表面沟槽对封装界面热阻的影响研究
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摘要
界面热阻对电子器件封装热管理有着重要的影响,它在封装总热阻中扮演着重要角色。广泛使用的粒子填充型热界面材料,具有高热导率、低成本、易操作等优点,可以有效降低封装散热中的界面热阻。但此类材料使用时易发生粒子堆积,生成厚的粘合层厚度(BLT),在热循环中产生空气孔洞和粘结裂纹等失效方式,反而增大了热界面材料的热阻RTIM。
表面沟槽能够显著改善粒子填充型热界面材料应用时遇到的上述问题。本文以表面沟槽为研究对象,主要研究工作与结论包括:
(1)回顾了热界面材料(TIM)的定义、作用、业界的研究进展,以及粒子填充型热界面材料所遇到的问题;然后在流体流动理论的基础上论证了表面沟槽能通过降低压力梯度、阻止粒子堆积来减小TIM的粘合层厚度。
(2)提出了一种能够评估表面沟槽影响热阻的实验方法,即通过测试有无表面沟槽的固—固接触面之间热界面材料的热阻值(RTIM)并进行对比。对比试验结果表明,表面沟槽能够显著降低RTIM,实验测试的结果中热阻降幅最高可达56.1%。
(3)对于使用较低热导率TIM的热界面,表面沟槽对RTIM的降幅更大,其原因是表面沟槽减小的粘合层厚度具有更大的热阻。
(4)对于同一热界面,界面压力的增大也能显著降低RTIM,且使用低热导率TIM的热界面,RTIM降低的趋势更显著。
(5)表面沟槽降低了粘合层厚度,去除了界面间部分的高热导率固体材料,增大了界面间换热面积。采用有限元法模拟计算上述变化对热阻的影响,结果显示界面热阻也能显著降低,模拟结果与前面的实验结果比较吻合。
本文提出的表面沟槽及其评估方法,对电子封装热管理设计有一定的参考价值。
Interfacial thermal resistance has a significant impact on thermal management of electronic device packaging, and it plays an important role in the total packaging thermal resistance. Particle-filled thermal interface materials which are widely used in electronic devices packaging,have the advantages of high thermal conductivity, low cost, easy to operate, etc., and they can effectively reduce the interfacial thermal resistance in thermal management of packaging. Drawbacks of these materials are the stacking of particles, formation a thick bondline thickness(BLT), and the susceptibility to air voiding and cohesive crack in the thermal cycling, on the contrary to increase the thermal resistance of thermal interface materials(RTIM).
Surface channels can significantly improve the above problems which particle-filled thermal interface materials have encountered in the applications. In this thesis, the surface channels are chosen as the research object and the main work are as follows:
(1) Firstly, the definition, function and research progress of thermal interface materials in industry have been reviewed, the problems which particle-filled thermal interface materials encountered in their applications have also been introduced; Secondly, the principle of surface channels reducing BLT through decreasing pressure gradient and preventing particle stacking has been demonstrated on the basis of fluid flow theory.
(2) An experimental method designed for evaluating the impact of surface channels on thermal resistance has been proposed, which by testing thermal resistance of the TIM(RTIM) in a solid-solid contact interface which may have surface channels and making comparison between them. The test results shows that surface channels can significantly reduce the thermal resistance of TIM(RTIM), in some cases of the test experiments the decreasing amplitude can be up to 56.1%.
(3) For the interface used the TIM which has relatively low thermal conductivity, surface channels can lead more decrease on RTIM. The reason is that the decreased BLT caused by surface channels have greater thermal resistance.
(4) Increasing the pressure on the thermal interface also can significantly reduce the RTIM. Furthermore, for the interface used the TIM which have lower thermal conductivity, the trend of decreasing of RTIM is more remarkable.
(5) Surface channels reduced the BLT, removed part of the material in the solid-solid interface which have relative high thermal conductivity, and increased the heat transfer area between the thermal interface. In this thesis, finite element method(FEM) has been used to simulate the impact of this changes on the interfacial thermal resistance. The results showed that surface channels can also significantly reduce the interfacial thermal resistance, the simulation results agree well with the experiments.
It is expected that the surface channels and its assessment methods proposed in this thesis have some reference value on the design of thermal management of electronic device packaging.
