| 1. |
- 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
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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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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Lai, H., et al.
(författare)
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A novel isotropic conductive adhesive with Ag flakes, BN and SiC nanoparticles
- 2010
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Ingår i: 2010 International Symposium on Advanced Packaging Materials: Microtech, APM '10. - 9781424467563 ; , s. 49-53
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Isotropic conductive adhesives (ICAs) with lower bonding temperature, higher resolution and environmental friendly have been used extensively in packaging process. In order to improve the electrical and thermal conductive properties of ICAs, two kinds of bimodal high temperature stable ICAs with matrix SHT6 and fillers with composition of macro silver flakes and boron nitride nanoparticles or macro silver flakes and silicon carbide nanoparticles were studied. In these two kinds of adhesives, the silver flakes were 75wt%, and the contents of nanoparticles were Owt%, 0.5wt%, 1.5wt%, 2.5wt%, 3wt%, 5wt% in weight. All the samples were cured at 150°C for 1 hour. SEM images and EDS results show the nanoparticles disperse randomly in the ICA. The electrical resistivity of these ICAs depends on the contents of silver flakes and is hardly affected by BN nanoparticles and SiC nanoparticles. The thermal conductivity of these ICAs increases firstly with the weight increase of the BN nanoparticles and SiC nanoparticles. And then it decreases when the content of the nanoparticles beyond a certain point. ©2010 IEEE.
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| 6. |
- Luo, Xin, 1983, et al.
(författare)
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Surface oxide analysis of lead-free solder particles
- 2013
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Ingår i: Soldering and Surface Mount Technology. - : Emerald. - 1758-6836 .- 0954-0911. ; 25:1, s. 39-44
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The composition and thickness of surface oxide of solder particles is extremely important to the quality of interconnect and reliability of packaged system. The purpose of this paper is to develop an observable measurement to research the issue. Design/methodology/approach - AES (Auger electron spectroscopy), XPS (X-ray photoelectron spectroscopy), TEM (transmission electron microscopy) and STEM (scanning transmission electron microscopy) were employed to examine the oxide layer on microscale solder powders. Conventional techniques and FIB (Focus Ion Beam) were employed for the TEM sample preparation. High angle annular dark field (HAADF) pattern was applied to distinguish the oxide layer and the solder matrix by the contrast of average atomic number. The results were confirmed by AES and XPS measurement. Findings - The solder powders were exposed to air (70% relative humidity) at 150 degrees C for 0, 120 and 240 h for the accelerated growth of oxide. The surface oxide thickness was 6 nm and 50 nm measured by TEM for Oh and 120 h samples, respectively. It was found that the increase in surface oxide thickness of solder particles is proportional to the rooting of time. The elemental distribution along the oxide was quantified by line scanning using STEM and the atomic ratio of Sn to O in the oxide layer nearer to the outer, the middle, and the inner (adjacent to the solder matrix) was found to be 1:2, 2:3 and 1:1, respectively. The result was validated using XPS which gave Sn to O ratio of 1:2 at 5 nm depth of surface oxide. Originality/value - This is the first time FIB technology has been used to prepare TEM specimens for solder particles and TEM pictures shown of their surface oxide layer. Though requiring more care in sample preparation, the measurements by TEM and STEM are believed to be more direct and precise.
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| 7. |
- Yang, Y., et al.
(författare)
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Heat dissipation performance of graphene enhanced electrically conductive adhesive for electronic 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. 125-128
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Konferensbidrag (refereegranskat)abstract
- Electrically conductive adhesive is a new type of environmentally interconnect material which can be used in electronic packaging to replace the traditional solders due to its advantages of simple applying process and low curing temperature. Silver coated graphene is employed in this work to enhance the thermal conductivity of the current commercial electrically conductive adhesive with very low thermal conductivity. Thermal conductivity of the electrically conductive adhesive was measured by laser flash thermal analyzer. The infrared thermal imager was utilized to obtain the temperature distribution of chip surface. The results indicated that the developed graphene enhanced electrically conductive adhesive has perfect heat performances. It can be believed that this new kind of electrically conductive adhesive possesses promising application in electronic packaging in the future.
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| 8. |
- Zhang, L., et al.
(författare)
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Study on the adhesion strength of new nano-structured polymer-metal composite for thermal interface material (Nano-TIM) under different pressures
- 2011
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Ingår i: Proceedings - 12th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2011, Shanghai, 8-11 August 2011. - 9781457717680 ; , s. 426-429
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Konferensbidrag (refereegranskat)abstract
- With the continual increase in cooling demand for microprocessors, the microelectronics industry has been increasingly focused on the development of thermal solutions. Thermal Interface Material (TIM) plays a key role in reducing the thermal resistance of packaging and the thermal resistance between the electronic device and the external cooling components. Nano-TIM, a new type of thermal interface material, was developed to improve the heat dissipation of electronic devices. This paper describes work undertaken to research the reliability of Nano-TIM. Pull tests were used to investigate the shear strength of samples with Nano-TIM of different thicknesses coalesced between two PCBs with Sn coating made under different pressure. Scanning Electron Microscopy (SEM) analysis techniques were used to determine the morphology of the shear fracture section after pull tests and observe the structure of the cross section of Nano-TIM coalesced between two PCBs with Sn coating.
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| 9. |
- Zhao, C. H., et al.
(författare)
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The promising application of graphene oxide as coating materials in orthopedic implants: preparation, characterization and cell behavior
- 2015
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Ingår i: Biomedical Materials (Bristol). - : IOP Publishing. - 1748-605X .- 1748-6041. ; 10:1, s. Art.no. 015019-
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the potential application of graphene oxide (GO) in bone repair, this study is focused on the preparation, characterization and cell behavior of graphene oxide coatings on quartz substrata. GO coatings were prepared on the substrata using a modified dip-coating procedure. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman spectroscopy results demonstrated that the as-prepared coatings in this study were homogeneous and had an average thickness of similar to 67 nm. The rapid formation of a hydroxyapatite (HA) layer in the simulated body fluid (SBF) on GO coated substrata at day 14, as proved by SEM and x-ray diffraction (XRD), strongly indicated the bioactivity of coated substrata. In addition, MC3T3-E1 cells were cultured on the coated substrata to evaluate cellular activities. Compared with the non-coated substrata and tissue culture plates, no significant difference was observed on the coated substrata in terms of cytotoxicity, viability, proliferation and apoptosis. However, interestingly, higher levels of alkaline phosphatase (ALP) activity and osteocalcin (OC) secretion were observed on the coated substrata, indicating that GO coatings enhanced cell differentiation compared with non-coated substrata and tissue culture plates. This study suggests that GO coatings had excellent biocompatibility and more importantly promoted MC3T3-E1 cell differentiation and might be a good candidate as a coating material for orthopedic implants.
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