Thermal interface materials based on graphene and silver nanopowder

Circuit World ◽  
2018 ◽  
Vol 44 (1) ◽  
pp. 16-20
Author(s):  
Piotr Sobik ◽  
Radoslaw Pawlowski ◽  
Bartlomiej Pawlowski ◽  
Boguslaw Drabczyk ◽  
Kazimierz Drabczyk
Keyword(s):  
Active Agent ◽  
Heat Removal ◽  
Ethylene Vinyl Acetate ◽  
Laser Flash ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Scanning Calorimetry ◽  
Thermal Interface ◽  
Content Type ◽  
Lamination Process

Purpose The purpose of this paper is to present results of the studies on modification of ethylene-vinyl acetate (EVA) encapsulation foil to be used as thermal interface material (TIM). It is estimated that poor thermal management in electronic devices can cause over 50 per cent of failures. As the junction temperature rises, the failure rate for electronics increases exponentially. To ensure sufficient heat transfer from its source, TIMs are used in various circuits. On the other hand, it is important to ensure high electric resistivity of the designed TIM. Design/methodology/approach The focus of the investigation was twofold: modification of EVA with both graphene oxide (GO) and silver nanopowder (nAg); and TIM applicability through lamination of photovoltaic cells with standard and modified EVA foil. The main problem of a new type of encapsulant is proper gas evacuation during the lamination process. For this reason, reference and modified samples were compared taking into account the percentage of gas bubbles in visible volume of laminated TIM. Finally, reference and modified TIM samples were compared using differential scanning calorimetry (DSC) and laser flash analysis (LFA) measurements. Findings The proper parameters of the lamination process for the modified EVA foil - with both GO and organometallic nAg particles - were selected. The nAg addition results in an increase in thermal conductivity of the proposed compositions with respect to unmodified EVA foil, which was confirmed by DSC and LFA measurements. Originality/value The experiments confirmed the potential application of both EVA foil as a matrix for TIM material and nAg with GO as an active agent. Proposed composition can bring additional support to a solar cell or other electronic components through effective heat removal, which increases its performance.

Impact of thermal interface material on luminous flux curve of InGaAlP low-power light-emitting diodes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muna E. Raypah ◽  
Mutharasu Devarajan ◽  
Shahrom Mahmud
Keyword(s):  
Low Power ◽  
Thermal Resistance ◽  
Thermal Management ◽  
Light Output ◽  
Luminous Flux ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Thermal Interface ◽  
Content Type ◽  
Thermally Conductive

Purpose One major problem in the lighting industry is the thermal management of the devices. Handling of thermal resistance from solder point to the ambiance of the light-emitting diode (LED) package is linked to the external thermal management that includes a selection of the cooling mode, design of heatsink/substrate and thermal interface material (TIM). Among the significant factors that increase the light output of the of the LED system are efficient substrate and TIM. In this work, the influence of TIM on the luminous flux performance of commercial indium gallium aluminium phosphide (InGaAlP) low-power (LP) LEDs was investigated. Design/methodology/approach One batch of LEDs was mounted directly onto substrates which were glass-reinforced epoxy (FR4) and aluminium-based metal-core printed circuit boards (MCPCBs) with a dielectric layer of different thermal conductivities. Another batch of LEDs was prepared in a similar way, but a layer of TIM was embedded between the LED package and substrate. The TIMs were thermally conductive epoxy (TCE) and thermally conductive adhesive (TCA). The LED parameters were measured by using the integrated system of thermal transient tester (T3Ster) and thermal-radiometric characterization of LEDs at various input currents. Findings With the employment of TIM, the authors found that the LED’s maximum luminous flux was significantly higher than the value mentioned in the LED datasheet, and that a significant reduction in thermal resistance and junction temperature was revealed. The results showed that for a system with low thermal resistance, the maximum luminous flux appeared to occur at a higher power level. It was found that the maximum luminous flux was 24.10, 28.40 and 36.00 lm for the LEDs mounted on the FR4 and two MCPCBs, respectively. After TCA application on the LEDs, the maximum luminous flux values were 32.70, 36.60 and 37.60 lm for the FR4 and MCPCBs, respectively. Moreover, the findings demonstrated that the performance of the LED mounted on the FR4 substrate was more affected by the employment of the TIM than that of MCPCBs. Research limitations/implications One of the major problems in the lighting industry is the thermal management of the device. In many low-power LED applications, the air gap between the two solder pads is not filled up. Heat flow is restricted by the air gap leading to thermal build-up and higher thermal resistance resulting in lower maximum luminous flux. Among the significant factors that increase the light output of the LED system are efficient substrate and TIM. Practical implications The findings in this work can be used as a method to improve thermal management of LP LEDs by applying thermal interface materials that can offer more efficient and brighter LP LEDs. Using aluminium-based substrates can also offer similar benefits. Social implications Users of LP LEDs can benefit from the findings in this work. Brighter automotive lighting (signalling and backlighting) can be achieved, and better automotive lighting can offer better safety for the people on the street, especially during raining and foggy weather. User can also use a lower LED power rating to achieve similar brightness level with LED with higher power rating. Originality/value Better thermal management of commercial LP LEDs was achieved with the employment of thermal interface materials resulting in lower thermal resistance, lower junction temperature and brighter LEDs.

