| 11. |
- Wang, Teng, 1983, et al.
(författare)
-
Development of Carbon Nanotube Bumps for Ultra Fine Pitch Flip Chip Interconnection
- 2006
-
Ingår i: 1st Electronics Systemintegration Technology Conference; Dresden, Saxony; Germany; 5 September 2006 through 7 September 2006. - 9781424405527 ; 2, s. 892-895
-
Konferensbidrag (refereegranskat)abstract
- Since 1991, carbon nanotubes have been considered for successful applications in various fields due to their unique properties. In the present work, carbon nanotubes are applied in integrated circuit packaging, as the bump interconnection for flip chip. The reason for choosing carbon nanotubes as the bump material is their special electrical, mechanical and thermal properties, which may promote both the performance and reliability of the flip chip packaging. Moreover, carbon nanotubes can be formed according to a precisely predefined small-scale pattern, which makes extremely high density interconnection possible. Vertically aligned carbon nanotubes are grown on silicon in the form of square arrays of different sizes, heights and pitches. Attempts to use thermal compression and anisotropic conductive adhesive to bond chips carrying carbon nanotube bumps with ceramic substrates are also executed. Mechanical testing is performed afterward to determine the strength of the bonding interfaces. The strength of the bonding by thermal compression is very weak, in the range from 1.9 to 7.0 g/mm2. The bonding by anisotropic conductive adhesive is much stronger, indicating a possible approach to bond chips carrying carbon nanotube bumps.
|
|
| 12. |
- Wang, Teng, 1983, et al.
(författare)
-
Low temperature transfer and formation of carbon nanotube arrays by imprinted conductive adhesive
- 2007
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:9
-
Tidskriftsartikel (refereegranskat)abstract
- This letter demonstrates the transfer and formation of aligned carbon nanotube (CNT) arrays at low temperature by imprinted conductive adhesive. A thermoplastic isotropic conductive adhesive is patterned by an imprint and heat transfer process. The CNTs grown by thermal chemical vapor deposition are then transferred to another substrate by the conductive adhesive, forming predefined patterns. The current-voltage response of the transferred CNT bundles verifies that good electrical connection has been established. This process can enable the integration of CNTs into various temperature-sensitive processeses and materials.
|
|
| 13. |
- Wang, Teng, 1983, et al.
(författare)
-
Through silicon vias filled with planarized carbon nanotube bundles
- 2009
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:48
-
Tidskriftsartikel (refereegranskat)abstract
- The feasibility of using carbon nanotube (CNT) bundles as the fillers of through silicon vias (TSVs) has been demonstrated. CNT bundles are synthesized directly inside TSVs by thermal chemical vapor deposition (TCVD). The growth of CNTs in vias is found to be highly dependent on the geometric dimensions and arrangement patterns of the vias at atmospheric pressure. The CNT-Si structure is planarized by a combined lapping and polishing process to achieve both a high removal rate and a fine surface finish. Electrical tests of the CNT TSVs have been performed and their electrical resistance was found to be in the few hundred ohms range. The reasons for the high electrical resistance have been discussed and possible methods to decrease the electrical resistance have been proposed.
|
|
| 14. |
|
|
| 15. |
- Zhang, Yan, 1976, et al.
(författare)
-
Experimental and Modeling of the Stress-Strain Behavior of a BGA Interconnect Due to Thermal Load
- 2008
-
Ingår i: Journal of Electronic Packaging, Transactions of the ASME. - : ASME International. - 1528-9044 .- 1043-7398. ; 130:2, s. 0210101-0210107
-
Tidskriftsartikel (refereegranskat)abstract
- A plastic ball grid array component interconnect has been experimentally investigated and modeled on the basis of micropolar theory. The experimental results were analyzed, and the data also provided the verification for the micropolar interface model. Two different interconnect cross sections, namely, one near the component boundary and the other in the center region beneath the chip, have been measured. The effects of thermal cycling on the interconnect deformation have been considered. The deformation fields, due to the mismatch of the material properties of the constituents in the assembly system, have been observed by means of a multifunction macro-micro-moiré interferometer, whereby the displacement distributions have been obtained and analyzed for the different specimens. The interconnect layer is usually of smaller size as compared to the neighboring component, and there are even finer internal structures included in the interconnect. The scale difference makes conventional methods time consuming and of low efficiency. An interface model based on the micropolar theory has been developed, cf. Zhang, Y., and Larsson, R., 2007, "Interface Modelling of ACA Flip-Chip Interconnects Using Micropolar Theory and Discontinuous Approximation," Comput. Struct., 85, pp. 1500-1513, Larsson, R., and Zhang, Y., 2007, "Homogenization of Microsystem Interconnects Based on Micropolar Theory and Discontinuous Kinematics, " J. Mech. Phys. Solids, 55, pp. 819-841, aiming at predicting the interconnect behavior under thermal load, especially when there exist internal structures in the interface and the component/ structure sizes vary in a wide range. Numerical simulations, using the micropolar interface model, show a fairly good agreement between the experimental data and the numerical simulations.
