| 1. |
- Chen, Si, 1981, et al.
(författare)
-
Sn-3.0Ag-0.5Cu Nanocomposite Solder Reinforced With Bi2Te3 Nanoparticles
- 2015
-
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
-
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.
|
|
| 2. |
- Jeppson, Kjell, 1947, et al.
(författare)
-
Through-Silicon Vias Filled With Densified and Transferred Carbon Nanotube Forests
- 2012
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 33:3, s. 420-422
-
Tidskriftsartikel (refereegranskat)abstract
- Through-silicon vias (TSVs) filled with densified and transferred carbon nanotube (CNT) forests are experimentally demonstrated. The filling is achieved by a postgrowth low-temperature transfer process at 200oC instead of direct CNT growth in the vias normally requiring high temperature. A vapor densification method is also applied to densify the as-grown CNT forests, which allows for packing more CNTs in the vias to reduce their resistances. CNT-filled TSVs fabricated based on these two key steps show CMOS compatibility and roughly one order of magnitude reduction in resistivity compared to the TSVs filled with as-grown undensified CNT forests.
|
|
| 3. |
- Jiang, Di, 1983, et al.
(författare)
-
Carbon Nanotubes in Electronics Interconnect Applications with a Focus on 3D-TSV Technology
- 2012
-
Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781607683186 ; 44:1, s. 683-692
-
Konferensbidrag (refereegranskat)abstract
- High density electronics integration at the system level, supported by advanced packaging solutions, is expected to be the main driving force for the future shrinking of electronics. One recent focus in the field of electronics packaging is the use of through-silicon-via (TSV) to form three-dimensional (3D) integration. A central task in developing 3D-TSV integration is to build reliable and efficient electrical interconnects for signal transfer and power distribution among the stacked layers. Carbon nanotubes (CNTs) are supposed to be a promising material to build future interconnects due to their many attractive electrical and mechanical properties. This paper reviews the state-of-art in CNT integration technology, with a focus on the 3D-TSV interconnect. The simplicity and manufacturability of fabricating and stacking CNT TSVs presented in this paper indicate a great application potential of CNTs as an interconnection material in future 3D integrated electronics.
|
|
| 4. |
- Jiang, Di, 1983, et al.
(författare)
-
Paper-mediated controlled densification and low temperature transfer of carbon nanotube forests for electronic interconnect application
- 2013
-
Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317. ; 103, s. Pages 177-180
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the fabrication and characterization of densified and transferred carbon nanotube forests for electronic interconnect application. A simple, low cost and quality method is developed for densifying vertically-aligned carbon nanotube (VA-CNTs) forests at room temperature. Commercially available paper is utilized in this work to serve as a solvent carrier. Highly densified CNT bundles are formed by the sorption of evaporative liquid from the paper into carbon nanotube forests. An average Young’s modulus increase from approximately 15.8 to 111.9 MPa is extrapolated from the measured load–displacement curves in the compression tests of the as-densified VA-CNTs. Subsequent low temperature transfer method is used to transfer the VA-CNT bundles onto the target substrate. Four-probe measurement of the transferred VA-CNTs shows resistance of 3.70 ± 0.04 Ω of each CNT bundle.
|
|
| 5. |
- Liu, Johan, 1960, et al.
(författare)
-
Carbon Nanotubes for Electronics Manufacturing and Packaging: From Growth to Integration
- 2013
-
Ingår i: Advances in Manufacturing. - : Springer Science and Business Media LLC. - 2095-3127 .- 2195-3597. ; 1:1, s. 13-27
-
Forskningsöversikt (refereegranskat)abstract
- Carbon nanotubes (CNTs) possess excellent electrical, thermal and mechanical properties. They are light in weight yet stronger than most of the other materials. They can be made both highly conductive and semi-conductive. They can be made from nano-sized small catalyst particles and extend to tens of millimeters long. Since CNTs emerged as a hot topic in the early 1990s, numerous research efforts have been spent on the study of the various properties of this new material. CNTs have been proposed as alternative materials of potential excellence in a lot of applications such as electronics, chemical sensors, mechanical sensors/actuators and composite materials, etc. This paper reviews the use of CNTs particularly in electronics manufacturing and packaging field. The progresses of three most important applications, including CNT-based thermal interface materials, CNT-based interconnections and CNT-based cooling devices are reviewed. The growth and post-growth processing of CNTs for specific applications are introduced and the tailoring of CNTs properties, i.e., electrical resistivity, thermal conductivity and strength, etc., is discussed with regard to specific application requirement. As the semiconductor industry is still driven by the need of getting smaller and faster, CNTs and the related composite systems as emerging new materials are likely to provide the solution to the future challenges as we make more and more complex electronics devices and systems.
|
|
| 6. |
- Wang, Teng, 1983, et al.
