Pub Date : 2014-05-27DOI: 10.1109/ITHERM.2014.6892379
S. Thirugnanasambandam, T. Sanders, A. Raj, D. Stone, John L. Evans, G. Flowers, J. Suhling
Relatively little is known about the performance of the doped Ball Grid Array (BGA) packages used in semiconductor industries, even though newer products are widely being introduced to the market. This work experimentally investigates the doping effects of the BGA packages with SAC 305 alloys, caused by the vibration loading. This experiment focuses on the vibration fatigue life of 15 mm CABGA packages with 208 perimeter solder balls on a 0.8 mm pitch. The test boards were built to withstand JEDEC JESD22-B103B standards of high stress test in vibrational shaker table to assess the solder joint performance. The test boards are built with three different reflow profiles and two different stencil thicknesses 8 mil (6 mil with overprint) and 4 mil to study the differences in doping effect of the new doped alloys. The WLCSP assembly was subjected to accelerated life test of severe random vibration per board. The reliability of the component is determined by the ability of the components to withstand vibration as a result of motion produced by field operations. The deleterious effect of the mechanical loading of BGA's on the characteristic fatigue lifetime is reported. The results show that the material characteristics has a direct impact on the total time to failure. The results show that the Time-To-Failure (TTF) of the solder joint decreases with doping. The effectiveness of this characteristics was demonstrated with promising results through vibration testing of different lead free low creep alloys. This paper concludes with discussion of the deterioration intensity aging has on SAC alloys and the change in reliability due to doping.
相对而言，人们对半导体工业中使用的掺杂球栅阵列(BGA)封装的性能知之甚少，尽管更新的产品正在广泛引入市场。本文通过实验研究了振动载荷对SAC 305合金的掺杂效应。本实验主要研究了在0.8 mm间距上使用208个周长焊接球的15 mm CABGA封装的振动疲劳寿命。测试板的制造符合JEDEC JESD22-B103B标准的振动台高应力测试，以评估焊点性能。采用三种不同的回流型和两种不同的模板厚度(8mil(套印6mil)和4mil)制作测试板，研究新掺杂合金的掺杂效果差异。对WLCSP组件进行了各板剧烈随机振动加速寿命试验。组件的可靠性取决于组件承受由现场作业产生的运动引起的振动的能力。报道了BGA的机械载荷对其特征疲劳寿命的有害影响。结果表明，材料特性对总失效时间有直接影响。结果表明，焊点的失效时间随掺杂量的增加而减小。通过对不同无铅低蠕变合金的振动试验，验证了该特性的有效性，并取得了良好的结果。最后讨论了掺杂对SAC合金的劣化、强度老化和可靠性的影响。
{"title":"The study of vibrational performance on different doped low creep lead free solder paste and solder ball grid array packages","authors":"S. Thirugnanasambandam, T. Sanders, A. Raj, D. Stone, John L. Evans, G. Flowers, J. Suhling","doi":"10.1109/ITHERM.2014.6892379","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892379","url":null,"abstract":"Relatively little is known about the performance of the doped Ball Grid Array (BGA) packages used in semiconductor industries, even though newer products are widely being introduced to the market. This work experimentally investigates the doping effects of the BGA packages with SAC 305 alloys, caused by the vibration loading. This experiment focuses on the vibration fatigue life of 15 mm CABGA packages with 208 perimeter solder balls on a 0.8 mm pitch. The test boards were built to withstand JEDEC JESD22-B103B standards of high stress test in vibrational shaker table to assess the solder joint performance. The test boards are built with three different reflow profiles and two different stencil thicknesses 8 mil (6 mil with overprint) and 4 mil to study the differences in doping effect of the new doped alloys. The WLCSP assembly was subjected to accelerated life test of severe random vibration per board. The reliability of the component is determined by the ability of the components to withstand vibration as a result of motion produced by field operations. The deleterious effect of the mechanical loading of BGA's on the characteristic fatigue lifetime is reported. The results show that the material characteristics has a direct impact on the total time to failure. The results show that the Time-To-Failure (TTF) of the solder joint decreases with doping. The effectiveness of this characteristics was demonstrated with promising results through vibration testing of different lead free low creep alloys. This paper concludes with discussion of the deterioration intensity aging has on SAC alloys and the change in reliability due to doping.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"19 1","pages":"920-923"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82164740","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.2014.6892331
Xiaojin Wei, G. Goth, P. Kelly, R. Zoodsma, A. VanDeventer
Air-water hybrid cooling offers flexible design choices for computer systems with components of different thermal management needs. On one hand, water cooling enables the continuous growth of CPU performance and increasing packaging density. High performance cold plates such as microchannels have been successfully implemented for water cooling in previous high-end systems. When coupled with an air-water heat exchanger or radiator, the water loop becomes a closed one with no need for facility chilled water. This significantly reduces the complexity to deploy the server in the data center. On the other hand, for components with less thermal demand, traditional air-cooling technology is adequate with low cost, high availability and better serviceability. For the computer system as a whole, an air-water hybrid cooling system may be optimized. Such a hybrid system typically requires pumps to drive