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.

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.

Design and Validation of a High-Temperature Thermal Interface Resistance Measurement System

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Menglong Hao ◽  
Kimberly R. Saviers ◽  
Timothy S. Fisher
Keyword(s):  
Surface Roughness ◽  
Measurement Accuracy ◽  
Heat Losses ◽  
Thermal Interface Material ◽  
Interface Temperature ◽  
Test Apparatus ◽  
Graphite Foil ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Thermal Interface Resistance

In order to measure thermal interface resistance (TIR) at temperatures up to 700 °C, a test apparatus based on two copper 1D reference bars has been developed. Design details are presented with an emphasis on how the system minimizes the adverse effects of heat losses by convection and radiation on measurement accuracy. Profilometer measurements of the contacting surface are presented to characterize surface roughness and flatness. A Monte Carlo method is applied to quantify experimental uncertainties, resulting in a standard deviation of thermal resistance as low as 2.5 mm2 K/W at 700 °C. In addition, cyclic measurements of a standard thermal interface material (TIM) sample (graphite foil) are presented up to an interface temperature of 400 °C. The interface resistance results range between approximately 40 and 100 mm2 K/W. Further, a bare Cu–Cu interface is evaluated at several interface temperatures up to 700 °C.

Characterization of a liquid–metal microdroplet thermal interface material

2011 ◽  
Vol 35 (7) ◽  
pp. 1250-1254 ◽  
Author(s):  
A. Hamdan ◽  
A. McLanahan ◽  
R. Richards ◽  
C. Richards
Keyword(s):  
Liquid Metal ◽  
Thermal Interface Material ◽  
Thermal Interface

Characterization of Thermal Contact Resistance Doped with Thermal Interface Material

2013 ◽  
Vol 30 (9) ◽  
pp. 943-950 ◽  
Author(s):  
Iswor Bajracharya ◽  
Yoshimi Ito ◽  
Wataru Nakayama ◽  
Byeong-Jun Moon ◽  
Sun-Kyu Lee
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Thermal Interface

Investigation on Carbon Nanotubes as Thermal Interface Material Bonded With Liquid Metal Alloy

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Yulong Ji ◽  
Gen Li ◽  
Chao Chang ◽  
Yuqing Sun ◽  
Hongbin Ma
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Liquid Metal ◽  
Thermal Resistance ◽  
Plasma Treatment ◽  
Contact Surface ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Bonding Material ◽  
Liquid Metal Alloy

Vertically aligned carbon nanotube (VACNT) films with high thermal conductance and mechanical compliance offer an attractive combination of properties for thermal interface applications. In current work, VACNT films synthesized by the chemical vapor deposition method were used as thermal interface material (TIM) and investigated experimentally. The liquid metal alloy (LMA) with melting point of 59 °C was used as bonding material to attach VACNT films onto copper plates. In order to enhance the contact area of LMA with the contact surface, the wettability of the contact surface was modified by plasma treatment. The thermal diffusivity, thermal conductivity, and thermal resistance of the synthesized samples were measured and calculated by the laser flash analysis (LFA) method. Results showed that: (1) VACNT films can be used as TIM to enhance the heat transfer performance of the contact surface; (2) the LMA can be used as bonding material, and its performance is dependent on the LMA wettability on the contact surface. (3) When applying VACNT film as the TIM, LMA is used as the bonding material. After plasma treatment, comparison of VACNT films with the dry contact between copper and silicon showed that thermal diffusivity can be increased by about 160%, the thermal conductivity can be increased by about 100%, and the thermal resistance can be decreased by about 31%. This study shows the advantages of using VACNT films as TIMs in microelectronic packaging.

Fabrication and Characterization of a Liquid-Metal Micro-Droplet Array for Use as a Thermal Switch

2003 ◽  
Author(s):  
A. O. Christensen ◽  
J. P. Jacob ◽  
C. D. Richards ◽  
D. F. Bahr ◽  
R. F. Richards
Keyword(s):  
Liquid Metal ◽  
Silicon Substrate ◽  
Applied Load ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Switch ◽  
Droplet Array ◽  
Fabrication And Characterization ◽  
Predicted Values

This paper presents the development of a liquid metal micro-droplet array for use as a thermal switch. A method of producing arrays of mercury micro-droplets on a silicon substrate, which is compatible with batch manufacturing, is detailed. A technique for examining the deformation of the micro-droplets under an applied load is offered. For 30μm diameter droplets under deformation, contact diameters ranging from 0–30μm, and forces of 0–0.10mN are examined. Predicted values of thermal contact resistance as a function of applied load to the switch are given, indicating that a thermal switch whose thermal resistance changes by a factor of ten could be fabricated.

