| 1. |
- Du, Wenhui, et al.
(författare)
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New fast curing isotropic conductive adhesive for electronic packaging application
- 2010
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Ingår i: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010; Xi'an; 16 August 2010 through 19 August 2010. - 9781424481422 ; :Article number 5582446, s. 199-201
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Konferensbidrag (refereegranskat)abstract
- With the rapid development of technologies on high density assembly and packaging in electronic industry, isotropic conductive adhesive (ICA) has been paid more and more attention as a potential substitute of solder, due to its advantages of low processing temperature, simple processing conditions and good manufacturability. However, the curing time of most traditional ICA is more than half an hour. The process duration of ICA is 2 or 3 times longer than that of solder. Thus, low efficiencies of energy using and product manufacturing has been one of factors which limits widely application of ICA. Generally, the curing speed of ICA depends on types and amount of curing agent as well as curing temperature. In our previous experiments, the effects of curing temperature and amount of curing agent have been investigated. So, the present work attempts to choose a new kind of curing agent to shorten process duration of ICA. By using new curing agent, the curing duration of ICA could be shortened in 5 minutes with a high curing rate compared with the previous version. In addition, the basic performance including bulk resistivity and viscosity are also investigated in this work. Finally, we present some discussions about the further optimization of performance, for example regarding the ways of achieving better electrical conductivity with lower filler content and improvement of viscosity etc. © 2010 IEEE.
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| 2. |
- Fu, Yifeng, 1984, et al.
(författare)
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Selective growth of double-walled carbon nanotubes on gold films
- 2012
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Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 72, s. 78-80
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Tidskriftsartikel (refereegranskat)abstract
- Growth of high-quality vertical aligned carbon nanotube (CNT) structures on silicon supported gold (Au) films by thermal chemical vapor deposition (TCVD) is presented. Transmission electron microscopy (TEM) images show that the growth is highly selective. Statistical study reveals that 79.4% of the as-grown CNTs are double-walled. The CNTs synthesized on Au films are more porous than that synthesized on silicon substrates under the same conditions. Raman spectroscopy and electrical characterization performed on the as-grown double-walled CNTs (DWNTs) indicate that they are competitive with those CNTs grown on silicon substrates. Field emission tests show that closed-ended DWNTs have lower threshold field than those open-ended.
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| 3. |
- Lai, Huaxiang, et al.
(författare)
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Effects of BN and SiC nanoparticles on properties of conductive adhesive
- 2010
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Ingår i: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010; Xi'an; 16 August 2010 through 19 August 2010. - 9781424481422 ; :Article number 5582434, s. 235-239
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Konferensbidrag (refereegranskat)abstract
- Isotropic conductive adhesives (ICAs) are a type of interconnect material used more and more widely in computer, robot, mobile phone, LED and so on. Compared with traditional solders, isotropic conductive adhesives have better working plasticity, creep resistance and heat resistance. In particular, isotropic conductive adhesives are more responsive in high density packaging than solder, which determines the dominance of ICAs in high density packaging in the future. In order to improve the thermal conductivity of ICA with acceptable electrical conductivity, Ag flakers, BN and SiC nanoparticles were added into the matrix. The content of silver flakes was 75wt%, and the content of nanoparticles (BN or SiC) in the isotropic conductive adhesives were 0wt%, 0.5wt%, 1.5wt%, 2.5wt%, 3wt%, 5wt% in weight. The conductive adhesives were coated on the PCBs with stencil printing and fifty SR1206 chip components were mounted on a PCB using conductive adhesive. All samples were cured at 150°for 1h. Further research into the reliability of the above isotropic conductive adhesives after temperature & humidity and thermal-cycling was carried out to analyze the effects of BN and SiC nanoparticals on the properties of ICA. The condition of the temperature & humidity test was 85 ° /85%RH, 500h. The thermal-cycling test was -40 °∼125°, 500 cycles and the soaking time and ramping rate were 19min and ±15°/min. Changes to electrical resistance were used to estimate the reliability of the isotropic conductive adhesives in this study. The microstructure of the failure samples was observed using a Scanning Electron Microscope (SEM). The water absorption of all ICAs is the same after 94h temperature and humidity aging and the rate of water absorption is also the same during the aging. The ICA with 3% boron nitride nanoparticles and 75% micron silver flakes shows the best temperature and humidity reliability, with the fewest cracks on the interface between ICA and component. After 500h thermal cycling aging, the resistance reduces in the first 100h and maintains in a certain value after 332h cycled thermal. The samples have no wide cracks but a few small ones on the interface. © 2010 IEEE.
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| 4. |
- Chen, Si, 1981, et al.
