Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892444
T. Nunnally, D. Pellicone, Nathan Van Velson, James Schmidt, T. Desai
A thermal model has been developed to simulate the performance of thermoelectric cooling for two avionics scenarios, where utilizing commercial off the shelf (COTS) components is highly desirable. Modeling predictions were validated through a series of experiments which studied the two scenarios at varying heat loads and heat sink thermal resistances. In these experiments, component temperatures were shown to be reduced by up to 15% with the addition of a thermoelectric cooler. Furthermore, in both scenarios, the model predicted the temperature of the cooled components within 3-10% accuracy. Further development of the model could result in a tool, which is not currently available, for optimizing system performance and determining the applicability of thermoelectric cooling in a given scenario.
{"title":"Thermoelectric performance model development and validation for a selection and design tool","authors":"T. Nunnally, D. Pellicone, Nathan Van Velson, James Schmidt, T. Desai","doi":"10.1109/ITHERM.2014.6892444","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892444","url":null,"abstract":"A thermal model has been developed to simulate the performance of thermoelectric cooling for two avionics scenarios, where utilizing commercial off the shelf (COTS) components is highly desirable. Modeling predictions were validated through a series of experiments which studied the two scenarios at varying heat loads and heat sink thermal resistances. In these experiments, component temperatures were shown to be reduced by up to 15% with the addition of a thermoelectric cooler. Furthermore, in both scenarios, the model predicted the temperature of the cooled components within 3-10% accuracy. Further development of the model could result in a tool, which is not currently available, for optimizing system performance and determining the applicability of thermoelectric cooling in a given scenario.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"75 1","pages":"1404-1411"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79613466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892443
K. Y. Lee, David B Brown, Satish Kumar
Thermoelectric generators (TEGs) can improve the net power consumption of electronic packages by generating power from the chip waste heat. In this study, a 3D computational model of electronic package with silicon nanowire (Si-NW) based embedded TEGs has been developed and the effect of crucial geometric parameters, contact resistances and thermal properties such as pitch length and length of Si-NWs, the electrical contact resistivity at Si-NW interface, thermal contact resistivity at TEG-package interface, and filling material thermal-conductivity on power generation has been evaluated. The analysis has shown how modifying some crucial parameters from their current values in different experimental studies affect power generation, e.g., decreasing the pitch length from 400 nm to 200 nm double the power generation, increasing the Si-NW length from 1 μm to 8 μm increases power generation by a factor of three and decreasing contact resistivity by one order of magnitude from 1.0×10-11 Ω-m2 enhances the power generation by a factor of two. This study has estimated the energy conversion efficiency of 0.02 % for 8 μm long Si-NWs using the best thermo-electric properties available from different experimental studies. Finally, the analysis provides insights into the crucial parameters of Si-NW TEGs which should be focus of the future studies.
{"title":"Performance evaluation of silicon nanowire arrays based thermoelectric generators","authors":"K. Y. Lee, David B Brown, Satish Kumar","doi":"10.1109/ITHERM.2014.6892443","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892443","url":null,"abstract":"Thermoelectric generators (TEGs) can improve the net power consumption of electronic packages by generating power from the chip waste heat. In this study, a 3D computational model of electronic package with silicon nanowire (Si-NW) based embedded TEGs has been developed and the effect of crucial geometric parameters, contact resistances and thermal properties such as pitch length and length of Si-NWs, the electrical contact resistivity at Si-NW interface, thermal contact resistivity at TEG-package interface, and filling material thermal-conductivity on power generation has been evaluated. The analysis has shown how modifying some crucial parameters from their current values in different experimental studies affect power generation, e.g., decreasing the pitch length from 400 nm to 200 nm double the power generation, increasing the Si-NW length from 1 μm to 8 μm increases power generation by a factor of three and decreasing contact resistivity by one order of magnitude from 1.0×10-11 Ω-m2 enhances the power generation by a factor of two. This study has estimated the energy conversion efficiency of 0.02 % for 8 μm long Si-NWs using the best thermo-electric properties available from different experimental studies. Finally, the analysis provides insights into the crucial parameters of Si-NW TEGs which should be focus of the future studies.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"4 1","pages":"1394-1403"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90715208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892304
S. Lei, K. Nolan
In this study, several 2D numerical simulations on a non-Newtonian flow over a confined cylinder placed in a rectangular microchannel are carried out at different Weissenberg (Wi) numbers. In particular, the Oldroyd-B model implemented in open source code OpenFOAM is employed to capture the three basic ingredients of polymer rheology, viz., anisotropy, elasticity and relaxation. Numerical calculations indicate that the flow structure particularly in the downstream is influenced by the presence of the cylinder. As Wi or the channel height increases, the velocity-recovery length required increases. It is observed that both the pressure drop across the channel and the elastic stress magnitude in the downstream grow exponentially with Wi. However it is interesting to observe that recirculation zones appear at Wi = 1.2 with a modest increase in pressure drop compared to Newtonian flow.
