| 1. |
- Bao, Jie, 1982, et al.
(författare)
-
Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging
- 2016
-
Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:July 2016, s. 265501-
-
Tidskriftsartikel (refereegranskat)abstract
- The need for electrically insulating materials with a high in-plane thermal conductivity for lateral heat spreading applications in electronic devices has intensified studies of layered hexagonal boron nitride (h-BN) films. Due to its physicochemical properties, h-BN can be utilised in power dissipating devices such as an electrically insulating heat spreader material for laterally redistributing the heat from hotspots caused by locally excessive heat flux densities. In this study, two types of boron nitride based heat spreader test structures have been assembled and evaluated for heat dissipation. The test structures separately utilised a few-layer h-BN film with and without graphene enhancement drop coated onto the hotspot test structure. The influence of the h-BN heat spreader films on the temperature distribution across the surface of the hotspot test structure was studied at a range of heat flux densities through the hotspot. It was found that the graphene-enhanced h-BN film reduced the hotspot temperature by about 8–10°C at a 1000 W/cm2 heat flux density, a temperature decrease significantly larger than for h-BN film without graphene enhancement. Finite element simulations of the h-BN film predict that further improvements in heat spreading ability are possible if the thermal contact resistance between the film and test chip are minimised.
|
|
| 2. |
|
|
| 3. |
- Huang, Shirong, et al.
(författare)
-
Graphene Based Heat Spreader for High Power Chip Cooling Using Flip-chip Technology
- 2013
-
Ingår i: 2013 IEEE 15th Electronics Packaging Technology Conference (EPTC 2013). - 9781479928330 ; , s. 347-352
-
Konferensbidrag (refereegranskat)abstract
- Monolayer graphene was synthesized through thermal chemical vapor deposition (TCVD) as heat spreader for chip cooling. Platinum (Pt) serpentine functioned as hot spot on the thermal testing chip. The thermal testing chip with monolayer graphene film attached was bonded using flip-chip technology. The temperature at the hot spot with a monolayer graphene film as heat spreader was decreased by about 12°C and had a more uniform temperature compared to those without graphene heat spreader when driven by a heat flux of about 640W/cm 2 . Further improvements to the cooling performance of graphene heat spreader could be made by optimizing the synthesis parameters and transfer process of graphene films. © 2013 IEEE.
|
|
| 4. |
- Huang, Shirong, et al.
(författare)
-
Infrared Emissivity Measurement for Vertically Aligned Multiwall Carbon Nanotubes (CNTs) Based Heat Spreader Applied in High Power Electronics Packaging
- 2016
-
Ingår i: 6th Electronic System-integration Technology Conference (ESTC 2016). - 9781509014026 ; , s. Article no 7764696-
-
Konferensbidrag (refereegranskat)abstract
- Vertically-aligned multiwall carbon nanotubes were deposited on silicon substrate by low pressure chemical vapor deposition (LPCVD), which can be utilized as heat spreaders in high power electronic packaging due to their remarkable thermal conductivity. The infrared emissivity of the vertically aligned multiwall carbon nanotubes was then characterized based on the FLIR SC600 infrared imaging system. The average infrared emissivity of the multiwall carbon nanotubes sample was about 0.92, which agrees well with experimental results reported before. Scanning electron microscopy (SEM) images of the multiwall carbon nanotubes were further analyzed to explain its high emissivity, and the reason can be attributed to the homogeneous sparseness and aligned structure of the vertically aligned multiwall carbon nanotubes
|
|
| 5. |
- Huang, Shirong, et al.
(författare)
-
Reliability of Graphene-based Films Used for High Power Electronics Packaging
- 2015
-
Ingår i: 16th International Conference on Electronic Packaging Technology, ICEPT 2015, Changsha, China, 11-14 August 2015. - 9781467379991 ; , s. 852-855
-
Konferensbidrag (refereegranskat)abstract
- Graphene-base film was fabricated with chemical conversion process, including graphene oxide (GO) prepared by Hummer's method, graphene oxide reduced with L-ascorbic acid (LAA), graphene based film deposited by vacuum filtration process. Meanwhile, the functionalization of the graphene-based film was performed to decrease the thermal interface resistance between the graphene-based film and substrate. Characterization data showed that the graphene-based film possessed high reliability after 500 hours under 85°C aging test. In summary, the graphene-based film can be a promising solution in thermal management of high power electronics.
|
|
| 6. |
- Huang, Shirong, et al.
(författare)
-
The Effects of Graphene-Based Films as Heat Spreaders for Thermal Management in Electronic Packaging
- 2016
-
Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016. - 9781509013968 ; , s. Art no 7583272; Pages 889-892
-
Konferensbidrag (refereegranskat)abstract
- Graphene-based films (GBF) were fabricated using a chemical conversion process including graphene oxide (GO) preparation by use of Hummer’s method, graphene oxide reduction using L-ascorbic acid (LAA), and finally film formation by vacuum filtration. GBF is considered as a candidate material for thermal management, i.e. for removing heat from hotspots in power electronic packaging, due to its high thermal conductivity. In this work, the GBF heat spreading performance in 3D TSV packaging was analysed using finite element methods (FEM) implemented in the COMSOL software. Both size effects and the influence of the thermal conductivity of the GBF heat spreader on the thermal performance of the 3D TSV package were evaluated. Furthermore, the size effects of the thermal conductive adhesive (TCA) underfill between the chip and the printed circuit board (PCB) were analysed. The results obtained are critical for proper design of graphene-based lateral heat spreaders in high power electronic packaging.
|
|
| 7. |
- Lu, Xiuzhen, et al.
