| 1. |
- Chen, S., et al.
(författare)
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A solder joint structure with vertically aligned carbon nanofibres as reinforcements
- 2014
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Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962851-
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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.
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| 2. |
- Fan, X., et al.
(författare)
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Reliability of carbon nanotube bumps for chip on glass application
- 2014
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Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962753-
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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.
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| 3. |
- Jiang, Di, 1983, et al.
(författare)
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Carbon nanotube/solder hybrid structure for interconnect applications
- 2014
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Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962751-
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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.
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| 4. |
- Zhang, Yong, 1982, et al.
(författare)
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Use of graphene-based films for hot spot cooling
- 2014
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Ingår i: Proceedings of the 5th Electronics System-Integration Technology Conference, ESTC 2014. - 9781479940264 ; , s. Art. no. 6962834-
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Konferensbidrag (refereegranskat)abstract
- Efficient heat dissipation is becoming an urgent demand in electronics and optoelectronics because of increasing power density, which is generating more heat than ever. Graphene, an atomic layer of carbon, has been shown to have high thermal conductivity, which makes this material a promising candidate for heat dissipation in electronics. Here, we demonstrate a new type of graphene-based film on a test platform to alleviate the thermal issues. Taking advantage of its high in-plane thermal conductivity, CVD-grown graphene has been observed to possess a strong heat-spreading ability. In this paper, a chemical conversion process, including chemical oxidation, exfoliation and reduction, is utilised to fabricate the graphene-based films. Additionally, functionalisation of the film was also performed to diminish the interface thermal resistance between the chip surface and the graphene-based films. Thermal characterisation showed a capacity for effective heat removal, which was indicated by the decrease in the hot spot temperature at the same power loading. In summary, this facile approach may technologically enable large-scale fabrication of graphene-based films for thermal management in high power density devices.
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