表面沟槽能够显著改善粒子填充型热界面材料应用时遇到的上述问题。本文以表面沟槽为研究对象,主要研究工作与结论包括:
(1)回顾了热界面材料(TIM)的定义、作用、业界的研究进展,以及粒子填充型热界面材料所遇到的问题;然后在流体流动理论的基础上论证了表面沟槽能通过降低压力梯度、阻止粒子堆积来减小TIM的粘合层厚度。
(2)提出了一种能够评估表面沟槽影响热阻的实验方法,即通过测试有无表面沟槽的固—固接触面之间热界面材料的热阻值(RTIM)并进行对比。对比试验结果表明,表面沟槽能够显著降低RTIM,实验测试的结果中热阻降幅最高可达56.1%。
(3)对于使用较低热导率TIM的热界面,表面沟槽对RTIM的降幅更大,其原因是表面沟槽减小的粘合层厚度具有更大的热阻。
(4)对于同一热界面,界面压力的增大也能显著降低RTIM,且使用低热导率TIM的热界面,RTIM降低的趋势更显著。
(5)表面沟槽降低了粘合层厚度,去除了界面间部分的高热导率固体材料,增大了界面间换热面积。采用有限元法模拟计算上述变化对热阻的影响,结果显示界面热阻也能显著降低,模拟结果与前面的实验结果比较吻合。
本文提出的表面沟槽及其评估方法,对电子封装热管理设计有一定的参考价值。
Interfacial thermal resistance has a significant impact on thermal management of electronic device packaging, and it plays an important role in the total packaging thermal resistance. Particle-filled thermal interface materials which are widely used in electronic devices packaging,have the advantages of high thermal conductivity, low cost, easy to operate, etc., and they can effectively reduce the interfacial thermal resistance in thermal management of packaging. Drawbacks of these materials are the stacking of particles, formation a thick bondline thickness(BLT), and the susceptibility to air voiding and cohesive crack in the thermal cycling, on the contrary to increase the thermal resistance of thermal interface materials(RTIM).
Surface channels can significantly improve the above problems which particle-filled thermal interface materials have encountered in the applications. In this thesis, the surface channels are chosen as the research object and the main work are as follows:
(1) Firstly, the definition, function and research progress of thermal interface materials in industry have been reviewed, the problems which particle-filled thermal interface materials encountered in their applications have also been introduced; Secondly, the principle of surface channels reducing BLT through decreasing pressure gradient and preventing particle stacking has been demonstrated on the basis of fluid flow theory.
(2) An experimental method designed for evaluating the impact of surface channels on thermal resistance has been proposed, which by testing thermal resistance of the TIM(RTIM) in a solid-solid contact interface which may have surface channels and making comparison between them. The test results shows that surface channels can significantly reduce the thermal resistance of TIM(RTIM), in some cases of the test experiments the decreasing amplitude can be up to 56.1%.
(3) For the interface used the TIM which has relatively low thermal conductivity, surface channels can lead more decrease on RTIM. The reason is that the decreased BLT caused by surface channels have greater thermal resistance.
(4) Increasing the pressure on the thermal interface also can significantly reduce the RTIM. Furthermore, for the interface used the TIM which have lower thermal conductivity, the trend of decreasing of RTIM is more remarkable.
(5) Surface channels reduced the BLT, removed part of the material in the solid-solid interface which have relative high thermal conductivity, and increased the heat transfer area between the thermal interface. In this thesis, finite element method(FEM) has been used to simulate the impact of this changes on the interfacial thermal resistance. The results showed that surface channels can also significantly reduce the interfacial thermal resistance, the simulation results agree well with the experiments.
It is expected that the surface channels and its assessment methods proposed in this thesis have some reference value on the design of thermal management of electronic device packaging.