{"title":"Numerical simulations of viscoelastic flow over a confined cylinder in microchannels","authors":"S. Lei, K. Nolan","doi":"10.1109/ITHERM.2014.6892304","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892304","url":null,"abstract":"In this study, several 2D numerical simulations on a non-Newtonian flow over a confined cylinder placed in a rectangular microchannel are carried out at different Weissenberg (Wi) numbers. In particular, the Oldroyd-B model implemented in open source code OpenFOAM is employed to capture the three basic ingredients of polymer rheology, viz., anisotropy, elasticity and relaxation. Numerical calculations indicate that the flow structure particularly in the downstream is influenced by the presence of the cylinder. As Wi or the channel height increases, the velocity-recovery length required increases. It is observed that both the pressure drop across the channel and the elastic stress magnitude in the downstream grow exponentially with Wi. However it is interesting to observe that recirculation zones appear at Wi = 1.2 with a modest increase in pressure drop compared to Newtonian flow.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"41 1","pages":"369-373"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73526426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892328
M. González, Y. Kim
In this study, as a passive energy conversion/transport device, the performance of a pulsating heat pipe (PHP) using nanofluid is experimentally investigated. It has been suggested that nanofluids could improve the performance of wickless self-sustaining heat pipes. The transparent fused quartz tubing with 3 mm diameter is used to visualize the oscillations within the adiabatic section of the pipe. For the evaporator and condenser sections, copper tubing is used. A heater with a rating ranging from 20 to 120 Watts is used to provide the energy to the device along with some insulation to reduce the heat being lost to the environment. Two pressure transducers are used located in the evaporator and condenser section in order to record the pressure fluctuations. The operating temperature of the PHP varies from 30-100°C, with the power rates of 61 W and 119 W. The fill ratio of 30%, 50%, and 70% were tested. Several thermocouples along the pipe are used to measure the surface and fluid temperatures in order to calculate the heat transfer performance in the evaporator and condenser sections as well as the overall PHP performance.