(författare)
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A High Performance Ag Alloyed Nano-scale n-type Bi2Te3 Based Thermoelectric Material
- 2015
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Ingår i: Materials Today: Proceedings. - : Elsevier BV. - 2214-7853. ; 2:2, s. 610-619
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Konferensbidrag (refereegranskat)abstract
- A silver alloyed n-type bismuth telluride (Bi2Te3) thermoelectric (TE) bulk material with nano crystalline structure was studied and characterized in this paper. The Bi2Te3 nanopowders used in this study were first fabricated via a patented explosion based process. Then, the various concentrations of Ag nanoparticles (0-20 wt. %) were added into the Bi2Te3 nanopowders in order to increase the electrical conductivity. Combining the benefits of high electrical conductivity (1.51x10(5) S.m(-1)) and low thermal conductivity (0.441 W.m(-1).K-1), the dimensionless figure of merit (ZT value) of 1.48 for this n-type Bi2Te3 TE material is achieved at 300 K temperature.
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| 5. |
- Chen, Si, 1981, et al.
(författare)
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Sn-3.0Ag-0.5Cu Nanocomposite Solder Reinforced With Bi2Te3 Nanoparticles
- 2015
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Ingår i: IEEE Transactions on Components, Packaging and Manufacturing Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 2156-3985 .- 2156-3950. ; 5:8, s. 1186-1196
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Tidskriftsartikel (refereegranskat)abstract
- Nanocomposite solders are regarded as one of the most promising interconnect materials for the high-density electronic packaging due to their high mechanical strength and fine microstructure. However, the developments of nanocomposite solders have been limited by the inadequate compatibility between nanoparticles and solder matrix with respect to density, hardness, coefficient of thermal expansion, and surface activity. The compatibility issue will lead to a huge loss of nanoparticles from the solder matrix after the reflow soldering process. The thermal fatigue resistance of solder joint will also become degraded. Therefore, aiming to solve this problem, a novel nanocomposite solder consisting of Bi2Te3 semiconductor nanoparticles and Sn-3.0Ag-0.5Cu (SAC305) solder is presented. The effect of nanoparticles on the viscosity of solder paste and the void content of solder bump was first studied. Then, a series of analysis on the composition and microstructure of the solder bump were completed using transmission electron microscopy, X-ray diffraction, inductively coupled plasma-mass spectrometry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The survival rate of nanoparticles in the solder bump after reflow soldering process reaches as high as 80%. The refined microstructure was observed from the cross section of the nanocomposite solders. The shear test showed that the average mechanical strength of SAC305 solder after the addition of Bi2Te3 nanoparticles was higher. Meanwhile, no thermal fatigue resistance degradation was detected in the nanocomposite solder after 1000 thermal cycles in the range of -40 degrees C to 115 degrees C.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Fu, C., et al.
(författare)
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Optimization of stiffness for isotropic conductive adhesives
- 2010
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Ingår i: 2010 International Symposium on Advanced Packaging Materials: Microtech, APM '10. - 9781424467563 ; , s. 29-33
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With the rapid developments of electronic packaging, there is an increasing demand on high performance isotropic conductive adhesives (ICAs). However, the traditional ICAs are brittle, sensitive for crack formation and delamination, which is one of the major drawbacks that limits their use in a wide range of applications. Therefore great efforts have been made to make conductive adhesives more flexible. The present work aims at studying of several chemicals in terms of flexibilizing materials to modify the stiffuess modulus of the conductive adhesives. The effect of the flexibilizers has been characterized by different methods, such as Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), Thermogravimetric Analysis (TGA), etc. Moreover, the electrical resistance, thermal conductivity and viscosity are also measured in various conditions. Experimental results indicate that one of the flexibilizing materials using flexible ester-linkage is particular of interest as it offers low electrical resistance, high thermal performance and low modulus without decreasing glass transition temperature (Tg) and influencing curing and decomposition conditions. ©2010 IEEE.
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| 10. |
- Fu, Yifeng, 1984, et al.
(författare)
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Ultrafast Transfer of Metal Enhanced Carbon Nanotubes at Low Temperature for Large Scale Electronics Assembly
- 2010
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 22:44, s. 5039-5042
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Tidskriftsartikel (refereegranskat)abstract
- An indium-assisted ultrafast carbon nanotube (CNT) transfer method with a yield rate over 90% is described. Metal-coated as-transferred CNT structures exhibit excellent electrical performance that is at least one order of magnitude better than the previously published results. Shear test results show that the adhesion between CNTs and the substrate is greatly improved and excellent flexibility is obtained after the transfer process.
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