the water loops, air-movers to drive air through the radiator and blowers or fans to drive the air flow for component cooling. It is the focus of this paper to study the optimum allocation of energy between the pumps and air-movers for a given total cooling energy budget and overall load. The goals are to achieve better overall thermal performance and to reduce the cooling energy consumption. To this end models for each cooling block are established based on test data. These include the air-water heat exchanger, pumps, blowers, and cold plates. These models are linked together to predict the overall thermal system operating points for different application scenarios. A parametric study is then conducted to define the near optimum allocation of cooling energy for these scenarios that meets the thermal design objectives. Additionally, sub-threshold leakage for the CPU is taken into account to enhance the model since temperature provides positive feedback. It is shown through modeling that additional performance enhancement is possible with judicious allocation of cooling energy for a given overall energy budget. It is argued in this paper that overall energy efficiency can be improved significantly through intelligent data driven energy allocation.
{"title":"Air-water hybrid cooling for computer servers: A case study for optimum cooling energy allocation","authors":"Xiaojin Wei, G. Goth, P. Kelly, R. Zoodsma, A. VanDeventer","doi":"10.1109/ITHERM.2014.6892331","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892331","url":null,"abstract":"Air-water hybrid cooling offers flexible design choices for computer systems with components of different thermal management needs. On one hand, water cooling enables the continuous growth of CPU performance and increasing packaging density. High performance cold plates such as microchannels have been successfully implemented for water cooling in previous high-end systems. When coupled with an air-water heat exchanger or radiator, the water loop becomes a closed one with no need for facility chilled water. This significantly reduces the complexity to deploy the server in the data center. On the other hand, for components with less thermal demand, traditional air-cooling technology is adequate with low cost, high availability and better serviceability. For the computer system as a whole, an air-water hybrid cooling system may be optimized. Such a hybrid system typically requires pumps to drive the water loops, air-movers to drive air through the radiator and blowers or fans to drive the air flow for component cooling. It is the focus of this paper to study the optimum allocation of energy between the pumps and air-movers for a given total cooling energy budget and overall load. The goals are to achieve better overall thermal performance and to reduce the cooling energy consumption. To this end models for each cooling block are established based on test data. These include the air-water heat exchanger, pumps, blowers, and cold plates. These models are linked together to predict the overall thermal system operating points for different application scenarios. A parametric study is then conducted to define the near optimum allocation of cooling energy for these scenarios that meets the thermal design objectives. Additionally, sub-threshold leakage for the CPU is taken into account to enhance the model since temperature provides positive feedback. It is shown through modeling that additional performance enhancement is possible with judicious allocation of cooling energy for a given overall energy budget. It is argued in this paper that overall energy efficiency can be improved significantly through intelligent data driven energy allocation.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"33 1","pages":"568-573"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81533493","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.2014.6892332
Bharath Nagendran, S. Nagaraj, J. Fernandes, R. Eiland, D. Agonafer, V. Mulay
As a common practice in the data center industry, chassis fans are used to direct air flow independent from neighboring servers. In general, smaller fans are less efficient compared to geometrically similar larger fans. In this study, a novel approach is proposed whereby chassis enclosed fans are replaced with a smaller number of larger fans installed behind a stacked array of servers which share airflow. As a baseline study, a CPU dominated 1.5U Open Compute server with four 60mm fans installed within its chassis is characterized experimentally for its flow impedance, fan speed dependent flow rate, effect on die temperature and power consumption at various compute utilization levels. Larger fans with a square frame size of 80mm and 120mm are selected and individually characterized for their air moving capacity and power consumption. Primary emphasis is placed on the 80mm fan case, with discussion of the 120mm fans included. CFD is used to simulate a system of stacked servers serviced by larger fans to obtain its flow characteristics and operating points. The fan power consumption of the larger fans is determined experimentally at these operating points replicated in an air flow bench. Comparing with the base line experiments, replacing smaller fans with larger units results in a significant decrease in fan power consumption without conceding flow rate and static pressure requirements.