{"title":"Experimental study of a pulsating heat pipe using nanofluid as a working fluid","authors":"M. González, Y. Kim","doi":"10.1109/ITHERM.2014.6892328","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892328","url":null,"abstract":"In this study, as a passive energy conversion/transport device, the performance of a pulsating heat pipe (PHP) using nanofluid is experimentally investigated. It has been suggested that nanofluids could improve the performance of wickless self-sustaining heat pipes. The transparent fused quartz tubing with 3 mm diameter is used to visualize the oscillations within the adiabatic section of the pipe. For the evaporator and condenser sections, copper tubing is used. A heater with a rating ranging from 20 to 120 Watts is used to provide the energy to the device along with some insulation to reduce the heat being lost to the environment. Two pressure transducers are used located in the evaporator and condenser section in order to record the pressure fluctuations. The operating temperature of the PHP varies from 30-100°C, with the power rates of 61 W and 119 W. The fill ratio of 30%, 50%, and 70% were tested. Several thermocouples along the pipe are used to measure the surface and fluid temperatures in order to calculate the heat transfer performance in the evaporator and condenser sections as well as the overall PHP performance.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"18 1","pages":"541-546"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78502222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892386
S. Weaver, G. Mandrusiak, N. Chen, O. Boomhower, J. Brewer, Robert A. Davis, R. Vetury, H. Henry
This paper describes a convection-based alternative to conduction heat spreaders that uses liquid microchannels to remove heat directly from the transistors. The concept connects microchannels etched directly into the die with a hydraulic circuit that includes a piezo-diaphragm pump, thermally-regulated autonomous flow control valves, and a high-efficiency heat exchanger to create a stand-alone, hermetically-sealed cooling module. The first part of the paper reviews the experiments performed to develop the key components in the cooling package. It describes the flow tests that measured the pressure drop characteristics of different microchannel designs, reviews the bench tests used to design the piezo-diaphragm pump, and discusses the process followed to train the shape-memory alloy used for the autonomous flow control valves. The second part presents micro Raman spectroscopy experiments that measured gate temperatures in energized GaN-on-SiC dies cooled by different microchannel designs. These measurements show that the microchannels enable up to a 50% increase in device input power over conventional conduction cooling with no increase in gate temperature. They also quantify how cooling effectiveness varies with channel geometry and show how thermal performance plateaus with increasing coolant flow rate.
{"title":"Experimental development of a near junction microchannel heat spreader","authors":"S. Weaver, G. Mandrusiak, N. Chen, O. Boomhower, J. Brewer, Robert A. Davis, R. Vetury, H. Henry","doi":"10.1109/ITHERM.2014.6892386","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892386","url":null,"abstract":"This paper describes a convection-based alternative to conduction heat spreaders that uses liquid microchannels to remove heat directly from the transistors. The concept connects microchannels etched directly into the die with a hydraulic circuit that includes a piezo-diaphragm pump, thermally-regulated autonomous flow control valves, and a high-efficiency heat exchanger to create a stand-alone, hermetically-sealed cooling module. The first part of the paper reviews the experiments performed to develop the key components in the cooling package. It describes the flow tests that measured the pressure drop characteristics of different microchannel designs, reviews the bench tests used to design the piezo-diaphragm pump, and discusses the process followed to train the shape-memory alloy used for the autonomous flow control valves. The second part presents micro Raman spectroscopy experiments that measured gate temperatures in energized GaN-on-SiC dies cooled by different microchannel designs. These measurements show that the microchannels enable up to a 50% increase in device input power over conventional conduction cooling with no increase in gate temperature. They also quantify how cooling effectiveness varies with channel geometry and show how thermal performance plateaus with increasing coolant flow rate.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"40 1","pages":"966-975"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75751407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892322
Munshi M. Basit, M. Motalab, J. Roberts, J. Suhling, P. Lall
In the electronic packaging industry, it is important to be able to make accurate predictions of board level solder joint reliability during thermal cycling exposures. The Anand viscoelastic constitutive model is often used to represent the material behavior of the solder in finite element simulations. This model is defined using nine material parameters, and the reliability prediction results are often highly sensitive to the Anand parameters. In this work, an investigation on the Anand constitutive model and its application to SAC solders of various Ag contents (i.e. SACN05, with N = 1, 2, 3, 4) has been performed. For each alloy, both water quenched (WQ) and reflowed (RF) solidification profiles were utilized to establish two unique specimen microstructures, and the same reflow profile was used for all four of the SAC alloys so that the results could be compared and the effects of Ag content could be studied systematically. The nine Anand parameters were determined for each unique solder alloy and microstructure from a set of stress-strain tests performed at several strain rates and temperatures. Testing conditions included strain rates of 0.001, 0.0001, and 0.00001 (sec-1), and temperatures of 25, 50, 75, 100, and 125 C. The Anand parameters were calculated from each set of stress-strain data using an established procedure that is described in detail in the paper. Using the calculated results for the various SAC alloys and microstructures, a set of empirical models have been established to describe the effects of SAC alloy Ag content on the Anand model parameters. As expected, the mechanical properties (modulus and strength) increase with the percentage of Ag content, and these changes strongly affect the Anand parameters. The sensitivity of the mechanical properties and Anand parameters to silver content is higher at lower silver percentages (1-2%). Also, the observed mechanical properties of water quenched samples were better (higher in magnitude) than the corresponding mechanical properties of the reflowed samples. Although the differences in elastic modulus between the water quenched and reflowed samples are small, significant differences are present for the yield and ultimate tensile stresses of all four SAC alloys. After deriving the Anand parameters for each alloy, the stress-strain curves have been calculated for various conditions, and excellent agreement was found between the predicted results and experimental stress-strain curves.