|
|
| 16. |
- Zhang, Yan, 1976, et al.
(författare)
-
Experimental investigation and micropolar modelling of the anisotropic conductive adhesive flip-chip interconnection
- 2008
-
Ingår i: Electrically Conductive Adhesives. - 9789004187825 ; 22:14, s. 1717-1731
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- A conductive adhesive is a promising interconnection material for microsystem packaging. The interconnect features are of great importance to system responses under various loading conditions. The flip-chip packaging system with anisotropic conductive film (ACF) joint under thermal loadings has been investigated both experimentally and theoretically. The displacement distributions have been measured by an interferometer, which could provide the in-plane whole-field deformation observation. The interconnection is of much smaller scales compared with the neighbouring components such as the chip and substrate, and there are even finer internal structures involved in the joint. The wide scale range makes both experimental observation and conventional simulation difficult. A micropolar model is thus developed. Utilizing the homogenization, this model requires low computation resource. Combination of this model with a secondorder model was able to produce a highly efficient and valid prediction of the packaging system response under thermal and mechanical loadings. Comparison of the micropolar model simulation and experimental data shows good agreement.
|
|
| 17. |
- Zhang, Yan, 1976, et al.
(författare)
-
Homogenization Model Based on Micropolar Theory for the Interconnection Layer in Microsystem Packaging
- 2006
-
Ingår i: Proceedings of the eight IEEE CPMT International Symposium on High Density Packaging and Component Failure Anlaysis (HDP´06). - 1424404886 ; , s. 166-170
-
Konferensbidrag (refereegranskat)abstract
- The increase in microsystem packaging density sets the requiement for component sizes in the system to become smaller and smaller. The scale decrease makes the analysis more complicated as the corresponding resolution should be improved to a great extent. Interconnection in the system is a typical interface structure that widely appear in the packaing system, in which periodic microstructures may be included inside. A homogenization model is developed in this paper, which focuses on the interface behavior. The interface model based on micropolar theory provides a natural way to include the characteristic scale that can reflect the size effect of the considered structure. Computations are carried out as the numerical example of the model, and comparisons of this model with those of the convertional method show its validity and efficiency.
|
|
| 18. |
|
|
| 19. |
- Zhang, Yan, 1976, et al.
(författare)
-
Interface Modelling of ACA Interconnects Using Micropolar Theory
- 2006
-
Ingår i: 2005 Conference on High Density Microsystem Design and Packaging and Component Failure Analysis, HDP'05; Shanghai; China; 27 June 2005 through 29 June 2005. - 9780780392939 ; , s. Art. no. 4017426-
-
Konferensbidrag (refereegranskat)abstract
- The contribution focuses on applying micro-polar theory which, as compared to the classical continuum theory, can offer the possiblity to include e.g. a micro-structural size-effect for the simulation and prediction of the interfacial stresses of microsystem interconnections, such as anisotropically conductive adhesives. As the dimension of the adhesive is much smaller than the chip or the substrate, it is treated as an interface zone with a finite thickness. The micro-polar theory is used in the vicinity of the interface to model the transfer of the couple stress across the interface, and a degenerated micro-polar continuum to model the interface, across which a displacement and a rotational jump is regularized. The paper is concluded by a numerical example involving the FE-representation of the interface formulation.
|
|
| 20. |
|
|