(författare)
-
The influence of sintering process on thermal properties of nano-silver paste
- 2018
-
Ingår i: 2018 19TH INTERNATIONAL CONFERENCE ON ELECTRONIC PACKAGING TECHNOLOGY (ICEPT). - 9781538663868 - 9781538663868 ; , s. 1157-1160
-
Konferensbidrag (refereegranskat)abstract
- Nano-silver paste with low sintering temperature and high operation temperature was introduced to the application of bonding materials for GaN and SiC devices. Thermal properties are critical issues for die attach materials due to the heat dissipation requirements of high power devices. The influence of sintering process parameters for nano-silver paste on the thermal properties was investigated. The thermal conductivity of sintered nano-silver paste increased with the increase of sintering temperature and sintering time because of the dense structure due to high temperature and long sintering time. To improve the thermal property, Ag coated micro-SiC particles were used as an alternative to partly replace pure nano-Ag particles. The results demonstrate that the SiC particles can reduce the voids and improve the density of the sintered silver structure. Moreover, the addition of SiC particles can also contribute to the increase of thermal diffusivity. As a result, the thermal conductivity of sintered silver paste with 1.5 wt.% Ag coated SiC particles was two times as compared to that without SiC particles with the same Ag concentration.
|
|
| 8. |
- Mu, Wei, 1985, et al.
(författare)
-
Enhanced Cold Wall CVD Reactor Growth of Horizontally Aligned Single-walled Carbon Nanotubes
- 2016
-
Ingår i: Electronic Materials Letters. - : Springer Science and Business Media LLC. - 1738-8090 .- 2093-6788. ; 12:3, s. 329-337
-
Tidskriftsartikel (refereegranskat)abstract
- Synthesis of horizontally-aligned single-walled carbon nanotubes (HA-SWCNTs) by chemical vapor deposition (CVD) directly on quartz seems very promising for the fabrication of future nanoelectronic devices. In comparison to hot-wall CVD, synthesis of HA-SWCNTs in a cold-wall CVD chamber not only means shorter heating, cooling and growth periods, but also prevents contamination of the chamber. However, since most synthesis of HA-SWCNTs is performed in hot-wall reactors, adapting this well-established process to a cold-wall chamber becomes extremely crucial. Here, in order to transfer the CVD growth technology from a hot-wall to a cold-wall chamber, a systematic investigation has been conducted to determine the influence of process parameters on the HA-SWCNT’s growth. For two reasons, the cold-wall CVD chamber was upgraded with a top heater to complement the bottom substrate heater; the first reason to maintain a more uniform temperature profile during HA-SWCNTs growth, and the second reason to preheat the precursor gas flow before projecting it onto the catalyst. Our results show that the addition of a top heater had a significant effect on the synthesis. Characterization of the CNTs shows that the average density of HA-SWCNTs is around 1-2 tubes/μm with high growth quality as shown by Raman analysis.
|
|
| 9. |
- Ye, Hui, et al.
(författare)
-
Preventing Aging of Electrically Conductive Adhesives on Metal Substrate Using Graphene-Based Barrier
- 2016
-
Ingår i: China Semiconductor Technology International Conference 2016, CSTIC 2016. - 9781467388047
-
Konferensbidrag (refereegranskat)abstract
- Electrically conductive adhesives (ECAs) seem to be a promising substitute to traditional metal-based solders, because of them being environmentally friendly materials requiring much lower processing temperatures, and offering a much finer pitch. However, a critical problem related to the use of ECAs is that the contact resistance to the metal pad tends to increase significantly during aging tests due to galvanic corrosion, particularly in 85oC/85% relative humidity (RH) atmospheres. In this respect the reported impermeability of graphene, a property prohibiting most molecules including water vapor from penetrating the film, has made graphene a major candidate as an anti-corrosion barrier material. The use of graphene as an anti-corrosion barrier material on steel and other metals has already been reported in literature. In this paper, the use of graphene-based barriers[12] between the ECA and the copper pads on a printed circuit board for alleviating the galvanic corrosion problem is reported. A PCB test board was designed for monitoring the effects of introducing the graphene-based barrier on the contact resistance between ECA and copper while exposing the board to a 500 hour aging test in 85℃/85% RH. For samples without graphene-based barriers it was found that the contact resistance increased rapidly during the first 200 hours of the aging test, while the contact resistance for samples with the graphene-based barriers remained stable. For these samples with graphene-based barriers, the contact resistance showed a much smaller decay during the aging test than for those samples without graphene-based barriers. These findings indicate that graphene-based barriers could be a solution for improving the reliability of electrically conductive adhesives, especially in harsh 85oC/85% RH environment conditions.
|
|
| 10. |
- Yuan, G., et al.
(författare)
-
A brief overview of atomic layer deposition and etching in the semiconductor processing
- 2016
-
Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016. - 9781509013968 ; , s. 1365-1368
-
Konferensbidrag (refereegranskat)abstract
- Atomic layer deposition (ALD) and atomic layer etching (ALE) are two important techniques in the semiconductor processing, which focus ultra-Thin film deposition and etching, respectively. Both of them have the self-limiting surface behavior, and could realize the atomic-scale fidelity in the deposition and etching processes. Unlike traditional chemical vapor deposition (CVD) and physical vapor deposition (PVD), ALD has good step coverage, atomic-scale thickness controllability, and composition uniformity at low growth temperature. Compared with traditional continuous-wave plasma etching, ALE has smooth surface, excellent depth uniformity and atomic-scale thickness controllability. In this review, their fundamental and applications have been discussed.
|
|
