| 1. |
- Chen, S., et al.
(författare)
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An overview of carbon nanotubes based interconnects for microelectronic packaging
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 113-119
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Konferensbidrag (refereegranskat)abstract
- Owing to the great demand in more functions and miniaturization in microelectronic packaging, the dimensions of interconnects has decreased extremely, which has resulted in electrical, thermal, and mechanical reliability issues. To address these issues, carbon nanotube (CNT) has been selected as a promising alternative material for the interconnects in packaging due to its large current density, high thermal conductivity, great flexibility, and low coefficient of thermal expansion (CTE). In this paper, the development of CNTs based vertical interconnects was reviewed. However, the resistivity of CNTs based interconnects was much higher than that of copper interconnects. Thus, this review focused on the resistivity of CNTs-based interconnects in different fabrication process and pointed out what improves the resistivity. In the future, CNTs-Cu nanocomposite with unique properties could be the suitable material for bumps to reduce the resistivity of CNTs based bumps further.
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| 2. |
- Huang, S., et al.
(författare)
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Improved reliability of electrically conductive adhesives joints on Cu-Plated PCB substrate enhanced by graphene protection barrier
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 143-146
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Konferensbidrag (refereegranskat)abstract
- Graphene protection barrier was introduced to the interface between the ECAs and Cu-plated wire to enhance the reliability of the ECAs joints on Cu-Plated PCB substrate due to its excellent properties of impermeability to all gases/salts as well as its thermal/chemical stability. The results of shear test indicated graphene protection barrier can improve the shear strength of the ECAs joints on Cu-plated PCB substrate by almost 22% after 500 hours high temperature and high humidity cyclic test. Characterizations by optical microscope and XPS were further performed to explain the mechanism. To sum up, it can be believed that the graphene protection barrier can dramatically enhance the reliability of the ECAs joints on Cu-Plated PCB substrate.
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| 3. |
- Li, Haohao, et al.
(författare)
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Atomic Layer Deposition of Buffer Layers for the Growth of Vertically Aligned Carbon Nanotube Arrays
- 2019
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Ingår i: Nanoscale Research Letters. - : Springer Science and Business Media LLC. - 1556-276X .- 1931-7573. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Vertically aligned carbon nanotube arrays (VACNTs) show a great potential for various applications, such as thermal interface materials (TIMs). Besides the thermally oxidized SiO 2 , atomic layer deposition (ALD) was also used to synthesize oxide buffer layers before the deposition of the catalyst, such as Al 2 O 3 , TiO 2 , and ZnO. The growth of VACNTs was found to be largely dependent on different oxide buffer layers, which generally prevented the diffusion of the catalyst into the substrate. Among them, the thickest and densest VACNTs could be achieved on Al 2 O 3 , and carbon nanotubes were mostly triple-walled. Besides, the deposition temperature was critical to the growth of VACNTs on Al 2 O 3 , and their growth rate obviously reduced above 650 °C, which might be related to the Ostwald ripening of the catalyst nanoparticles or subsurface diffusion of the catalyst. Furthermore, the VACNTs/graphene composite film was prepared as the thermal interface material. The VACNTs and graphene were proved to be the effective vertical and transverse heat transfer pathways in it, respectively.
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| 4. |
- Li, Haohao, et al.
(författare)
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Chemical Vapor Deposition of Vertically Aligned Carbon Nanotube Arrays: Critical Effects of Oxide Buffer Layers
- 2019
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Ingår i: Nanoscale Research Letters. - : Springer Science and Business Media LLC. - 1556-276X .- 1931-7573. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Vertically aligned carbon nanotubes (VACNTs) were synthesized on different oxide buffer layers using chemical vapor deposition (CVD). The growth of the VACNTs was mainly determined by three factors: the Ostwald ripening of catalyst nanoparticles, subsurface diffusion of Fe, and their activation energy for nucleation and initial growth. The surface roughness of buffer layers largely influenced the diameter and density of catalyst nanoparticles after annealing, which apparently affected the lifetime of the nanoparticles and the thickness of the prepared VACNTs. In addition, the growth of the VACNTs was also affected by the deposition temperature, and the lifetime of the catalyst nanoparticles apparently decreased when the deposition temperature was greater than 600 °C due to their serious Ostwald ripening. Furthermore, in addition to the number of catalyst nanoparticles, the density of the VACNTs was also largely dependent on their activation energy for nucleation and initial growth.
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| 5. |
- Yuan, G., et al.