(författare)
-
Formation of three-dimensional carbon nanotube structures by controllable vapor densification
- 2012
-
Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 78, s. 184-187
-
Tidskriftsartikel (refereegranskat)abstract
- A new and versatile vapor densification method is developed to fabricate various three-dimensional and dual-porosity carbon nanotube (CNT) structures. By introducing the exposure time of CNTs to the solvent vapor as a control parameter to vary the amount of collected solvent, this method is capable of producing different degrees of densification with high controllability and uniformity. It is also found that the densification effect is highly dependent on the original CNT volume fractions in their forest form, low volume fraction causing shape distortion in densification. An O-2 plasma etching of the entangled nanotubes can help maintain the shapes of CNT forests, but only for those in a limited range of CNT volume fraction.
|
|
| 7. |
- Chen, S., et al.
(författare)
-
A solder joint structure with vertically aligned carbon nanofibres as reinforcements
- 2014
-
Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962851-
-
Konferensbidrag (refereegranskat)abstract
- In this paper, a solder joint structure was developed for the electronic packaging industry. Vertically aligned carbon nanofibres (VACNFs) were grown, transferred and used at the interface between Si/Au pads and Sn-3.0Ag-0.5Cu (SAC305) alloy as reinforcements in order to increase the solder joint thermal fatigue resistance. The transfer and assembly processes related to VACNFs were optimised and developed. The thermal cycling test results show that the thermal fatigue life of VACNF/SAC305 solder joints is 40% longer than that of pure SAC305. The dye and pry analysis and scanning electron microscopy observation prove that the VACNFs can effectively delay the crack propagation near the interface and consequently prolong the solder joint thermal fatigue life.
|
|
| 8. |
- Daon, J., et al.
(författare)
-
Chemically enhanced carbon nanotubes based Thermal Interface Materials
- 2015
-
Ingår i: THERMINIC 2015 - 21st International Workshop on Thermal Investigations of ICs and Systems 2015. - 9781467397056
-
Konferensbidrag (refereegranskat)abstract
- With progress in microelectronics the component density on a device increases drastically. As a consequence the power density reaches levels that challenge device reliability. New heat dissipation strategies are needed to efficiently drain heat. Thermal Interface Materials (TIMs) are usually used to transfer heat across interfaces, for example between a device and its packaging. Vertically Aligned Carbon Nanotubes (VACNTs) can be used to play this role. Indeed, carbon nanotubes are among the best thermal conductors (similar to 3.000 W/mK) and in the form of VACNT mats, show interesting mechanical properties. On one side, VACNTs are in contact with their growth substrate and there is a low thermal resistance. On the other side, good contact must be created between the opposite substrate and the VACNTs in order to decrease the contact thermal resistance. A thin-film deposition of an amorphous material can be used to play this role. This paper reports a chemically enhanced carbon nanotube based TIM with creation of chemical bonds between the polymer and VACNTs. We show that these covalent bonds enhance the thermal transfer from VACNTs to a copper substrate and can dramatically decrease local resistances. Implementation processes and thermal characterizations of TIMs are studied and reported.
|
|
| 9. |
- 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.
|
|
| 10. |
- 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.
|
|
| 11. |
- Jeppson, Kjell, 1947, et al.
(författare)
-
Test structures for studying flexible interconnect supported by carbon nanotube scaffolds
- 2017
-
Ingår i: IEEE International Conference on Microelectronic Test Structures. ; 2017
-
Konferensbidrag (refereegranskat)abstract
- Due to their flexibility and compatibility withsilicon devices, the use of carbon nanotubes as scaffolds for metal interconnect in flexible and wearable electronics has been proposed. This paper examines the performance of dual-height carbon nanotubes as flexible scaffolds for horizontal and vertical interconnects. For this purpose, a number of test structures have been designed and fabricated and their electrical and mechanical performance been investigated.
|
|
| 12. |
- Jiang, Di, 1983, et al.
