Advanced Thermal Interface Materials Using Natural Graphite

2003 ◽  
Author(s):  
Martin Smalc ◽  
Julian Norley ◽  
R. Andy Reynolds ◽  
Richard Pachuta ◽  
Dan W. Krassowski
Keyword(s):  
Polymeric Materials ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Graphite Sheet ◽  
Mineral Oils ◽  
Sheet Materials ◽  
Flexible Graphite ◽  
Graphite Sheets ◽  
Interface Materials

Expanded flexible graphite sheet materials have become attractive as Thermal Interface Materials (TIM’s). Flexible graphite sheet materials were originally developed as gaskets for fluid sealing applications. Properties that make flexible graphite sheets of interest as TIM’s include their relatively high thermal conductivities and their ability to conform well to surfaces. Specific grades of flexible graphite have been developed for TIM applications. Because flexible graphite sheets are porous, with open interconnected pores, it is possible to impregnate these sheets with various materials to improve properties. In particular, various polymers, such as mineral oils, synthetic oils, etc can be added to flexible graphite to improve its performance in thermal interface applications. This paper will review the thermal properties of TIM’s made by adding two different polymeric materials to a grade of flexible graphite specifically developed as a thermal interface material.

scholarly journals Noncured Graphene Thermal Interface Materials for High-Power Electronics: Minimizing the Thermal Contact Resistance

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1699
Author(s):  
Sriharsha Sudhindra ◽  
Fariborz Kargar ◽  
Alexander A. Balandin
Keyword(s):  
Contact Resistance ◽  
High Power ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Wide Band ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Total Thermal Resistance ◽  
Thermal Interface ◽  
Interface Materials

We report on experimental investigation of thermal contact resistance, RC, of the noncuring graphene thermal interface materials with the surfaces characterized by different degree of roughness, Sq. It is found that the thermal contact resistance depends on the graphene loading, ξ, non-monotonically, achieving its minimum at the loading fraction of ξ ~15 wt %. Decreasing the surface roughness by Sq~1 μm results in approximately the factor of ×2 decrease in the thermal contact resistance for this graphene loading. The obtained dependences of the thermal conductivity, KTIM, thermal contact resistance, RC, and the total thermal resistance of the thermal interface material layer on ξ and Sq can be utilized for optimization of the loading fraction of graphene for specific materials and roughness of the connecting surfaces. Our results are important for the thermal management of high-power-density electronics implemented with diamond and other wide-band-gap semiconductors.

scholarly journals Thermal Properties of the Graphene Composites: Application of Thermal Interface Materials

2018 ◽  
Vol 7 (4.33) ◽  
pp. 530
Author(s):  
Mazlan Mohamed ◽  
Mohd Nazri Omar ◽  
Mohamad Shaiful Ashrul Ishak ◽  
Rozyanty Rahman ◽  
Zaiazmin Y.N ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Matrix Material ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Uniform Thickness ◽  
Thermal Interface ◽  
Interface Materials ◽  
Main Material

Epoxy mixed with others filler for thermal interface material (TIM) had been well conducted and developed. There are problem occurs when previous material were used as matrix material likes epoxy that has non-uniform thickness of thermal interface material produce, time taken for solidification and others. Thermal pad or thermal interface material using graphene as main material to overcome the existing problem and at the same time to increase thermal conductivity and thermal contact resistance. Three types of composite graphene were used for thermal interface material in this research. The sample that contain 10 wt. %, 20 wt. % and 30 wt. % of graphene was used with different contain of graphene oxide (GO).  The thermal conductivity of thermal interface material is both measured and it was found that the increase of amount of graphene used will increase the thermal conductivity of thermal interface material. The highest thermal conductivity is 12.8 W/ (mK) with 30 w. % graphene. The comparison between the present thermal interface material and other thermal interface material show that this present graphene-epoxy is an excellent thermal interface material in increasing thermal conductivity.  

