scholarly journals Fabrication of Al2O3/ZnO and Al2O3/Cu Reinforced Silicone Rubber Composite Pads for Thermal Interface Materials

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3259
Author(s):  
Seokkyu Jang ◽  
Eun Ji Choi ◽  
Han Jin Cheon ◽  
Won Il Choi ◽  
Woon Seo Shin ◽  
...  

Thermal interface materials (also known as thermal pads) are widely used as a crucial part to dissipate heat generated in miniaturized and integrated electronic components. Here, we systematically investigated the effects of small ceramic and metallic powders in rubbery thermal composite pads with a high content of aluminum oxide filler on the thermal conductivity of the composite pads. We optimized the compositions of aluminum oxide fillers with two different sizes in a polydimethylsiloxane (PDMS) matrix for rubbery composite pads with a high thermal conductivity. Based on the optimized compositions, zinc oxide powder or copper powder with an average size of 1 μm was used to replace 5 μm-sized aluminum oxide filler to examine the effects of the small ceramic and metallic powders, respectively, on the thermal conductivity of the composite pads. When zinc oxide powder was used as the replacement, the thermal conductivity of the rubbery composite pads decreased because more air bubbles were generated during the processing of the mixed paste with increased viscosity. On the other hand, when the copper powder was used as a replacement, a thermal conductivity of up to 2.466 W/m·K was achieved for the rubbery composite pads by optimizing the mixing composition. SEM images and EDS mapping confirmed that all fillers were evenly distributed in the rubbery composite pads.

Author(s):  
Vadim Gektin ◽  
Sai Ankireddi ◽  
Jim Jones ◽  
Stan Pecavar ◽  
Paul Hundt

Thermal Interface Materials (TIMs) are used as thermally conducting media to carry away the heat dissipated by an energy source (e.g. active circuitry on a silicon die). Thermal properties of these interface materials, specified on vendor datasheets, are obtained under conditions that rarely, if at all, represent real life environment. As such, they do not accurately portray the material thermal performance during a field operation. Furthermore, a thermal engineer has no a priori knowledge of how large, in addition to the bulk thermal resistance, the interface contact resistances are, and, hence, how much each influences the cooling strategy. In view of these issues, there exists a need for these materials/interfaces to be characterized experimentally through a series of controlled tests before starting on a thermal design. In this study we present one such characterization for a candidate thermal interface material used in an electronic cooling application. In a controlled test environment, package junction-to-case, Rjc, resistance measurements were obtained for various bondline thicknesses (BLTs) of an interface material over a range of die sizes. These measurements were then curve-fitted to obtain numerical models for the measured thermal resistance for a given die size. Based on the BLT and the associated thermal resistance, the bulk thermal conductivity of the TIM and the interface contact resistance were determined, using the approach described in the paper. The results of this study permit sensitivity analyses of BLT and its effect on thermal performance for future applications, and provide the ability to extrapolate the results obtained for the given die size to a different die size. The suggested methodology presents a readily adaptable approach for the characterization of TIMs and interface/contact resistances in the industry.


Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1201 ◽  
Author(s):  
Le Lv ◽  
Wen Dai ◽  
Aijun Li ◽  
Cheng-Te Lin

With the increasing power density of electrical and electronic devices, there has been an urgent demand for the development of thermal interface materials (TIMs) with high through-plane thermal conductivity for handling the issue of thermal management. Graphene exhibited significant potential for the development of TIMs, due to its ultra-high intrinsic thermal conductivity. In this perspective, we introduce three state-of-the-art graphene-based TIMs, including dispersed graphene/polymers, graphene framework/polymers and inorganic graphene-based monoliths. The advantages and limitations of them were discussed from an application point of view. In addition, possible strategies and future research directions in the development of high-performance graphene-based TIMs are also discussed.


2018 ◽  
Vol 7 (4.33) ◽  
pp. 530
Author(s):  
Mazlan Mohamed ◽  
Mohd Nazri Omar ◽  
Mohamad Shaiful Ashrul Ishak ◽  
Rozyanty Rahman ◽  
Zaiazmin Y.N ◽  
...  

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.  


Author(s):  
David Shaddock ◽  
Stanton Weaver ◽  
Ioannis Chasiotis ◽  
Binoy Shah ◽  
Dalong Zhong

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.


2006 ◽  
Vol 968 ◽  
Author(s):  
Yimin Zhang ◽  
Allison Xiao ◽  
Jeff McVey

ABSTRACTThermal interface materials (TIMs) are used to dissipate thermal energy from a heat-generating device to a heat sink via conduction. The growing power density of the electronic device demands next-generation high thermal conductivity and/or low thermal resistance TIMs. This paper discusses the current state-of-art TIM solutions, particularly fusible particles for improved thermal conductivity. The paper will address the benefits and limitations of this approach, and describe a system with unique filler morphology. Thermal resistance and diffusivity/conductivity characterization techniques are also discussed.


Author(s):  
Gary Lehmann ◽  
Hao Zhang ◽  
Arun Gowda ◽  
David Esler

Measurements and modeling of the thermal resistance of thin (< 100 microns) bond-lines are reported for composite thermal interface materials (TIMs). The composite TIMs consist of alumina particles dispersed in a polymer matrix to form six different adhesive materials. These model TIMs have a common matrix material and are distinguished by their particle size distributions. Bond-lines are formed in a three-layer assembly consisting of a substrate-TIM-substrate structure. The thermal resistance of the bond-line is measured, as a function of bond-line thickness, using the laser flash-technique. A linear variation of resistance with bond-line thickness is observed; Rbl = β · Lbl + Ro. A model is presented that predicts the effective thermal conductivity of the composite as a function of the particle and matrix conductivity, the particle-matrix surface conductance, the particle volume fraction and the particle size distribution. Specifically a method is introduced to account for a broad, continuous size distribution. A particle-matrix surface conductance value of ∼10W/mm2K is found to give good agreement between the measured and predicted effective thermal conductivity values of the composite TIMs.


2019 ◽  
Vol 21 (5) ◽  
pp. 2453-2462 ◽  
Author(s):  
Daewoo Suh ◽  
Sanghoon Lee ◽  
Chenchen Xu ◽  
Agha Aamir Jan ◽  
Seunghyun Baik

A percolation network of silver nanoflowers dramatically increased the thermal conductivity (42.4 W m−1 K−1) in soft polyurethane-matrix thermal interface materials.


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