作为数据中心行业的一种常见做法，机箱风扇用于引导空气流动，而不依赖于相邻的服务器。一般来说，与几何形状相似的大型风扇相比，较小的风扇效率较低。在本研究中，提出了一种新颖的方法，即将机箱封闭的风扇替换为安装在堆叠服务器阵列后面的数量较少的较大风扇，从而共享气流。作为基线研究，以CPU为主的1.5U Open Compute服务器为例，在机箱内安装4个60mm风扇，实验表征了不同计算利用率下的流阻抗、风扇转速相关的流量、对芯片温度和功耗的影响。选择方形框架尺寸为80mm和120mm的大型风扇，并根据其空气移动能力和功耗进行单独表征。主要重点放在80mm风扇机箱上，包括对120mm风扇的讨论。利用CFD模拟了一个由大型风扇服务的堆叠服务器系统，以获得其流动特性和工作点。在空气流动实验台上复制这些工作点，实验确定了较大风扇的风扇功耗。与基线实验相比，在不降低流量和静压要求的情况下，用大风机代替小风机可以显著降低风机功耗。
{"title":"Improving cooling efficiency of servers by replacing smaller chassis enclosed fans with larger rack-mount fans","authors":"Bharath Nagendran, S. Nagaraj, J. Fernandes, R. Eiland, D. Agonafer, V. Mulay","doi":"10.1109/ITHERM.2014.6892332","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892332","url":null,"abstract":"As a common practice in the data center industry, chassis fans are used to direct air flow independent from neighboring servers. In general, smaller fans are less efficient compared to geometrically similar larger fans. In this study, a novel approach is proposed whereby chassis enclosed fans are replaced with a smaller number of larger fans installed behind a stacked array of servers which share airflow. As a baseline study, a CPU dominated 1.5U Open Compute server with four 60mm fans installed within its chassis is characterized experimentally for its flow impedance, fan speed dependent flow rate, effect on die temperature and power consumption at various compute utilization levels. Larger fans with a square frame size of 80mm and 120mm are selected and individually characterized for their air moving capacity and power consumption. Primary emphasis is placed on the 80mm fan case, with discussion of the 120mm fans included. CFD is used to simulate a system of stacked servers serviced by larger fans to obtain its flow characteristics and operating points. The fan power consumption of the larger fans is determined experimentally at these operating points replicated in an air flow bench. Comparing with the base line experiments, replacing smaller fans with larger units results in a significant decrease in fan power consumption without conceding flow rate and static pressure requirements.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"21 1","pages":"574-582"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82868650","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.2014.6892362
Yasin U. Makwana, Andrew R. Calder, S. Shrivastava
Data centers are mission-critical facilities and the nerve center of successful business operations. Surging demand for processing power, work load virtualization and consolidation is increasing data center heat loads, making the thermal management of data centers challenging. Containing the air in a data center is an important energy savings strategy towards data center optimization. Most of the modern, energy efficient, data centers deploy some kind of containment system. This paper discusses test data for a Cold Aisle Containment (CAC) system and compares it with a standard Hot Aisle/Cold Aisle (HA/CA) configuration. The HA/CA configuration is shown to support a heat load of 14.6kW/cabinet while the CAC system was tested up to 25.2 kW/cabinet. In addition, the test data demonstrated the cooling energy savings with the CAC system. Furthermore, we quantified the importance and effectiveness of sealing accessories (i.e. grommets for cable openings and blanking panels) when deployed in a CAC environment.