(författare)
-
A flexible and stackable 3D interconnect system using growth-engineered carbon nanotube scaffolds
- 2017
-
Ingår i: Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 2:2
-
Tidskriftsartikel (refereegranskat)abstract
- One of the critical challenges for realizing flexible electronic systems for a wide range of applications is the development of materials for flexible and stackable interconnects. We propose and demonstrate a three-dimensional (3D)interconnect structure embedded in a polymeric substrate using metal-coated carbon nanotube (CNT)scaffolds. By using two different underlayer materials for the catalyst, onestep synthesis of a dual-height CNT interconnect scaffold was realized. The CNT scaffolds serve as flexible cores for both annular metal through-substrate-vias and for horizontal metal interconnect. The 3D-CNT network was fabricated on a silicon substrate, and once the scaffolds were covered by metal, they were embedded in a polymer serving as a flexible substrate after peel-off from the silicon substrate. The 3D-CNT interconnect network was exposed to mechanical bending and stretching tests while monitoring its electrical properties. Even after 300 cycles no significant increase of resistances was found. Electrically there is a trade-off between flexibility and conductivity due to the surface roughness of the scaffold. However, this is to some extent alleviated by the metalized sidewalls giving the horizontal wires a cross-sectional area larger than indicated by their footprint. For gold wires 200 nm thick, measurements indicated a resistivity of 18 μΩ.cm, a value less than one order of magnitude larger than that of bulk gold, and a value that is expected to improve as technology improves. The mechanical properties of the metalized scaffolds were simulated using a finite element model. The potential scale-up capability of the proposed 3D-CNT network was demonstrated by the stacking of two such polymer-embedded interconnect systems.
|
|
| 13. |
- Jiang, Di, 1983
(författare)
-
Carbon Nanotube Based Interconnect Material for Electronic Applications
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Carbon nanotubes (CNTs) are considered as a candidate material for future electronicinterconnect applications. This thesis summarizes the research work on thefabrication and characterization of CNT-based interconnect systems, and exploresthe possibilities of integrating CNTs into various electronic interconnect scenarios.CNT material properties and fabrication methods are introduced as well as its potentialfor solving the future interconnect challenges. The technology developmentworks are presented in detail in four categories: synthesis, densification, coatingand transfer.The principles of the chemical vapor deposition (CVD) method for producing theCNTs are described and discussed. Densification methods are developed in orderto increase the volume density of the pristine porous CVD-grown CNTs. Two techniques,vapor-based densification and paper-mediated wet densification, have beenproposed and characterized. CNT transfer techniques are developed in order todecouple the harsh CVD growth environment from the target application devices.Two kinds of transfer medium materials, indium and polymer, have been proposedand optimized. To improve the electrical performance of the pristine CNTs, metalliccoating techniques for both vertically aligned and randomly dispersed CNTsare developed and characterized.Finally, three different CNT-based interconnect scenarios: bumps, through siliconvias, and flexible conductors, are demonstrated and characterized, using theas-developed processes. The integration technologies developed in this thesis notonly improve the CNT process compatibility with the conventional electronicsmanufacture flows, but also offers state-of-the-art electrical and mechanical performancefor the non-conventional flexible and stretchable interconnect applications.
|
|
| 14. |
- Jiang, Di, 1983, et al.
(författare)
-
Carbon nanotube/solder hybrid structure for interconnect applications
- 2014
-
Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962751-
-
Konferensbidrag (refereegranskat)abstract
- A carbon nanotube (CNT)/Solder hybrid bump structure is proposed in this work in order to overcome the drawbacks of high CNT resistivity while retaining the advantages of CNTs in terms of interconnect reliability. Lithographically defined hollow CNT moulds are grown by thermal chemical vapor deposition (TCVD). The space inside the CNT moulds is filled up with Sn-Au-Cu (SAC) solder spheres of around 10 μm in diameter. This CNT/Solder hybrid material is then reflowed and transferred onto target indium coated substrate. The reflow melts the small solder spheres into large single solder balls thus forming a hybrid interconnect bump together with the surrounding densified CNT walls, which the CNT and the solder serve as resistors in parallel. The electrical resistance of such a CNT/Solder structure is measured to be around 6 folds lower than pure CNT bumps.
|
|
| 15. |
- Jiang, Di, 1983, et al.
(författare)
-
Electrical Interconnects Made of Carbon Nanotubes: Applications in 3D Chip Stacking
- 2012
-
Ingår i: IMAPS Nordic Annual Conference Proceedings 2012, Helsingor, 2 - 4 September 2012. - 9781622763160 ; , s. 150-159
-
Konferensbidrag (refereegranskat)abstract
- High density electronics integration at the system level, supported by advanced packaging solutions, is expected to be the driving force for the future down-scaling of semiconductor electronics. One recent focus in the field of electronic packaging is the use of through-silicon-vias (TSVs) to form three-dimensional (3D) integration. A central task in developing 3D chip integration is to build reliable and efficient 3D electrical interconnects for signal transfer and power distribution among the stacked layers. Carbon nanotubes (CNTs) are proposed to be a promising material to build future interconnects due to their many attractive electrical and mechanical properties. This paper reviews the state-of-art in CNT integration technology, with a focus on the application of 3D chip stacking TSV interconnects. The simplicity and manufacturability of fabricating CNT TSVs presented in this paper indicate a great application potential of CNTs as an interconnection material in future 3D integrated electronics.
|
|
| 16. |
- Jiang, Di, 1983, et al.