Improving the Resolution of Steady-State, Infrared-Based Thermal Interface Resistance Measurements Using High-Precision Metrology to Determine In-Situ TIM Thickness

2016 ◽  
Author(s):  
Ronald J. Warzoha ◽  
Andrew N. Smith ◽  
Maurice Harris
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Interfacial Thermal Resistance ◽  
Thermal Probe ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Measurement Systems ◽  
Thermal Interface Resistance ◽  
Order Of Magnitude

The performance characteristics of thermal interface materials (TIMs) are quickly outpacing our ability to measure them using steady-state techniques. In fact, scientists have turned to photothermal techniques like Time-domain Thermoreflectance (TDTR) to measure the impedance to heat flow across TIMs, namely due to their relatively low measurement uncertainties. However, such techniques are costly, require significant sample preparation, only measure local thermal impedances and are not yet equipped to measure thermal resistance as a function of pressure. Instead, it is desirable to maximize the resolution of traditional steady-state equipment for these types of measurements. In this work, we develop a more robust and accurate methodology to determine the temperature difference across the junction of a traditional steady-state apparatus using high accuracy measurements of in-situ TIM thickness in tandem with infrared thermography. This methodology eliminates a significant fraction of the uncertainty associated with the measurement of thermal interface resistance. Importantly, the use of this method improves the accuracy of the measurement device by an order of magnitude at interfacial thermal resistance values on the order of 1·10−6m2·K/W when compared to state-of-the-art, thermal probe-based measurement systems.

Liquid metal nano/micro-channels as thermal interface materials for efficient energy saving

2018 ◽  
Vol 6 (39) ◽  
pp. 10611-10617 ◽  
Author(s):  
Liuying Zhao ◽  
Huiqiang Liu ◽  
Xuechen Chen ◽  
Sheng Chu ◽  
Han Liu ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Thermal Resistance ◽  
Thermal Management ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Efficient Energy ◽  
Micro Channels ◽  
High Elasticity ◽  
Interface Materials

Thermal interface material (TIMs) pads/sheets with both high elasticity and low thermal resistance are indispensable components for thermal management.

Evaluation of a Thermal Interface Material Fabricated Using Thermocompression Bonding of Carbon Nanotube Turf

2009 ◽  
Author(s):  
Amer M. Hamdan ◽  
Jeong H. Cho ◽  
Ryan D. Johnson ◽  
David F. Bahr ◽  
Robert F. Richards ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Thermal Interface Material ◽  
Silicon Substrates ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Full Coverage ◽  
Thermal Interface Resistance ◽  
Thermocompression Bonding ◽  
Interface Materials

In this work, the use of vertically aligned carbon nanotubes (VACNTs) as thermal interface materials is presented. The VACNT structure is fabricated on 4×4 mm silicon substrates using chemical vapor deposition (CVD). These VACNT structures can be transferred to other substrates using a thermocompression bonding process; the process transfers the VACNTs to metalized silicon die which are tested after that as thermal interface materials. Two configurations of VACNTs were tested: one with a full coverage of VACNTs and one with patterned VACNTs. For the full coverage turf a thermal interface resistance as low as 1.082 cm2K/W was obtained, while a thermal interface resistance of 0.044 cm2K/W was obtained for the patterned turfs.

Very High Performance Thermal Interface Material and Attachment Technology

2003 ◽  
Author(s):  
Ralph L. Webb ◽  
Jin Wook Paek ◽  
David Pickrell
Keyword(s):  
Thermal Conductivity ◽  
Thermal Degradation ◽  
Contact Resistance ◽  
High Performance ◽  
Copper Substrate ◽  
Alloy Layer ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Penn State

This paper provides an update on work at Penn State University on advanced thermal interface material (TIM) and attachment technology. The TIM concept consists of a “Low Melting Temperature Alloy” (LMTA) bonded to a thin copper substrate. The present work includes analytical modeling to separate the interface resistance (Rint) into “material” and “contact” resistance. Modeling indicates that contact resistance accounts for 1/3 of the interface resistance (Rint). Additional alloys have been identified that have thermal conductivity approximately three-times those identified in the previous 2002 publication. Thermal degradation of the LMTA TIM was also observed in the present work after extended thermal cycling above the melting point of the alloy. Possible mechanisms for this degradation are oxidation and contamination of the alloy layer rather than the inter-metallic diffusion. Use of the high thermal conductivity alloys, and soldered contact surfaces will provide very low Rint as well as minimizing the thermal degradation. It appears that Rint as small as, or less than, 0.005 cm2-K/W may be possible. Description of the modified Penn State TIM tester is provided, which will allow measurement of Rint = 0.01 cm2-K/W with less than 30% error.

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