| 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. |
- 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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| 3. |
- Tao, W., et al.
(författare)
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Reliability characterisation of bi-modal high temperature stable Isotropic Conductive Adhesives
- 2010
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Ingår i: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010, Xian, 16-19 August 2010. - 9781424481422 ; :Article number 5582437, s. 225-228
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Konferensbidrag (refereegranskat)abstract
- Conductive adhesives are generally considered to be one of the strongest candidates for replacement of solder in electronics industry. However, some problems related to the performance have so far limited wider applications of conductive adhesives. One of the major problems is tendency to degrade during temperature and humidity aging. In this paper, two kinds of Isotropic Conductive Adhesives (ICA) with high temperature stable matrix and different fillers were fabricated. The first one was fabricated by simply adding silver flakes into matrix as filler using this high temperature stable matrix based on highly cross-linked aromatic functional groups. For the second one, in addition to silver flakes, nanosilver particles with different weight percentages were also added as filler into matrix to form a bi-modal ICA. The weight percentages of nano-silver particles in filler are 1wt%, 2wt% and 3wt% respectively. The filler content of these two ICAs are both 75wt% in total. All test samples were cured at 150°for 1 hour. The random distribution of the silver flakes in the adhesive was observed by SEM. The bulk resistivity of the ICAs with different fillers was investigated to characterize the electrical conductivity of the ICA. The results show that addition of small amount of nano-silver particles improve the electric conductivity of the ICA but the excessive amount of nano-silver particles led to the increase of the ICA's bulk resistivity. The humidity (85°/85RH) test was carried out and the resistances of the samples were measured. It was shown that some electrical resistance increase was observed during the humidity testing with time. The addition of the nano-particles has also some negative effect of the electrical resistance change. But the effect is limited in a few percentage range of the nano-particle addition.
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| 4. |
- Du, W., et al.
(författare)
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Study into high temperature reliability of isotropic conductive adhesive
- 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. 1053-1055
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Konferensbidrag (refereegranskat)abstract
- With the rapid development of technologies for high density assembly and packaging in electronic industry, isotropic conductive adhesive (ICA) has been paid more and more attention as a potential substitute for solder, due to its advantages of low processing temperature, simple processing conditions and good manufacturability. However, studies into the reliability of ICA are not as abundant as those of solder. As a composite material, the failure feasibility of ICA not only depends not only on the variation in performance of different constituent parts, such as high temperature aging of the polymer, aging due to moisture absorption and oxidization of filler particles, but also on interface changes. Thus, the failure mechanism of ICA seems to be complicated and studies into the reliability of ICA are also necessary. Reliability in humidity and heat has been investigated in previous works, and in this paper high temperature reliability will be studied as a comparison. Some reliability tests and results will be given and some failure mechanisms discussed. Finally, we present some discussion about the further optimization of reliability for follow-up studies.
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| 5. |
- Duan, Y., et al.
(författare)
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A New Thermally Conductive Thermoplastic Die Attach Film
- 2012
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Ingår i: Proceedings of IEEE CPMT 2012 International Conference on Electronic Packaging Technology & High Density Packaging. - 9781467316804 ; , s. 212-215
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Konferensbidrag (refereegranskat)abstract
- As devices with smaller footprint and, higher functionality become the norm, stacked die technology will be required to enable the advancement of modern integrated packaging. As wafers become ever thinner to meet stacking requirements, new materials technology must address the challenges of handling and processing wafer thicknesses of less than 100 microns. Die attach film (DAF) has being widely used as an alternative. With its good control of bleed, consistent bond line thickness and simplified operation. In this paper, a kind of thermoplastic film with good thermal conductivity was developed for die attachment application and some of its properties, such as shear strength and, thermal conductivity were investigated. In the present work, the formula of the DAF matrix has been determined and in order to improve thermal conductivity of DAF, silicon carbide (SiC) particles with high thermal conductivity were selected to add as filler and in the content of SiC particles on the property of the DAFs were also investigated. Shear tests were conducted to measure the bonding strength of the DAFs. The results show that the films reached a 6.5 MPa in terms of average shear strength and after plasticizing it could reach 3.5 MPa. The thermal conductivity of the DAFs was 0.37W/ m·K.