Development of a Compliant Nanothermal Interface Material

2011 ◽  
Author(s):  
David Shaddock ◽  
Stanton Weaver ◽  
Ioannis Chasiotis ◽  
Binoy Shah ◽  
Dalong Zhong
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Thermal Stresses ◽  
Performance Testing ◽  
High Thermal Conductivity ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Bondline Thickness ◽  
Interface Materials

The power density requirements continue to increase and the ability of thermal interface materials has not kept pace. Increasing effective thermal conductivity and reducing bondline thickness reduce thermal resistance. High thermal conductivity materials, such as solders, have been used as thermal interface materials. However, there is a limit to minimum bondline thickness in reducing resistance due to increased fatigue stress. A compliant thermal interface material is proposed that allows for thin solder bondlines using a compliant structure within the bondline to achieve thermal resistance <0.01 cm2C/W. The structure uses an array of nanosprings sandwiched between two plates of materials to match thermal expansion of their respective interface materials (ex. silicon and copper). Thin solder bondlines between these mating surfaces and high thermal conductivity of the nanospring layer results in thermal resistance of 0.01 cm2C/W. The compliance of the nanospring layer is two orders of magnitude more compliant than the solder layers so thermal stresses are carried by the nanosprings rather than the solder layers. The fabrication process and performance testing performed on the material is presented.

Mechanical Modeling of a Solder Thermal Interface Material: Implications for Thermo-Mechanical Reliability

2005 ◽  
Author(s):  
Sankara J. Subramanian
Keyword(s):  
Failure Modes ◽  
Accelerated Testing ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Finite Element Models ◽  
Electronic Packages ◽  
Thermal Impedance ◽  
Thermal Interface ◽  
Service Conditions ◽  
Interface Materials

This paper addresses cracking in solder thermal interface materials (STIMs) used in electronic packages under accelerated testing or service conditions. Finite-element models of various packages have been built to study the deformation in the STIM through a few cycles of accelerated testing. Two commonly observed failure modes — center/off-center brittle interfacial cracking, and cohesive corner cracking — were looked at. The success of the modeling approach was evaluated by comparison with thermal impedance data, as well as with CSAM images showing the extent of cracking in the STIM. It is shown that the models agree qualitatively with experimental data, both in terms of failure locations, as well as in terms of rank ordering different packages in terms of STIM degradation.

A Sophisticated Method for Static Testing of TIM

2009 ◽  
Author(s):  
V. Sze´kely ◽  
G. Somlay ◽  
P. Szabo´ ◽  
E. Kolla´r ◽  
M. Rencz
Keyword(s):  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Static Testing ◽  
State Measurement ◽  
First Results ◽  
Measurement Principle ◽  
Interface Materials ◽  
Steady State Measurement ◽  
Better Than

Measuring the thermal resistance of thermal interface materials is an increasingly difficult task. The values to be measured are becoming smaller and smaller as a result of the huge efforts in material science to develop better thermal interface material in order to cope with the growing challenges of thermal management. In this paper we present the concept and some first results of a new TIM tester. The tester is using steady state measurement principle. With the help of dedicated test dies that are used to measure temperature, heat flux and parallelism at the same time, Rth values in the range of as low as 0.01 K/W can be measured with better than 5% accuracy.

scholarly journals Reliability Investigation of a Carbon Nanotube Array Thermal Interface Material

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2080 ◽  
Author(s):  
Andreas Nylander ◽  
Josef Hansson ◽  
Majid Kabiri Samani ◽  
Christian Chandra Darmawan ◽  
Ana Borta Boyon ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Thermal Performance ◽  
Photoelectron Spectroscopy ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Thermal Interface Resistance ◽  
Further Development ◽  
Interface Materials

As feature density increases within microelectronics, so does the dissipated power density, which puts an increased demand on thermal management. Thermal interface materials (TIMs) are used at the interface between contacting surfaces to reduce the thermal resistance, and is a critical component within many electronics systems. Arrays of carbon nanotubes (CNTs) have gained significant interest for application as TIMs, due to the high thermal conductivity, no internal thermal contact resistances and an excellent conformability. While studies show excellent thermal performance, there has to date been no investigation into the reliability of CNT array TIMs. In this study, CNT array TIMs bonded with polymer to close a Si-Cu interface were subjected to thermal cycling. Thermal interface resistance measurements showed a large degradation of the thermal performance of the interface within the first 100 cycles. More detailed thermal investigation of the interface components showed that the connection between CNTs and catalyst substrate degrades during thermal cycling even in the absence of thermal expansion mismatch, and the nature of this degradation was further analyzed using X-ray photoelectron spectroscopy. This study indicates that the reliability will be an important consideration for further development and commercialization of CNT array TIMs.