(författare)
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Critical atomic-level processing technologies: Remote plasma-enhanced atomic layer deposition and atomic layer etching
- 2018
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Ingår i: Micro and Nanosystems. - : Bentham Science Publishers Ltd.. - 1876-4037 .- 1876-4029. ; 10:2, s. 76-83
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Forskningsöversikt (refereegranskat)abstract
- As feature sizes of devices shrink every year, deposition and etching processes change to be very challenge, especially for sub-7 nm technology node. The acceptable variability of feature size is expected to be several atoms of silicon/germanium in the future. Therefore, Remote Plasma-Enhanced Atomic Layer Deposition (RPE-ALD) and Atomic Layer Etching (ALE) change to be more and more important in the semiconductor fabrication. Due to their self-limiting behavior, the atomic-scale fidelity could be realized for both of them in the processes. Compared with traditional Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) methods, atomic-scale thickness controllability and good conformality can be achieved by RPE-ALD. Unlike conventional plasma etching, atomicscale precision and excellent depth uniformity can be achieved by ALE. The fundamentals and applications of RPE-ALD and ALE have been discussed in this paper. Using the combination of them, atomic-level deposition/etch-back method is also mentioned for achieving high quality ultra-thin films on three dimensional (3D) features.
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| 6. |
- Yuan, G., et al.
(författare)
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Graphene-based heat spreading materials for electronics packaging applications
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 172-174
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Konferensbidrag (refereegranskat)abstract
- Graphene-based heat spreading materials, including graphene-based film (GBF) and graphene-based electrically conductive adhesive (G-CA), were applied to electronics packaging. The thermal performances of GBF and G-CA were analyzed by resistance temperature detector (RTD) and thermal infrared imager. When the chip was covered by GBF and G-CA, the temperature of hotspot could be reduced by 3.1°C, at heat flux of 580 W/cm2. To analyze the thermal performances of G-CA and GBF in 3D electronics packaging, the distribution of temperature and temperature profiles on the top surface of chip were analyzed by COMSOL. Both of GBF and G-CA could obviously reduce the temperature of hotspot on the top surface of chip, compared with that on the bare chip. With G-CA and GBF, the temperature of hotspot could be reduced by 8°C. It suggests that both of G-CA and GBF are good heat spreading materials for electronics packaging application.
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| 7. |
- Yuan, G., et al.
(författare)
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Thermal interface materials based on vertically aligned carbon nanotube arrays: A review
- 2019
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Ingår i: Micro and Nanosystems. - : Bentham Science Publishers Ltd.. - 1876-4037 .- 1876-4029. ; 11:1, s. 3-10
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Forskningsöversikt (refereegranskat)abstract
- As the feature size of integrated circuit devices is shrinking to sub-7 nm node, the chip power dissipation significantly increases and mainly converted to the heat. Vertically Aligned Carbon Nanotube arrays (VACNTs) have a large number of outstanding properties, such as high axial thermal conductivity, low expansion coefficient, light-weight, anti-aging, and anti-oxidation. With a dramatic increment of chip temperature, VACNTs and their composites will be the promising materials as Thermal Interface Materials (TIMs), especially due to their high thermal conductivity. In this review, the synthesis, transfer and potential applications of VACNTs have been mentioned. Thermal Chemical Vapor Deposition (TCVD) has been selected for the synthesis of millimeter-scale VACNTs. After that, they are generally transferred to the target substrate for the application of TIMs in the electronics industry, using the solder transfer method. Besides, the preparation and potential applications of VACNTs-based composites are also summarized. The gaps of VACNTs are filled by the metals or polymers to replace the low thermal conductivity in the air and make them free-standing composites films. Compared with VACNTs- metal composites, VACNTs-polymer composites will be more suitable for the next generation TIMs, due to their lightweight, low density and good mechanical properties.
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| 8. |
- Yuan, G., et al.
(författare)
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Thermally reduced graphene oxide/carbon nanotube composite films for thermal packaging applications
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- Thermally reduced graphene oxide/carbon nanotube (rGO/CNT) composite films were successfully prepared by a high-temperature annealing process. Their microstructure, thermal conductivity and mechanical properties were systematically studied at different annealing temperatures. As the annealing temperature increased, more oxygen-containing functional groups were removed from the composite film, and the percentage of graphene continuously increased. When the annealing temperature increased from 1100 to 1400 °C, the thermal conductivity of the composite film also continuously increased from 673.9 to 1052.1 W m-1 K-1. Additionally, the Young's modulus was reduced by 63.6%, and the tensile strength was increased by 81.7%. In addition, the introduction of carbon nanotubes provided through-plane thermal conduction pathways for the composite films, which was beneficial for the improvement of their through-plane thermal conductivity. Furthermore, CNTs apparently improved the mechanical properties of rGO/CNT composite films. Compared with the rGO film, 1 wt% CNTs reduced the Young's modulus by 93.3% and increased the tensile strength of the rGO/CNT composite film by 60.3%, which could greatly improve its flexibility. Therefore, the rGO/CNT composite films show great potential for application as thermal interface materials (TIMs) due to their high in-plane thermal conductivity and good mechanical properties.
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