Synthesis and Thermal Analysis of Vertically Aligned CNTs Grown on Copper Substrates

MRS Advances ◽  
2017 ◽  
Vol 2 (58-59) ◽  
pp. 3657-3662
Author(s):  
Qiuhong Zhang ◽  
Levi Elston
Keyword(s):  
Thermal Resistance ◽  
Thermal Contact ◽  
Laser Flash ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Significant Research ◽  
Vertically Aligned ◽  
Array Density ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

Due to the low degree of contact area and weak interfacial adhesion between CNTs and the growth substrate (Cu), large thermal contact resistance is the largest challenge preventing the use of vertically aligned CNTs (VACNTs) as a thermal interface material (TIM). Although significant research has been done regarding the growth of CNTs on reactive substrates by using an appropriate buffer layer in this group’s previous work, there are many unanswered questions associated with using VACNTs as a thermal interface material beyond synthesis. This effort extends prior work on carbon nanotube growth, by concentrating on ways to evaluate/measure CNT-based nanocomposite thermal resistance. In this study, with the use of a laser flash measurement system, the influence of CNT array properties (layer height and density) on the thermal diffusivity and thermal resistance of the CNT composite were investigated. Test results identify a correlation between the CNT array density/thickness and its thermal resistance.

Thermal Resistance Analysis of Sn-Bi Solder Paste Used as Thermal Interface Material for Power Electronics Applications

2014 ◽  
Vol 136 (1) ◽  
Author(s):  
Rui Zhang ◽  
Jian Cai ◽  
Qian Wang ◽  
Jingwei Li ◽  
Yang Hu ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Power Electronics ◽  
Heat Dissipation ◽  
Laser Flash ◽  
Acoustic Microscopy ◽  
Thermal Interface Material ◽  
Solder Paste ◽  
Good Reliability ◽  
Thermal Interface ◽  
Power Modules

To promote heat dissipation in power electronics, we investigated the thermal conduction performance of Sn-Bi solder paste between two Cu plates. We measured the thermal resistance of Sn-Bi solder paste used as thermal interface material (TIM) by laser flash technique, and a thermal resistance less than 5 mm2 K/W was achieved for the Sn-Bi TIM. The Sn-Bi solder also showed a good reliability in terms of thermal resistance after thermal cycling, indicating that it can be a promising candidate for the TIM used for power electronics applications. In addition, we estimated the contact thermal resistance at the interface between the Sn-Bi solder and the Cu plate with the assistance of scanning acoustic microscopy. The experimental data showed that Sn-Bi solder paste could be a promising adhesive material used to attach power modules especially with a large size on the heat sink.

Modeling and Experimental Characterization of Metal Microtextured Thermal Interface Materials

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
R. Kempers ◽  
A. M. Lyons ◽  
A. J. Robinson
Keyword(s):  
Thermal Resistance ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Small Scale ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Main Challenge

A metal microtextured thermal interface material (MMT-TIM) has been proposed to address some of the shortcomings of conventional TIMs. These materials consist of arrays of small-scale metal features that plastically deform when compressed between mating surfaces, conforming to the surface asperities of the contacting bodies and resulting in a low-thermal resistance assembly. The present work details the development of an accurate thermal model to predict the thermal resistance and effective thermal conductivity of the assembly (including contact and bulk thermal properties) as the MMT-TIMs undergo large plastic deformations. The main challenge of characterizing the thermal contact resistance of these structures was addressed by employing a numerical model to characterize the bulk thermal resistance and estimate the contribution of thermal contact resistance. Furthermore, a correlation that relates electrical and thermal contact resistance for these MMT-TIMs was developed that adequately predicted MMT-TIM properties for several different geometries. A comparison to a commercially available graphite TIM is made as well as suggestions for optimizing future MMT-TIM designs.

Maximum Resolution of a Probe-Based, Steady-State Thermal Interface Material Characterization Instrument

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Ronald J. Warzoha ◽  
Andrew N. Smith ◽  
Maurice Harris
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
High Performance ◽  
Heat Dissipation ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Interfacial Thermal Resistance ◽  
Uniform Heat Flux ◽  
Thermal Probe ◽  
Thermal Interface

Thermal interface materials (TIMs) constitute a critical component for heat dissipation in electronic packaging systems. However, the extent to which a conventional steady-state thermal characterization apparatus can resolve the interfacial thermal resistance across current high-performance interfaces (RT < 1 mm2⋅K/W) is not clear. In this work, we quantify the minimum value of RT that can be measured with this instrument. We find that in order to increase the resolution of the measurement, the thermal resistance through the instrument's reference bars must be minimized relative to RT. This is practically achieved by reducing reference bar length. However, we purport that the minimization of reference bar length is limited by the effects of thermal probe intrusion along the primary measurement pathway. Using numerical simulations, we find that the characteristics of the probes and surrounding filler material can significantly impact the measurement of temperature along each reference bar. Moreover, we find that probes must be spaced 15 diameters apart to maintain a uniform heat flux at the interface, which limits the number of thermal probes that can be used for a given reference bar length. Within practical constraints, the minimum thermal resistance that can be measured with an ideal instrument is found to be 3 mm2⋅K/W. To verify these results, the thermal resistance across an indium heat spring material with an expected thermal contact resistance of ∼1 mm2⋅K/W is experimentally measured and found to differ by more than 100% when compared to manufacturer-reported values.