scholarly journals Non-Curing Thermal Interface Materials with Graphene Fillers for Thermal Management of Concentrated Photovoltaic Solar Cells

2019 ◽  
Vol 6 (1) ◽  
pp. 2 ◽  
Author(s):  
Barath Kanna Mahadevan ◽  
Sahar Naghibi ◽  
Fariborz Kargar ◽  
Alexander A. Balandin
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Thermal Management ◽  
Temperature Rise ◽  
Thermal Interface Material ◽  
Maximum Temperature ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Photovoltaic Solar Cells ◽  
Interface Materials

Temperature rise in multi-junction solar cells reduces their efficiency and shortens their lifetime. We report the results of the feasibility study of passive thermal management of concentrated multi-junction solar cells with the non-curing graphene-enhanced thermal interface materials. Using an inexpensive, scalable technique, graphene and few-layer graphene fillers were incorporated in the non-curing mineral oil matrix, with the filler concentration of up to 40 wt% and applied as the thermal interface material between the solar cell and the heat sink. The performance parameters of the solar cells were tested using an industry-standard solar simulator with concentrated light illumination at 70× and 200× suns. It was found that the non-curing graphene-enhanced thermal interface material substantially reduces the temperature rise in the solar cell and improves its open-circuit voltage. The decrease in the maximum temperature rise enhances the solar cell performance compared to that with the commercial non-cured thermal interface material. The obtained results are important for the development of the thermal management technologies for the next generation of photovoltaic solar cells.

Molecular Dynamics Simulations of Nanotube-Polymer Composites for Use as Thermal Interface Material

2003 ◽  
Author(s):  
S. Mahajan ◽  
G. Subbarayan ◽  
B. G. Sammakia ◽  
W. Jones
Keyword(s):  
Carbon Nanotube ◽  
Thermal Management ◽  
Cell Model ◽  
Thermal Interface Material ◽  
Design Parameters ◽  
Intermediate Step ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Scale Properties ◽  
Interface Materials

Thermal management in microelectronics is an important issue due to the projected increase in power dissipation in the electronic devices over the next 5–10 years. We seek a solution to this problem by exploring carbon nanotube-polymer matrix composites for use as thermal interface materials because of the reported high thermal conductivity and other remarkable thermal and mechanical properties of nanotubes. As an intermediate step to finding the composites’ conductivity, it is important to validate the use carbon nanotubes by calculating its diffusivity and conductivity first. This would facilitate later the estimating of important design parameters for thermal interface materials such as thermal diffusivity and conductivity. As polymer molecules are on the same size scale as nanotubes and the interaction at the polymer/nanotube interface is highly dependent on the molecular structure and bonding, Molecular Dynamic (MD) simulation is used to estimate the nano-scale properties. In this paper, until cell model consisting of a carbon nanotube was used and the diffusivity was measured. These findings would have implications in improving the thermal management efficiency and consequently improve the performance and reliability of future microelectronic devices.

Comparison between CNT Thermal Interface Materials with Graphene Thermal Interface Material in Term of Thermal Conductivity

2020 ◽  
Vol 1010 ◽  
pp. 160-165
Author(s):  
Mazlan Mohamed ◽  
Mohd Nazri Omar ◽  
Mohamad Shaiful Ashrul Ishak ◽  
Rozyanty Rahman ◽  
Nor Zaiazmin Yahaya ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Mixed Material ◽  
Interface Materials ◽  
Main Material

Thermal interface material (TIM) had been well conducted and developed by using several material as based material. A lot of combination and mixed material were used to increase thermal properties of TIM. Combination between materials for examples carbon nanotubes (CNT) and epoxy had had been used before but the significant of the studied are not exactly like predicted. In this studied, thermal interface material using graphene and CNT as main material were used to increase thermal conductivity and thermal contact resistance. These two types of TIM had been compare to each other in order to find wich material were able to increase the thermal conductivity better. The sample that contain 20 wt. %, 40 wt. % and 60 wt. % of graphene and CNT were used in this studied. The thermal conductivity of thermal interface material is both measured and it was found that TIM made of graphene had better thermal conductivity than CNT. The highest thermal conductivity is 23.2 W/ (mK) with 60 w. % graphene meanwhile at 60 w. % of CNT only produce 12.2 W/ (mK thermal conductivity).

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