Simulation of Nano Carbon Tube (NCT) in Thermal Interface Material for Electronic Packaging Application by Using CFD Software

2014 ◽  
Vol 803 ◽  
pp. 337-342 ◽  
Author(s):  
Mazlan Mohamed ◽  
A.M. Mustafa Al Bakri ◽  
Razak Wahab ◽  
A.K. Zulhisyam ◽  
A.M. Iqbal ◽  
...  
Keyword(s):  
Electronic Packaging ◽  
Material Selection ◽  
Three Dimensional ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Thermal Interface ◽  
Different Types ◽  
Fluent Software ◽  
Transfer Problems ◽  
Heat And Fluid Flow

This paper presents the nanocarbon tube in thermal interface material for electronic packaging application by using three dimensional numerical analysis of heat and fluid flow in computer. 3D model of electronic packaging is built using GAMBIT and simulated using FLUENT software. The study was made for a microprocessors arranged in line under different types of inlet velocities and package (chip) powers. The results are presented in terms of average junction temperature when chip powers have been increased from 2 W to 5 W. The junction temperature is been observed and it was found that the junction temperature of the electronic packaging using nanocarbon was able to wind stand the increasing in chip power from 2 W until 5 W. It also found that the material selection play important roles to control and manage the junction temperature. The strength of CFD software in handling heat transfer problems is proved to be excellent.

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.

Improvement of Thermal Conductivity of Silicone by Carbon Nanotube Array (CNTA)

2014 ◽  
Vol 1061-1062 ◽  
pp. 96-99 ◽  
Author(s):  
Liang Ke Wu ◽  
Ji Ying ◽  
Li Ting Chen
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Thermal Interface Material ◽  
Flash Method ◽  
Nanotube Array ◽  
Thermal Interface ◽  
Carbon Nanotube Array ◽  
Operating Temperatures

In order to improve the thermal conductivity of silicone, we prepared silicone/carbon nanotube array (CNTA) composite by immersing the CNTA into silicone solution and cured at 110 °C. The thermal conductivity of silicone and silicone/CNTA composite was measured by laser flash method at 30 °C, 60 °C, 90 °C, 120 °C, which are usually the operating temperatures. It was found that the thermal conductivity of silicone/CNTA composite increased with the temperature until achieved the plateau near 90 °C. The maximum thermal conductivity of silicone/CNTA composite is 0.674 W/mK, which is 220% higher than that of neat silicone. The excellent thermal conductivity makes the composite a promising thermal interface material.

Analysis On Thermal Behaviour Of The Sink And Die Area With Different Thermal Interface Material For High Power Light Emitting Diodes

2020 ◽  
pp. 116-126
Author(s):  
Debashis Raul ◽  
Kamalika Ghosh
Keyword(s):  
Light Emitting Diodes ◽  
Simulation Software ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Heating Process ◽  
Thermal Interface ◽  
Light Emitting ◽  
Materials Used ◽  
Comsol Simulation ◽  
Interface Materials

Its self-heating process directly affects the optical performance and reliability of light – emitting diodes (LEDs). It is important to disperse the generated heat from LED to surrounding atmosphere and keep the LED light performances same as declared by the manufacturer. Thermal interface material (TIM) is applied in between sink and source to reduce contact resistance at the junction between substrate and heat sink interface of the LED modules. This paper provides an assessment on ‘thermal interface materials’. Here different TIM materials used and the performance and problems of these commercial interface materials are discussed. From this study, one can calculate the temperature distribution in the sink area for different types of TIM materials under thermal conductivity perspective and be able to find the capability of dissipation of heat at the end surfaces of heat sinks, and design their system as well. In another process, TIMs with different thickness and input drive currents for the COB-based LED are investigated by using COMSOL simulation software. The results show that the junction temperature of the LED luminaire increases and reduce the lifetime when the input drive current and thickness of the TIM layers increase.