在电子封装行业中，能够在热循环暴露期间准确预测板级焊点可靠性是很重要的。在有限元模拟中，常采用Anand粘弹性本构模型来表征焊料的材料行为。该模型由9个材料参数定义，可靠性预测结果往往对Anand参数高度敏感。本文研究了Anand本构模型及其在不同Ag含量(即SACN05, N = 1,2,3,4)的SAC钎料中的应用。对于每种合金，采用水淬(WQ)和回流(RF)凝固曲线建立了两种独特的试样显微组织，并对所有四种SAC合金采用相同的回流曲线，以便对结果进行比较，并可以系统地研究Ag含量的影响。通过在不同应变速率和温度下进行的一组应力应变测试，确定了每种独特焊料合金的9个Anand参数和微观结构。测试条件包括应变率为0.001、0.0001和0.00001(秒-1)，温度为25、50、75、100和125℃。根据每组应力-应变数据，使用文中详细描述的既定程序计算Anand参数。利用对各种SAC合金和显微组织的计算结果，建立了一套经验模型来描述SAC合金Ag含量对Anand模型参数的影响。正如预期的那样，力学性能(模量和强度)随着Ag含量的增加而增加，这些变化强烈影响Anand参数。当银含量较低(1-2%)时，机械性能和Anand参数对银含量的敏感性较高。水淬试样的力学性能优于回流试样的力学性能(数量级更高)。尽管水淬和回流试样的弹性模量差异很小，但四种SAC合金的屈服应力和极限拉伸应力存在显著差异。在得到各合金的Anand参数后，计算了不同条件下的应力-应变曲线，预测结果与实验结果吻合较好。
{"title":"The effects of silver content and solidification profile on the Anand constitutive model for SAC lead free solders","authors":"Munshi M. Basit, M. Motalab, J. Roberts, J. Suhling, P. Lall","doi":"10.1109/ITHERM.2014.6892322","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892322","url":null,"abstract":"In the electronic packaging industry, it is important to be able to make accurate predictions of board level solder joint reliability during thermal cycling exposures. The Anand viscoelastic constitutive model is often used to represent the material behavior of the solder in finite element simulations. This model is defined using nine material parameters, and the reliability prediction results are often highly sensitive to the Anand parameters. In this work, an investigation on the Anand constitutive model and its application to SAC solders of various Ag contents (i.e. SACN05, with N = 1, 2, 3, 4) has been performed. For each alloy, both water quenched (WQ) and reflowed (RF) solidification profiles were utilized to establish two unique specimen microstructures, and the same reflow profile was used for all four of the SAC alloys so that the results could be compared and the effects of Ag content could be studied systematically. The nine Anand parameters were determined for each unique solder alloy and microstructure from a set of stress-strain tests performed at several strain rates and temperatures. Testing conditions included strain rates of 0.001, 0.0001, and 0.00001 (sec-1), and temperatures of 25, 50, 75, 100, and 125 C. The Anand parameters were calculated from each set of stress-strain data using an established procedure that is described in detail in the paper. Using the calculated results for the various SAC alloys and microstructures, a set of empirical models have been established to describe the effects of SAC alloy Ag content on the Anand model parameters. As expected, the mechanical properties (modulus and strength) increase with the percentage of Ag content, and these changes strongly affect the Anand parameters. The sensitivity of the mechanical properties and Anand parameters to silver content is higher at lower silver percentages (1-2%). Also, the observed mechanical properties of water quenched samples were better (higher in magnitude) than the corresponding mechanical properties of the reflowed samples. Although the differences in elastic modulus between the water quenched and reflowed samples are small, significant differences are present for the yield and ultimate tensile stresses of all four SAC alloys. After deriving the Anand parameters for each alloy, the stress-strain curves have been calculated for various conditions, and excellent agreement was found between the predicted results and experimental stress-strain curves.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"43 1","pages":"488-502"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73590723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892289
M. Shirazy, Stéphanie Allard, M. Beaumier, L. Fréchette