{"title":"Benefits of properly sealing a cold aisle containment system","authors":"Yasin U. Makwana, Andrew R. Calder, S. Shrivastava","doi":"10.1109/ITHERM.2014.6892362","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892362","url":null,"abstract":"Data centers are mission-critical facilities and the nerve center of successful business operations. Surging demand for processing power, work load virtualization and consolidation is increasing data center heat loads, making the thermal management of data centers challenging. Containing the air in a data center is an important energy savings strategy towards data center optimization. Most of the modern, energy efficient, data centers deploy some kind of containment system. This paper discusses test data for a Cold Aisle Containment (CAC) system and compares it with a standard Hot Aisle/Cold Aisle (HA/CA) configuration. The HA/CA configuration is shown to support a heat load of 14.6kW/cabinet while the CAC system was tested up to 25.2 kW/cabinet. In addition, the test data demonstrated the cooling energy savings with the CAC system. Furthermore, we quantified the importance and effectiveness of sealing accessories (i.e. grommets for cable openings and blanking panels) when deployed in a CAC environment.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"76 1","pages":"793-797"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82356560","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.2014.6892410
D. Squiller, E. Mengotti, P. McCluskey
The demand for power electronic systems to operate in harsh environmental conditions has increased over the past 20 years. These environments include those relating to deep oil-well drilling, automotive and aerospace applications. The miniaturization of the power module along with higher power densities have created elevated stress levels on ancillary subsystems, specifically the control circuitry. This study develops first-order methods and models to assess the solder interconnect reliability of critical components on the control circuitry in power electronic systems. Thermal and reliability simulations based upon Physics-of-Failure modeling techniques were conducted on a 2.2 kW variable-frequency drive to evaluate the susceptibility of component level failure mechanisms. CalcePWA, an interconnect reliability modeling software tool, was used as the primary vehicle to conduct these simulation models. A power cycling apparatus was constructed in order to calibrate the reliability models through accelerated testing of the drive.
{"title":"Assessing solder interconnect reliability of control boards in power electronic systems using Physics-of-Failure models","authors":"D. Squiller, E. Mengotti, P. McCluskey","doi":"10.1109/ITHERM.2014.6892410","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892410","url":null,"abstract":"The demand for power electronic systems to operate in harsh environmental conditions has increased over the past 20 years. These environments include those relating to deep oil-well drilling, automotive and aerospace applications. The miniaturization of the power module along with higher power densities have created elevated stress levels on ancillary subsystems, specifically the control circuitry. This study develops first-order methods and models to assess the solder interconnect reliability of critical components on the control circuitry in power electronic systems. Thermal and reliability simulations based upon Physics-of-Failure modeling techniques were conducted on a 2.2 kW variable-frequency drive to evaluate the susceptibility of component level failure mechanisms. CalcePWA, an interconnect reliability modeling software tool, was used as the primary vehicle to conduct these simulation models. A power cycling apparatus was constructed in order to calibrate the reliability models through accelerated testing of the drive.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"35 1","pages":"1154-1163"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75418126","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.2014.6892403
M. David, R. Schmidt
Data centers consume a significant amount of energy in the US and worldwide, much of which is consumed by the cooling infrastructure, particularly the chiller plant and computer room air conditioners and air handlers. To enable energy efficient data center designs, ASHRAE added two new IT environmental classes, A3 and A4, with associated allowable inlet air temperatures of 40C and 45C respectively. IT equipment that meet these new allowable environmental envelopes can operate in data centers with minimal refrigeration cooling and instead rely on ambient free cooling. In this paper we investigate the impact of allowing a data center to operate up to the A3 limit of 40C on total data center energy use for 3 different types of servers in a chiller-less data center located in a variety of locations. The study finds that though facility power reduces as the demand for cold air reduces, the increase in IT power consumption, due to fan speed-up, can offset these savings and in some cases result in an overall increase in data center power. Thus the most energy efficient operating point is dependant on the specific energy use profiles of the infrastructure and the IT equipment. The higher allowable temperature can also result in higher failure rates and an increased risk of equipment or service loss due to data center cooling failures. This paper also presents a study on the potential for chiller elimination and chiller use reduction across the US, Europe and in India by operating in the various ASHRAE envelopes. For wet, water side economized data centers, A2 and A3 equipment is sufficient to almost completely remove the need for chillers in many geographic locations.
