| 21. |
- Daon, J., et al.
(författare)
-
Electrically conductive thermal interface materials based on vertically aligned carbon nanotubes mats
- 2014
-
Ingår i: IEEE 20th International Workshop on Thermal Investigation of ICs and Systems (Therminic). Greenwich, London, United Kingdom, 24-26 September 2014. - 9781479954155
-
Konferensbidrag (refereegranskat)abstract
- In power microelectronics, the trends towards miniaturization and higher performances result in higher power densities and more heat to be dissipated. In most electronic assembly, thermal interface materials (TIM) help provide a path for heat dissipation but still represent a bottleneck in the total thermal resistance of the system. VA-CNTs mats are typically grown on HR silicon substrate with Al2O3 diffusion barrier layer using Thermal CVD process. In many cases, 'die attach' thermal interface materials need to be electrically conductive and the growth of dense VA-CNT mats on an electrically conductive substrate remains a challenge. This paper presents the growth of dense VA-CNT mats on doped silicon with Al2O3 and TiN diffusion barrier layer. Processes, thermal and electrical characterization of VA-CNTs based thermal interface materials are studied and reported.
|
|
| 22. |
- Du, W., et al.
(författare)
-
Study into high temperature reliability of isotropic conductive adhesive
- 2011
-
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
-
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.
|
|
| 23. |
|
|
| 24. |
- Duan, Y., et al.
(författare)
-
A New Thermally Conductive Thermoplastic Die Attach Film
- 2012
-
Ingår i: Proceedings of IEEE CPMT 2012 International Conference on Electronic Packaging Technology & High Density Packaging. - 9781467316804 ; , s. 212-215
-
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.
|
|
| 25. |
- Fałat, T., et al.
(författare)
-
Experimental results versus numerical simulations of In/Cu intermetallic compounds growth
- 2014
-
Ingår i: Proceedings of the 16th Electronics Packaging Technology Conference, EPTC 2014, Marina Bay Sands, Singapore, 3-5 December 2014. - 9781479969944 ; , s. 797-800
-
Konferensbidrag (refereegranskat)abstract
- Indium is often used as a solder material which also plays a role of thermal interface e.g. in power LED systems. Indium and copper forms the intermetallic compounds. The growth rate constant at 400 K between copper and indium by the molecular dynamics simulations, as well as, experimentally was investigated. The results shown that the growth of the intermetallic compound in both cases follows the parabolic low, which indicates that the growth was mainly controlled by volume diffusion.
|
|
| 26. |
- Fan, Q., et al.
(författare)
-
The effect of functionalized silver on properties of conductive adhesives
- 2011
-
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
-
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.
|
|
| 27. |
- Fan, Q., et al.
(författare)
-
The effect of functionalized silver on rheological and electrical properties of conductive adhesives
- 2011
-
Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781607682356 ; 34:1, s. 811-816
-
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.
|
|
| 28. |
- Fan, X., et al.
(författare)
-
Reliability of carbon nanotube bumps for chip on glass application
- 2014
-
Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962753-
-
Konferensbidrag (refereegranskat)abstract
- Carbon nanotubes (CNTs) are an ideal candidate material for electronic interconnects due to their extraordinary thermal, electrical and mechanical properties. In this study, densified CNT bumps utilizing the paper-mediated controlled method were applied as the interconnection for chip on glass (COG) applications, and the silicon chip with patterned CNT bumps was then flipped and bonded onto a glass substrate using anisotropic conductive adhesive (ACA) at a bonding pressure of 127.4 Mpa, 170°C for 8 seconds. The electrical properties of the COG were evaluated with the contact resistance of each bump measured using the four-point probe method. Three different structure traces, marked as Trace A, Trace B, and Trace C, were tested, respectively. Thermal cycling (-40 to 85°C, 800 cycles) and damp heat tests (85°C/85% RH, 1000 hours) were also conducted to evaluate the reliability of the CNT-COG structure. The average contact resistance of the samples was recorded during these tests, in which there was no obvious electrical failure observed after both the thermal cycling and damp heat tests. The results of these tests indicated that the COG has good reliability and the CNT bumps have promising potential applications in COG.
|
|
| 29. |
- Fu, C., et al.
(författare)
-
Optimization of stiffness for isotropic conductive adhesives
- 2010
-
Ingår i: 2010 International Symposium on Advanced Packaging Materials: Microtech, APM '10. - 9781424467563 ; , s. 29-33
-
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.
|
|
| 30. |
- Fu, Yifeng, 1984, et al.
(författare)
-
A complete carbon-nanotube-based on-chip cooling solution with very high heat dissipation capacity
- 2012
-
Ingår i: Nanotechnology. - : IOP Publishing. - 1361-6528 .- 0957-4484. ; 23:4
-
Tidskriftsartikel (refereegranskat)abstract
- Heat dissipation is one of the factors limiting the continuous miniaturization of electronics. In the study presented in this paper, we designed an ultra-thin heat sink using carbon nanotubes (CNTs) as micro cooling fins attached directly onto a chip. A metal-enhanced CNT transfer technique was utilized to improve the interface between the CNTs and the chip surface by minimizing the thermal contact resistance and promoting the mechanical strength of the microfins. In order to optimize the geometrical design of the CNT microfin structure, multi-scale modeling was performed. A molecular dynamics simulation (MDS) was carried out to investigate the interaction between water and CNTs at the nanoscale and a finite element method (FEM) modeling was executed to analyze the fluid field and temperature distribution at the macroscale. Experimental results show that water is much more efficient than air as a cooling medium due to its three orders-of-magnitude higher heat capacity. For a hotspot with a high power density of 5000 W cm(-2), the CNT microfins can cool down its temperature by more than 40 degrees C. The large heat dissipation capacity could make this cooling solution meet the thermal management requirement of the hottest electronic systems up to date.
|
|