An experimental study is performed to characterize the effect of squeezing conditions on the particle distribution and bond line thickness of particle filled polymeric thermal interface materials (TIM). Two different commercial particle-filled polymeric TIMs with different particle volume fractions have been used in this study. Rheological properties such as yield stress and viscosity are measured experimentally. Using laser granulometry technique, particle sizes have been measured and are further confirmed by SEM imaging. The TIM is then deposited on circular copper samples and is squeezed with different pressing rates. Analyzing the samples by acoustic microscopy technique shows that at low pressing rates the particle distribution is not uniform and a TIM branching phenomena can be observed. At higher pressing rates, the final thickness of the bond line is approximately 30% higher than low velocity pressing rates. By keeping the load on the sample at the end of the pressing procedure the final BLT will continue to decrease. It can be concluded that the optimum condition of TIM dispense procedure should include a high velocity pressing rate to attain a uniform particle distribution followed by a constant load period to obtain the minimum BLT.
{"title":"Effect of squeezing conditions on the particle distribution and bond line thickness of particle filled polymeric thermal interface materials","authors":"M. Shirazy, Stéphanie Allard, M. Beaumier, L. Fréchette","doi":"10.1109/ITHERM.2014.6892289","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892289","url":null,"abstract":"An experimental study is performed to characterize the effect of squeezing conditions on the particle distribution and bond line thickness of particle filled polymeric thermal interface materials (TIM). Two different commercial particle-filled polymeric TIMs with different particle volume fractions have been used in this study. Rheological properties such as yield stress and viscosity are measured experimentally. Using laser granulometry technique, particle sizes have been measured and are further confirmed by SEM imaging. The TIM is then deposited on circular copper samples and is squeezed with different pressing rates. Analyzing the samples by acoustic microscopy technique shows that at low pressing rates the particle distribution is not uniform and a TIM branching phenomena can be observed. At higher pressing rates, the final thickness of the bond line is approximately 30% higher than low velocity pressing rates. By keeping the load on the sample at the end of the pressing procedure the final BLT will continue to decrease. It can be concluded that the optimum condition of TIM dispense procedure should include a high velocity pressing rate to attain a uniform particle distribution followed by a constant load period to obtain the minimum BLT.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"9 1","pages":"251-259"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84143529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892310
D. DeVoto, P. Paret, M. Mihalic, S. Narumanchi, A. Bar-Cohen, K. Matin
Thermal interface materials (TIMs) are an important enabler for low thermal resistance and reliable electronics packaging for a wide array of applications. There is a trend towards bonded interface materials (BIMs) because of their potential for low thermal resistance (<;1 mm2-K/W). However, due to coefficient of thermal expansion mismatches between various layers of a package, thermomechanical stresses are induced in BIMs and the package can be prone to failures and integrity risks. Deteriorated interfaces can result in high thermal resistance in the package and degradation and/or failure of the electronics. The Defense Advanced Research Projects Agency's (DARPA) Thermal Management Technologies (TMT) Program has addressed this challenge, supporting the development of mechanically compliant, low resistivity nano-thermal interface (NTI) materials. Prior development of these materials resulted in samples that met DARPA's initial thermal performance and synthesis metrics. In this present work, we describe the testing procedure and report the results of thermal performance and reliability characterization of an initial sample set of three different NTI-BIMs tested at the National Renewable Energy Laboratory.
