconnection material to replace Sn37Pb solder. However, in recent years with the rapid development of high-density, thin and 3D packaging technology, disadvantages of lead-free solder, such as high soldering processing temperature, which can result in unstable microstructure and thermal stress build-up, have been gradually exposed, limiting its application. Therefore, nanocomposite solder, as a possible replacement for traditional lead-free solder, has been developed and studied for the past decade. The purpose of this chapter is to present the development status and achievements of nanocomposite solder. It will first describe two kinds of fabrication processing of nanoreinforcement and nanocomposite solder. It will then summarize the type of nanocomposite solder and categorize it based on different kinds of nanoreinforcement. Finally, the influences of nanoreinforcement on microstructure, its physical properties and mechanical properties on solder are illustrated in detail and analyzed. In addition, theory and the studies on how nanoreinforcements work on the enhancement of solder performances are also mentioned in this chapter.
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| 67. |
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| 68. |
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| 69. |
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| 70. |
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