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.

Characterization of a Liquid-Metal Micro Droplets Thermal Interface Material

2010 ◽  
Author(s):  
Amer M. Hamdan ◽  
Aric R. McLanahan ◽  
Robert F. Richards ◽  
Cecilia D. Richards
Keyword(s):  
Liquid Metal ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Applied Load ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Thermal Interface Resistance ◽  
Droplet Array

This work presents the characterization of a thermal interface material consisting of an array of mercury micro droplets deposited on a silicon die. Three arrays were tested, a 40 × 40 array (1600 grid) and two 20 × 20 arrays (400 grid). All arrays were assembled on a 4 × 4 mm2 silicon die. An experimental facility which measures the thermal resistance across the mercury array under steady state conditions is described. The thermal interface resistance of the arrays was characterized as a function of the applied load. A thermal interface resistance as low as 0.253 mm2 K W−1 was measured. A model to predict the thermal resistance of a liquid-metal micro droplet array was developed and compared to the experimental results. The model predicts the deformation of the droplet array under an applied load and then the geometry of the deformed droplets is used to predict the thermal resistance of the array. The contact resistance of the mercury arrays was estimated based on the experimental and model data. An average contact resistance was estimated to be 0.14 mm2 K W−1.

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.  

scholarly journals Demonstration of a Compliant Micro-Spring Array As a Thermal Interface Material for Pluggable Optoelectronic Transceiver Modules

2019 ◽  
Author(s):  
Jin Cui ◽  
Liang Pan ◽  
Justin A. Weibel
Keyword(s):  
Heat Sink ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Thermal Interface Material ◽  
Thermal Contact Conductance ◽  
Compression Pressure ◽  
Thermal Interface ◽  
Operation Temperature ◽  
Optical Module ◽  
Dry Contact

Abstract Pluggable optoelectronic transceiver modules are widely used in the fiber-optic communication infrastructure. It is essential to mitigate thermal contact resistance between the high-power optical module and its riding heat sink in order to maintain the required operation temperature. The pluggable nature of the modules requires dry contact thermal interfaces that permit repeated insertion–disconnect cycles under low compression pressures (∼10–100 kPa). Conventional wet thermal interface materials (TIM), such as greases, or those that require high compression pressures, are not suitable for pluggable operation. Here we demonstrate the use of compliant micro-structured TIM to enhance the thermal contact conductance between an optical module and its riding heat sink under a low compression pressure (20 kPa). The metallized and polymer-coated structures are able to accommodate the surface nonflatness and microscale roughness of the mating surface while maintaining a high effective thermal conductance across the thickness. This dry contact TIM is demonstrated to maintain reliable thermal performance after 100 plug-in and plug-out cycles while under compression.

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.

Packaging of High Power UV-LED Modules on Ceramic and Aluminum Substrates

2012 ◽  
Vol 2012 (1) ◽  
pp. 000225-000232 ◽  
Author(s):  
Marc Schneider ◽  
Benjamin Leyrer ◽  
Christian Herbold ◽  
Stefan Maikowske
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Input Power ◽  
Thermal Interface Material ◽  
Maximum Temperature ◽  
Thermal Interface ◽  
Uv Led ◽  
Forward Current ◽  
Water Cooler ◽  
Forced Air

An LED module consisting of 98 UV-LEDs with an emission wavelength of 395 nm placed on a ceramic substrate of 211 mm2 is presented. The module is cooled by a forced air heat sink as well as a high performance microstructured water cooler to lower the thermal resistance. For high thermal conductance a liquid metal as the thermal interface material between substrate and heat sink is used. With the forced air heat sink a maximum irradiance of 27.3 W/cm2 at a forward current of 700 mA and 220 W electrical input power was achieved. The microstructured water cooler enabled an almost doubling of the electrical input power (430 W) while maintaining the chip's maximum temperature. For a reduction of the module's thermal resistance a thick film process for aluminum sheet metal substrates was developed. A prototype LED module with 25 UV-LED chips on an area of 54 mm2 achieved a maximum optical power density of 31.6 W/cm2 at a forward current of 900 mA using a forced air heat sink. For an improved cooling of the LED chips a chip-on-heat sink-technology with embedded water cooling channels is developed to eliminate the thermal interface between substrate and heat sink.

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