{"title":"Thermal performance and reliability characterization of bonded interface materials (BIMs)","authors":"D. DeVoto, P. Paret, M. Mihalic, S. Narumanchi, A. Bar-Cohen, K. Matin","doi":"10.1109/ITHERM.2014.6892310","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892310","url":null,"abstract":"Thermal interface materials (TIMs) are an important enabler for low thermal resistance and reliable electronics packaging for a wide array of applications. There is a trend towards bonded interface materials (BIMs) because of their potential for low thermal resistance (<;1 mm2-K/W). However, due to coefficient of thermal expansion mismatches between various layers of a package, thermomechanical stresses are induced in BIMs and the package can be prone to failures and integrity risks. Deteriorated interfaces can result in high thermal resistance in the package and degradation and/or failure of the electronics. The Defense Advanced Research Projects Agency's (DARPA) Thermal Management Technologies (TMT) Program has addressed this challenge, supporting the development of mechanically compliant, low resistivity nano-thermal interface (NTI) materials. Prior development of these materials resulted in samples that met DARPA's initial thermal performance and synthesis metrics. In this present work, we describe the testing procedure and report the results of thermal performance and reliability characterization of an initial sample set of three different NTI-BIMs tested at the National Renewable Energy Laboratory.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"75 1","pages":"409-417"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85511309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892430
Xuhui Feng, C. King, D. DeVoto, M. Mihalic, S. Narumanchi
With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 μm bondline thickness) was 3 to 5 W/(m·K) and the contact resistance was 5 to 10 mm2·K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m·K) and the contact resistance was 2 to 5 mm2·K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.
{"title":"Investigation of thermal interface materials using phase-sensitive transient thermoreflectance technique","authors":"Xuhui Feng, C. King, D. DeVoto, M. Mihalic, S. Narumanchi","doi":"10.1109/ITHERM.2014.6892430","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892430","url":null,"abstract":"With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 μm bondline thickness) was 3 to 5 W/(m·K) and the contact resistance was 5 to 10 mm2·K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m·K) and the contact resistance was 2 to 5 mm2·K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"34 1 1","pages":"1296-1307"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83392362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892284
A. Reeser, A. Bar-Cohen, G. Hetsroni
We investigated two phase heat transfer in staggered and inline micro pin fin arrays, using deionized water and HFE-7200 as working fluids with exit qualities up to 90%,. The inline and staggered arrays have equivalent pin fin width of 153μm and height of 305μm on a heated base area of 0.96cm width by 2.88cm length. Mass fluxes ranged from 200 kg/m2s to 600 kg/m2s for HFE-7200 and 400 kg/m2s to 1300 kg/m2s for water. Base heat fluxes ranged from 27 W/cm2 to 118 W/cm2 for water, and 1 W/cm2 to 36 W/cm2 for HFE-7200. Average heat transfer coefficient data were obtained and successfully correlated to 3% MAE for water and 10-13% MAE for HFE-7200 in these pin fin arrays.
{"title":"High vapor quality two phase heat transfer in staggered and inline micro pin fin arrays","authors":"A. Reeser, A. Bar-Cohen, G. Hetsroni","doi":"10.1109/ITHERM.2014.6892284","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892284","url":null,"abstract":"We investigated two phase heat transfer in staggered and inline micro pin fin arrays, using deionized water and HFE-7200 as working fluids with exit qualities up to 90%,. The inline and staggered arrays have equivalent pin fin width of 153μm and height of 305μm on a heated base area of 0.96cm width by 2.88cm length. Mass fluxes ranged from 200 kg/m<sup>2</sup>s to 600 kg/m<sup>2</sup>s for HFE-7200 and 400 kg/m<sup>2</sup>s to 1300 kg/m<sup>2</sup>s for water. Base heat fluxes ranged from 27 W/cm<sup>2</sup> to 118 W/cm<sup>2</sup> for water, and 1 W/cm<sup>2</sup> to 36 W/cm<sup>2</sup> for HFE-7200. Average heat transfer coefficient data were obtained and successfully correlated to 3% MAE for water and 10-13% MAE for HFE-7200 in these pin fin arrays.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"1 1","pages":"213-221"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82969061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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