{"title":"Impact of ASHRAE environmental classes on data centers","authors":"M. David, R. Schmidt","doi":"10.1109/ITHERM.2014.6892403","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892403","url":null,"abstract":"Data centers consume a significant amount of energy in the US and worldwide, much of which is consumed by the cooling infrastructure, particularly the chiller plant and computer room air conditioners and air handlers. To enable energy efficient data center designs, ASHRAE added two new IT environmental classes, A3 and A4, with associated allowable inlet air temperatures of 40C and 45C respectively. IT equipment that meet these new allowable environmental envelopes can operate in data centers with minimal refrigeration cooling and instead rely on ambient free cooling. In this paper we investigate the impact of allowing a data center to operate up to the A3 limit of 40C on total data center energy use for 3 different types of servers in a chiller-less data center located in a variety of locations. The study finds that though facility power reduces as the demand for cold air reduces, the increase in IT power consumption, due to fan speed-up, can offset these savings and in some cases result in an overall increase in data center power. Thus the most energy efficient operating point is dependant on the specific energy use profiles of the infrastructure and the IT equipment. The higher allowable temperature can also result in higher failure rates and an increased risk of equipment or service loss due to data center cooling failures. This paper also presents a study on the potential for chiller elimination and chiller use reduction across the US, Europe and in India by operating in the various ASHRAE envelopes. For wet, water side economized data centers, A2 and A3 equipment is sufficient to almost completely remove the need for chillers in many geographic locations.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"11 1","pages":"1092-1099"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75313844","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.2014.6892367
Van Gils, M. Speetjens, H. Zwart, H. Nijmeijer
Topic is feedback stabilisation of a nonlinear pool-boiling system in three spatial dimensions (3D). Regulation of its unstable (non-uniform) equilibria has great potential for application in micro-electronics cooling and thermal-management systems. Here, as a first step, stabilisation of such 3D equilibria is considered. A control law is designed that regulates the heat supply to the heater as a function of the Fourier-Chebyshev modes of its internal temperature distribution. This admits a controller that is tailored to the system dynamics, as these modes intimately relate to the physical eigenmodes. The internal temperature distribution is, similar to practical situations, estimated from a finite number of measurement positions on the heater surface by an observer. Performance of this output-based modal controller is demonstrated and analysed by simulations of the nonlinear closed-loop system. This provides first proof of principle of the proposed control strategy for the regulation of 3D boiling states.