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| 6. |
- Fan, Q., et al.
(författare)
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The effect of functionalized silver on properties of conductive adhesives
- 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. 423-425
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Konferensbidrag (refereegranskat)abstract
- This research used low molecular surface modifiers and observed that chemisorptions took place through the formation of a bond between silver surface and an adsorbed molecule, which improved the dispersion of silver flakes in the organic resin. Results of shear viscosity, bulk resistivity etc. showed that by using these low molecular organic functionalizers, isotropic conductive adhesives (ICAs) with lower shear viscosity and better electrical conductivity at high silver fillers content were obtained. Different processing methods and different matrixes were compared.
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| 7. |
- Fan, Q., et al.
(författare)
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The effect of functionalized silver on rheological and electrical properties of conductive adhesives
- 2011
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Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781607682356 ; 34:1, s. 811-816
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Konferensbidrag (refereegranskat)abstract
- This research used low molecular surface modifiers, and observed that chemisorptions took place through the formation of a bond between silver surface and an adsorbed molecule, which improved the dispersion of silver flakes in the organic resin. Several different functionalizers, such as thioglycolic acid, silane and di-acid, were used to functionalize the silver surface. Results of shear viscosity, bulk resistivity etc. showed that by using these low molecular organic functionalizers, isotropic conductive adhesives (ICAs) with lower shear viscosity and better electrical conductivity at high silver fillers content were obtained. The adipic acid had the greatest effect on the rheological and electrical property of ICAs, so its weight percentage in silver flakes was also optimized; ICAs displayed the maximum electrical conductivity when there was 0.5 wt% of silver flakes.
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| 8. |
- Li, D., et al.
(författare)
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Study into the application of single-wall carbon nanotubes in isotropic conductive adhesives
- 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. 430-435
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Konferensbidrag (refereegranskat)abstract
- Isotropic conductive adhesives (ICAs) with stable contact resistance and high thermal conductivity are highly desirable. In this paper, a new ICA filled with silver fillers and single-wall carbon nanotubes (SCNTs) was developed. SCNTs were acidified in a mixture of 98% H2S04 and 68% HN03 with a volume rate of 3:1 at 50 °C for 3 h. Carboxyl and hydroxyl groups were produced on SCNTs, and the purity of SCNTs also greatly improved. To prepare the ICAs, acidified SCNTs were firstly ultrasonically dispersed in acetone, then added into the matrix resin, and finally mixed with silver fillers. The bulk resistivity of the fabricated ICAs filled with silver fillers and acidified SCNTs was larger, their lap shear strength lower, their contact resistance stability improved, and their moisture absorption remained almost unchanged. In the curing process, the released heat was greatly reduced and transferred to the surroundings for good thermal conductivity of SCNTs, but the curing temperature was not affected. Therefore, acidified SCNTs can be used in ICAs, and in general, will create a good effect on ICAs.
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| 9. |
- Tang, X., et al.
(författare)
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Development and characterisation of nanofiber films with high adhesion
- 2011
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Ingår i: Proceedings - Electronic Components and Technology Conference. - 0569-5503. ; , s. 673-677
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Konferensbidrag (refereegranskat)abstract
- With the development of thermal management, thermal interface material (TIM) plays a more and more important role in electronic packaging. This paper reports the study on fabrication of a nanofiber films used for nano-thermal interface material (nano-TIM) with the adhesive function. The nano-TIM with high thermal conductivity and low thermal resistivity has been fabricated by electrospinning process. In the present work, hotmelt was added into the electrospinning solution to improve the adhesion properties of the film. The morphology of the film was observed by Scanning Electrical Microscope (SEM). The nanofiber films have a nano-scale structure with hotmelt randomly attached into the fiber matrix. Shear tests were conducted to measure the bonding strength of nanofiber films. The results show that the nanofiber films reached a 6.52 MPa in terms of average shear strength, more than 2 times better than the case without the hotmelt addition. © 2011 IEEE.
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