引文
[1]田民波.电子封装工程. (第一版).北京:清华大学出版社, 2003. 2~3
[2]郑志荣.集成电路封装的发展与展望.微电子技术, 2002, 30(3): 1~5
[3] Rao R. Tummala. Fundamentals of Microsystems Packaging. (1 edition): McGraw- Hill Professional, 2001. 47~68
[4]夏扬,宋月清,崔舜等.热管理材料的研究进展.材料导报, 2008, 22(1): 4~7
[5]王长宏,朱冬生.电子封装热管理的热电冷却技术研究进展.电子元件与材料, 2008, 27(11): 4~7
[6] Nadarajah Narendran, Yimin Gu. Life of LED-Based White Light Sources. IEEE/OSA Journal of Display Technology, 2005, 1(1): 167~171
[7] Michael S. June, Kamal K. Sikka. Using Cap-integral Standoffs to Reduce Chip Hot -spot Temperatures in Electronic Packages. 2002 Inter Society Conference on Thermal Phenomena, 2002. 173~178
[8]黄大革,杨双根.高热流密度电子设备散热技术.流体机械, 2006, 34(9): 71~74
[9] Ravi S. Prasher, Jim Shipley, Suzana Prstic, etal. Thermal Resistance of Particle Laden Polymeric Thermal Interface Materials. 2003 ASME International Mechanical Engineering Congress, 2003. 1~9
[10] Ravis S. Prasher. Rheology Based Modeling and Design of Particle Laden Polymeric Thermal Interface Materials. IEEE Transactions on Components and Packaging Technologies, 2005, 28(2): 230~237
[11]林刚强. IC封装中的热设计探讨.电子工艺技术, 2008, 29(5): 278~281
[12] R. Linderman, T. Brunschwiler, B. Smith, etal. High-Performance Thermal Interface Technology Overview. Thermal Investigations of ICs and Systems (THERMINIC), 2007. 129~ 134
[13]周治国.激光光热法界面热阻测量系统研制: [硕士学位论文].武汉:武汉理工大学图书馆, 2006
[14]杨邦朝,陈文媛,曾理.热界面材料的特性及其应用.中国电子学会第十四届电子元件学术年会论文集, 2006. 111~121
[15] Chia-Pin Chiu, James G. Maveety, Quan A. Tran. Characterization of Solder Interfaces Using Laser Flash Metrology. Microelectronics Reliability, 2002, 42(1): 93~100
[16] K. Zhang, Y. Chai, M. M. F. Yuen, etal. Carbon Nanotube Thermal Interface Material for High-Brightness Light-Emitting-Diode Cooling. Nanotechnology, 2008, 19(21): 1~8
[17] Yang Chai, Kai Zhang, Min Zhang, etal. Carbon Nanotube/Copper Composites for Via Filling and Thermal Management. 2007 Electronic Components and Technology Conference, 2007. 1224~1229
[18] Jun Xu, Timnthy S. Fisher. Enhancement of Thermal Interface Materials With Carbon Nanotube Arrays. International Journal of Heat and Mass Transfer, 2006, 49(9~10): 1658~1666
[19]丁峰,谢维章.导热树脂基复合材料.复合材料学报, 1993, 10(3): 19~24
[20]井新利,李立匣.石墨-环氧树脂导热复合材料的研究.西安交通大学学报, 2000, 34(10): 106~110
[21]张晓辉,徐传骧.新型电力电子器件封装用导热胶粘剂的研究.电力电子技术, 1999, (5): 61~62
[22] J. P. Gwinn, R. L. Webb. Performance and Testing of Thermal Interface Materials. Microelectronics Journal, 2003, 34(3): 215~222
[23] R.S. Prasher. Thermal Interface Materials: Historical Perspective, Status and Future Directions. Proceedings of IEEE, 2006, 98(8): 1571~1586
[24] R. S. Prasher. Surface Chemistry and Characteristics Based Model for the Thermal Contact Resistance of Fluidic Interstitial Thermal Interface Materials. J. Heat Transfer, 2001, 123(5): 969~975
[25] A. Devpura, P. Phelan, R. Prasher. Percolation Theory Applied to the Analysis ofThermal Interface Materials in Flip-Chip Technology. Proc. IEEE Inter Society Conf. on Thermal Phenomena, 2000. 21~28