{"title":"Modal control of unstable boiling states in three-dimensional nonlinear pool-boiling","authors":"Van Gils, M. Speetjens, H. Zwart, H. Nijmeijer","doi":"10.1109/ITHERM.2014.6892367","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892367","url":null,"abstract":"Topic is feedback stabilisation of a nonlinear pool-boiling system in three spatial dimensions (3D). Regulation of its unstable (non-uniform) equilibria has great potential for application in micro-electronics cooling and thermal-management systems. Here, as a first step, stabilisation of such 3D equilibria is considered. A control law is designed that regulates the heat supply to the heater as a function of the Fourier-Chebyshev modes of its internal temperature distribution. This admits a controller that is tailored to the system dynamics, as these modes intimately relate to the physical eigenmodes. The internal temperature distribution is, similar to practical situations, estimated from a finite number of measurement positions on the heater surface by an observer. Performance of this output-based modal controller is demonstrated and analysed by simulations of the nonlinear closed-loop system. This provides first proof of principle of the proposed control strategy for the regulation of 3D boiling states.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"255 1","pages":"833-839"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78986159","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.2014.6892314
J. Gess, S. Bhavnani, Bharath Ramakrishnan, R. Johnson, D. Harris, R. Knight, M. Hamilton, C. Ellis, J. Gess
The impact of increasing power consumption trends on a global economy with limited resources to sustain them cannot be understated. As worldwide communication requirements expand, data centers will need to be designed more efficiently to not only keep operation costs down for a business' bottom line, but also to be mindful of the world's power availability and resource supply. Therefore, the importance of designing data centers efficiently, but also compactly grows in step with society's power demands. To integrate into this new smarter data center, work has been completed on a small form factor, modular, high performance liquid immersion cooled server model with heat dissipations of over 700 Watts. These high power dissipations were achieved by the integration of enhanced surfaces affixed to the bare silicon die to promote increased boiling performance. The two surfaces tested were a sintered copper microporous heat sink and one that contained a dense array of microscale fins.
{"title":"Impact of surface enhancements upon boiling heat transfer in a liquid immersion cooled high performance small form factor server model","authors":"J. Gess, S. Bhavnani, Bharath Ramakrishnan, R. Johnson, D. Harris, R. Knight, M. Hamilton, C. Ellis, J. Gess","doi":"10.1109/ITHERM.2014.6892314","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892314","url":null,"abstract":"The impact of increasing power consumption trends on a global economy with limited resources to sustain them cannot be understated. As worldwide communication requirements expand, data centers will need to be designed more efficiently to not only keep operation costs down for a business' bottom line, but also to be mindful of the world's power availability and resource supply. Therefore, the importance of designing data centers efficiently, but also compactly grows in step with society's power demands. To integrate into this new smarter data center, work has been completed on a small form factor, modular, high performance liquid immersion cooled server model with heat dissipations of over 700 Watts. These high power dissipations were achieved by the integration of enhanced surfaces affixed to the bare silicon die to promote increased boiling performance. The two surfaces tested were a sintered copper microporous heat sink and one that contained a dense array of microscale fins.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"65 6 1","pages":"435-443"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87533758","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.2014.6892370
B. Wunderle, M. Springborn, D. May, C. Manier, M. Abo Ras, R. Mrossko, H. Oppermann, T. Xhonneux, T. Caroff, W. Maurer, R. Mitova
This paper deals with the system design, technology and test of a novel concept of integrating Silicon power dies along with thermo-electric coolers and a phase change heat buffer in order to thermally manage transients occurring during operation. The concept features double-sided cooling as well as new materials and joining technologies to integrate the dies such as transient liquid phase bonding/soldering and sintering. Coupled-field simulations are used to predict thermal performance and are verified by especially designed test stands to very good agreement.
{"title":"Double-sided cooling and transient thermo-electrical management of Silicon on DCB assemblies for power converter modules: Design, technology and test","authors":"B. Wunderle, M. Springborn, D. May, C. Manier, M. Abo Ras, R. Mrossko, H. Oppermann, T. Xhonneux, T. Caroff, W. Maurer, R. Mitova","doi":"10.1109/ITHERM.2014.6892370","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892370","url":null,"abstract":"This paper deals with the system design, technology and test of a novel concept of integrating Silicon power dies along with thermo-electric coolers and a phase change heat buffer in order to thermally manage transients occurring during operation. The concept features double-sided cooling as well as new materials and joining technologies to integrate the dies such as transient liquid phase bonding/soldering and sintering. Coupled-field simulations are used to predict thermal performance and are verified by especially designed test stands to very good agreement.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"8 1","pages":"851-861"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84701309","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.2014.6892336
M. Sabale, Kiran Vinerkar, S. Thakur, S. Tonapi
The trends towards miniaturization in the electronics industry coupled with advances in flip chip technology have increased the use of flip chip on board or direct chip attach technology in many products. This is especially true for products where re-work is not an option. Reliability issues were overcome by the use of underfill to couple the chip to the substrate and subsequently significant advances were made in underfill technology to give options like traditional capillary flow underfills to no-flow and wafer level underfill materials and processes. While significant research has been conducted and published in the area of flip chip on organic substrates as well as on underfill technology, there is still a lot that needs to be done in the area of flip chip on flexible substrates. There is significant potential for flip chip on flexible substrates as it is demonstrated in many applications like implantable medical devices, hard disk drives etc. As we move from rigid to flexible substrates the thickness reduces from the standard 62 mil - 31 mil range to 10 mil - 4 mil range. The change in thickness also changes the reliability issues and failure modes as compared to flip chip on rigid organic substrates. In this paper, we have investigated the effect of underfill geometry (height and width of fillet) on die cracking during thermal cycling. Package is subjected to the -55°C to 125°C accelerated thermal cycling. A 3 Dimensional Finite Element Analysis model is created and used to computationally evaluate the effect of various parameters and draw inferences on die cracking in flip chip on flexible substrates.