(författare)
-
Embedded Fin-Like Metal/CNT Hybrid Structures for Flexible and Transparent Conductors
- 2016
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 12:11, s. 1521-1526
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, an embedded fin-like metal-coated carbon nanotube (Fin-M/CNT) structure is demonstrated for flexible and transparent conductor wire applications. Embedded in a polydimethylsiloxane polymeric substrate, Fin-M/CNT wires with a minimum width of 5 μm and a minimum pitch of 10 μm have been achieved. Direct current resistances of single Fin-M/CNT wires, where the supporting CNT structures have been covered by Ti/Al/Au metal coatings of different thicknesses, have been measured. The high aspect ratio of the fin-like structures not only improves the adhesion between the wires and the polymeric substrate, but also yields a low resistance at a small surface footprint. In addition, transparent Fin-M/CNT grid lines with hexagonal patterns, with a sheet resistance of as low as 45 Ω sq−1, have been achieved at an optical transmittance of 88%. The robustness of the Fin-M/CNT structures has been demonstrated in bending tests up to 500 cycles and no significant changes in wire resistances are observed.
|
|
| 17. |
- Jiang, Di, 1983, et al.
(författare)
-
Room Temperature Transfer of Carbon Nanotubes on Flexible Substrate
- 2012
-
Ingår i: Proceedings of the 18th Therminic International Workshop on Thermal Investigations of ICs and Systems, Budapest, 25-27 September 2012. - 9782355000225 ; , s. 213-216
-
Konferensbidrag (refereegranskat)abstract
- In this paper we report a novel method of transferring thermally grown vertically aligned carbon nanotubes (VA-CNTs) onto flexible substrates at room temperature with a single-step process. The transfer process is carried out by placing the CNT forests upside down on a double sided thermal release adhesive tape and peeling off the silicon substrate. Scanning electron microscope (SEM) is used to observe the transfer results. Also a second transfer using the same method but a thermal tape with higher release temperature is repeated on the as-transferred CNTs forests. The results show that this method is able to provide a novel process for transferring CNT forests at room temperature. This process will help to bring close the low cost fabrication of vertically aligned CNT structures for electronics.
|
|
| 18. |
|
|
| 19. |
- Jiang, Di, 1983, et al.
(författare)
-
Vertically stacked carbon nanotube-based interconnects for through silicon via application
- 2015
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 36:5, s. 499-501
-
Tidskriftsartikel (refereegranskat)abstract
- Stacking of silicon chips with carbon nanotube (CNT)-based through-silicon vias (TSVs) is experimentally demonstrated. Polymer filling is used to improve the transfer quality of CNTs into pre-etched silicon holes. Special hexagonal CNTs are designed to achieve high aspect ratio (10:1) CNT vias. TSVs filled with closely packed CNTs show a highly linear dc I - V response. The proposed process works at room temperature, which makes it compatible with existing device fabrication flow.
|
|
| 20. |
- Li, X., et al.
(författare)
-
Reliability of Carbon Nanotube Bumps for Chip on Film Application
- 2013
-
Ingår i: Proceedings of the IEEE Conference on Nanotechnology. - 1944-9399 .- 1944-9380. - 9781479906758 ; , s. 845-848
-
Konferensbidrag (refereegranskat)abstract
- Carbon nanotubes (CNTs) are an ideal candidate for electrical interconnects due to their extraordinary thermal, electrical and mechanical properties. In this work, as-densified CNT bumps were applied as chip on film (COF) interconnection material. A silicon chip with patterned CNT bumps was bonded onto a flexible substrate using anisotropic conductive adhesive (ACA) with bonding pressure, at 127.4 MPa, 170 °C and for 8 seconds. The electrical properties of this structure were evaluated by measuring the contact resistance of each bump using the four-point probe method. Thermal cycling (-40∼85°C, 1000 cycles) and damp heat tests (85°C/85% RH, 1000 hours) were conducted to evaluate the reliabilities of the CNT-COF structure bonded with ACA. The average contact resistances of two samples used for the reliability tests were 226 mΩ and 260mΩ. No electrical failure was observed after the damp heat test and only two were observed after the thermal cycling test. The average contact resistance was increased only 15.7% and 13.8%, respectively, after the thermal cycling and the damp heat tests. © 2013 IEEE.
|
|
| 21. |
- Liu, Johan, 1960, et al.