Experimental Study of VACNT Arrays as Thermal Interface Material

2013 ◽  
Author(s):  
Yulong Ji ◽  
Gen Li ◽  
Hongbin Ma ◽  
Yuqing Sun
Keyword(s):  
Thermal Conductivity ◽  
Chemical Vapor ◽  
Laser Flash ◽  
Thermal Interface Material ◽  
Chemical Vapor Deposition Method ◽  
Free Standing ◽  
Thermal Interface ◽  
Thermal Paste ◽  
Laser Flash Analysis ◽  
Contact Thermal Conductivity

In order to improve thermal interface material (TIM), vertically aligned carbon nanotube (VACNT) arrays were synthesized by the chemical vapor deposition method, and then transferred by dipping in hydrofluoric acid (HF acid) solution to get a free standing VACNT array. Different TIM samples with sandwiched structures were fabricated by inserting the free standing VACNT arrays between two copper plates with and without bonding materials. The laser flash analysis method was applied to measure the overall thermal conductivity of these samples. Results show that: compared with two copper plates in direct contact, thermal conductivity of samples only with VACNT arrays as TIM can be enhanced about 142%–460% depending on the thickness of VACNT arrays. Conventional TIM made up of thermal paste (TG-550 with thermal conductivity of 5 W/mK) and a thermal pad (TP-260 US with thermal conductivity of 6 W/mK) was used as a bonding material between copper plates and VACNT arrays, thermal conductivity has been shown to further improve with the highest values at 8.904 W/mK and 10.17 W/mK corresponding to the different bonding materials and different thicknesses of VACNT arrays used. Results also show that the thicker the VACNT array is when used as a TIM, the lower the overall thermal conductivity of the corresponding samples. This lower thermal conductivity caused by more defects in amorphous carbon of thicker VACNT arrays and lower density of the corresponding sandwiched samples.

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.

An Investigation of Spray Cooling Thermal Management for Semiconductor Burn-In

2003 ◽  
Author(s):  
T. Cader ◽  
B. Tolman ◽  
C. Tilton ◽  
M. C. Harris
Keyword(s):  
Thermal Management ◽  
Elevated Temperatures ◽  
Thermal Control ◽  
Spray Cooling ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Air Cooling ◽  
Thermal Interface ◽  
Thermoelectric Coolers ◽  
Thermal Solution

Semiconductor logic burn-in is a process during which potentially large quantities of devices are subjected to elevated temperatures and voltages in order to accelerate latent reliability defects and processing problems to failure prior to customer delivery. During burn-in, there is typically a large variation in the device power levels as well as a product-specific maximum burn-in temperature. Such variations result in a wide device temperature distribution (i.e., device temperature spread), which lowers the median allowable device temperature for the lot. Burn-in time is directly related to the median device temperature, in the sense that the lower the median temperature, the longer the required burn-in time. An optimum thermal management solution is one that is reliable, low-cost, enables a high median device temperature, and maximizes device throughput. Current thermal solutions include forced convection air-cooling, single-phase liquid-cooled heat sinks, and thermoelectric coolers. Some of the solutions employ thermal interface materials, as well as an active thermal control scheme for minimization of device temperature spread. All current solutions also employ an engage mechanism that places the thermal solution in contact with the device under test (DUT). The thermal solution at each DUT is typically gimbaled in an effort to ensure uniform contact pressure between the cooling head and device. The present study deals with the application of direct spray cooling of semiconductor devices undergoing burn-in: this approach negates the need for an actuation mechanism and thermal interface material, is capable of reduced junction temperature spread via active thermal control, and results in reduced across device temperature “gradients”. A spray cooled burn-in slot level prototype was built to accommodate single burn-in boards for bare DUTs as well as small and large lidded DUTs. The solution was investigated primarily for thermal capability and device-to-device junction temperature spread, but results were also obtained for on-DUT thermal “gradients”. For the specific test conditions selected, the heat flux removal capability demonstrated was 146W/cm2 for the bare DUT, 136W/cm2 for the small lidded DUT, and 63W/cm2 for the large lidded DUT. For each DUT investigated, and through the use of active flow control, the device temperature spread between two devices running at a 50% difference in power levels was shown to be less than 1°C.

Comparison between Thermal Interface Materials Made of Nano Carbon Tube (NCT) with Gad Pad 2500 in Term of Junction Temperature by Using CFD Software, FluentTM

2014 ◽  
Vol 803 ◽  
pp. 243-249
Author(s):  
Mazlan Mohamed ◽  
A.M. Mustafa Al Bakri ◽  
Razak Wahab ◽  
A.K. Zulhisyam ◽  
M.R. Mohd Sukhairi ◽  
...  
Keyword(s):  
Electronic Packaging ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Carbon Tube ◽  
Different Types ◽  
Fluent Software ◽  
Nano Carbon ◽  
Interface Materials

This paper presents the comparison between thermal interface materials made of nano carbon tube (NCT) with Gad Pad 2500 in term of junction temperature by using CFD Software, FluentTM. 3D model of electronic packaging is built using GAMBIT and simulated using FLUENT software. The study was made for a microprocessors arranged in line under different types of inlet velocities and package (chip) powers. The results are presented in terms of average junction temperature when chip powers have been increased from 0.5 W to 2 W. The junction temperature is been observed and it was found that the junction temperature of the electronic packaging using nano carbon has lower junction temperature compare to the Gad Pad 2500. It also found that the NCT was able to reduce the junction temperature up to 20-30% compare to others thermal interface material.

Sign in / Sign up

Export Citation Format

Share Document