电子工业的小型化趋势加上倒装芯片技术的进步，在许多产品中增加了对板上倒装芯片或直接芯片连接技术的使用。对于不能返工的产品来说尤其如此。通过使用下填料将芯片耦合到基板上，克服了可靠性问题，随后在下填料技术方面取得了重大进展，可以选择传统的毛细管流下填料，也可以选择无流和晶圆级下填料材料和工艺。虽然在有机基板上的倒装芯片以及下填技术领域已经进行了大量的研究，但在柔性基板上的倒装芯片领域仍有很多工作要做。柔性基板上的倒装芯片具有巨大的潜力，因为它在许多应用中都得到了证明，如植入式医疗设备、硬盘驱动器等。当我们从刚性基材转移到柔性基材时，厚度从标准的62 mil - 31 mil范围减少到10 mil - 4 mil范围。与硬有机基板上的倒装芯片相比，厚度的变化也改变了可靠性问题和失效模式。在本文中，我们研究了下填料几何形状(圆角的高度和宽度)对热循环过程中模具开裂的影响。封装经受-55°C至125°C加速热循环。建立了三维有限元分析模型，对柔性基板倒装芯片中各参数对模具开裂的影响进行了计算和分析。
{"title":"Effect of underfill design parameters on die cracking in flip chip on flexible substrates","authors":"M. Sabale, Kiran Vinerkar, S. Thakur, S. Tonapi","doi":"10.1109/ITHERM.2014.6892336","DOIUrl":"https://doi.org/10.1109/ITHERM.2014.6892336","url":null,"abstract":"The trends towards miniaturization in the electronics industry coupled with advances in flip chip technology have increased the use of flip chip on board or direct chip attach technology in many products. This is especially true for products where re-work is not an option. Reliability issues were overcome by the use of underfill to couple the chip to the substrate and subsequently significant advances were made in underfill technology to give options like traditional capillary flow underfills to no-flow and wafer level underfill materials and processes. While significant research has been conducted and published in the area of flip chip on organic substrates as well as on underfill technology, there is still a lot that needs to be done in the area of flip chip on flexible substrates. There is significant potential for flip chip on flexible substrates as it is demonstrated in many applications like implantable medical devices, hard disk drives etc. As we move from rigid to flexible substrates the thickness reduces from the standard 62 mil - 31 mil range to 10 mil - 4 mil range. The change in thickness also changes the reliability issues and failure modes as compared to flip chip on rigid organic substrates. In this paper, we have investigated the effect of underfill geometry (height and width of fillet) on die cracking during thermal cycling. Package is subjected to the -55°C to 125°C accelerated thermal cycling. A 3 Dimensional Finite Element Analysis model is created and used to computationally evaluate the effect of various parameters and draw inferences on die cracking in flip chip on flexible substrates.","PeriodicalId":12453,"journal":{"name":"Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"17 1","pages":"605-608"},"PeriodicalIF":0.0,"publicationDate":"2014-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84984156","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：