(författare)
-
CHEMICALLY VAPOR DEPOSITED CARBON NANOTUBES FOR VERTICAL ELECTRONICS INTERCONNECT IN PACKAGING APPLICATIONS
- 2014
-
Ingår i: Proceedings of the 12th international conference on Solid States and Integrated Circuits, ICSICT2014. - 9781479932962 ; , s. 47-50
-
Konferensbidrag (refereegranskat)abstract
- Carbon Nanotubes (CNTs) have excellent electrical, thermal and mechanical properties. They are mechanically strong at nanoscale yet also flexible if made micro- or milli-meter long. They are synthesized from nano-sized catalyst particles and can be made up to millimeters. A lot of research studies have been spent on various properties of the CNTs. They are regarded as an alternative material in a lot of applications such as ICs, MEMS, sensors, biomedical and other composite materials, etc. Among them, the thermally grown CNTs using chemical vapor deposition method is of particular interested in electronics applications as an interconnect material. This paper reviews the use of CNTs as an interconnect material for packaging applications. The growth and post-growth processing of CNTs are covered and the tailoring of CNTs properties, i.e. electrical resistivity, thermal conductivity and strength, etc., is discussed. To make the electronics systems smaller, faster and more power efficient, CNTs as a potential new material are likely to provide the solution to the future challenges as the electronics systems are getting more and more functional and complex nowadays.
|
|
| 22. |
- Mu, Wei, 1985, et al.
(författare)
-
Tape-Assisted Transfer of Carbon Nanotube Bundles for Through-Silicon-Via Applications
- 2015
-
Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 1543-186X .- 0361-5235. ; 44:8, s. 2898-2907
-
Tidskriftsartikel (refereegranskat)abstract
- Robust methods for transferring vertically aligned carbon nanotube (CNT) bundles into through-silicon vias (TSVs) are needed since CNT growth is not compatible with complementary metal–oxide–semiconductor (CMOS) technology due to the temperature needed for growing high-quality CNTs (∼700°C). Previous methods are either too complicated or not robust enough, thereby offering too low yields. Here, a facile transfer method using tape at room temperature is proposed and experimentally demonstrated. Three different kinds of tape, viz. thermal release tape, Teflon tape, and Scotch tape, were applied as the medium for CNT transfer. The CNT bundle was adhered to the tape through a flip-chip bonder, and the influence of the bonding process on the transfer results was investigated. Two-inch wafer-scale transfer of CNT bundles was realized with yields up to 97% demonstrated. After transfer, the use of several different polymers was explored for filling the gap between the transferred CNT bundle and the sidewalls of the TSV openings to improve the filling performance. The current–voltage characteristic of the CNT TSVs indicated good electrical performance, and by measuring the via resistance as a function of via thickness, contact resistances could be eliminated and an intrinsic CNT resistivity of 1.80 mΩ cm found.
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
- Wang, Nan, 1988, et al.
(författare)
-
Flexible Multifunctionalized Carbon Nanotubes-Based Hybrid Nanowires
- 2015
-
Ingår i: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 25:26, s. 4135-4143
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, flexible multifunctionalized carbon nanotube (CNT)-based hybrid nanowires are synthesized through surface modification processes. The good dispersability of the hybrid nanowire in polar solvents facilitates directly making fine patterns with a minimum width of 40 μm for applications of flexible and stretchable circuits (FSCs). The hybrid nanowire possesses a flexible and highly conductive structure which demonstrates stable electro-mechanical properties on polydimethylsiloxane (PDMS) substrates under large structural deformation. FSCs fabricated from the hybrid nanowires show a constant resistance of 0.096 Ω □-1 (equivalent of a resistivity 0.96 Ω μm) under repeated bending cycles. The FSCs also have a low and stable sheet resistance of 0.4 Ω □-1 for strains up to 30%, which is almost four orders of magnitude lower than that of pure CNT samples (1316 Ω □-1). Further improved stretchability and electro-mechanical properties (0.1 Ω □-1, at the strain of 100%) are achieved with a prestrain PDMS substrate. Repeated deformation tests demonstrate the high reliability of FSCs. The observed stable and reliable electro-mechanical performance of FSCs suggests the potential use of the material in wearable and portable electronics. Multifunctionalized hybrid nanowires based on carbon nanotubes are prepared through different surface modification processes. These hybrid nanowires exhibit both the high electrical conductivity of metal and excellent mechanical properties of carbon nanotubes together with good dispersability. Flexible and stretchable electrodes based on the hybrid nanowires demonstrate stable electro-mechanical properties under large structural deformations.
|
|