[26] R. J. Linderman, T. Brunschwiler, U. Kloter, etal. Hierarchical Nested Surface Channels for Reduced Particle Stacking and Low-Resistance Thermal Interfaces. Semiconductor Thermal Measurement and Management Symposium, 2007. 87~94
[27] I. Sushumna, R. K. Gupta, E. Ruckenstein. Stable, Highly Concentrated Suspensions for Electronic and Ceramic Materials Applications. J. Mater. Res., 1991, 6(5): 1082~1092
[28] Thomas Brunschwiler, Urs Kloter, Ryan J. Linderman, etal. Hierarchically Nested Channels for Fast Squeezing Interfaces With Reduced Thermal Resistance. IEEE Transactions on Components and Packaging Technologies, 2007, 30(2): 226~234
[29] R. Prasher, J. Shipley, S. Prstic, etal. Thermal Resistance of Particle Laden Polymeric Thermal Interface Materials. ASME J. Heat Transfer, 2003, 125(6): 1170~1177
[30] R. Mahajan, C-P. Chiu, R. Prasher. Thermal Interface Materials: A Brief Review of Design Characteristics and Materials. Electronics Cooling, 2004, 10(1): 10~18
[31] V. Singhal, T. Siegmund, S. V. Garimella. Optimization of Thermal Interface Materials for Electronics Cooling Applications. IEEE Trans. Comp. Packag. Technol., 2004, 27(2): 244~252
[32]徐佩弦.高聚物流变学及其应用. (第一版).北京:化学工业出版社, 2003, 51~52
[33]饶荣水.固体表面之间接触热阻的辨识研究.工业加热, 2003, 32(2): 16~19
[34]石零.氮化铝与无氧铜低温界面热阻的实验研究.真空与低温, 2004, 10(2): 82~84
[35]陈进,张广祥,王慧龄.一种新型界面热阻测量装置的设计.电子测试, 2007, (5): 51~53
[36]许国良,王晓墨,邬田华.工程传热学. (第一版).北京:中国电力出版社, 2005. 11~12
[37]王涓,孙岳明,黄庆安.单晶硅各向异性湿法腐蚀机理的研究进展.化工时刊,2004, 18(6): 1~4
[38]王涓. MEMS中单晶硅的湿法异向腐蚀特性的研究: (硕士学位论文).南京:东南大学图书馆, 2005
[39]安静.硅片在HF/HNO3/H2O体系中酸腐蚀的研究: (硕士学位论文).上海:上海交通大学图书馆, 2008
[40]赵兰萍,徐烈.固体界面间接触热阻的理论分析.中国空间科学技术, 2003, (4): 6~11
[41]沈军,马骏,刘伟强.一种接触热阻的数值计算方法.上海航天, 2009, 19(4): 33~36
[42]黄志华,王如竹,韩玉阁.一种接触热阻的预测方法.低温工程, 2000, (6): 40~46
[43]陈进,丁忠军,付秀玲等.基于MATLAB的氮化铝和铜界面热阻仿真.低温与特气, 2005, 23(4): 13~15
[2]郑志荣.集成电路封装的发展与展望.微电子技术, 2002, 30(3): 1~5
[3] Rao R. Tummala. Fundamentals of Microsystems Packaging. (1 edition): McGraw- Hill Professional, 2001. 47~68
[4]夏扬,宋月清,崔舜等.热管理材料的研究进展.材料导报, 2008, 22(1): 4~7
[5]王长宏,朱冬生.电子封装热管理的热电冷却技术研究进展.电子元件与材料, 2008, 27(11): 4~7
[6] Nadarajah Narendran, Yimin Gu. Life of LED-Based White Light Sources. IEEE/OSA Journal of Display Technology, 2005, 1(1): 167~171
[7] Michael S. June, Kamal K. Sikka. Using Cap-integral Standoffs to Reduce Chip Hot -spot Temperatures in Electronic Packages. 2002 Inter Society Conference on Thermal Phenomena, 2002. 173~178
[8]黄大革,杨双根.高热流密度电子设备散热技术.流体机械, 2006, 34(9): 71~74
[9] Ravi S. Prasher, Jim Shipley, Suzana Prstic, etal. Thermal Resistance of Particle Laden Polymeric Thermal Interface Materials. 2003 ASME International Mechanical Engineering Congress, 2003. 1~9
[10] Ravis S. Prasher. Rheology Based Modeling and Design of Particle Laden Polymeric Thermal Interface Materials. IEEE Transactions on Components and Packaging Technologies, 2005, 28(2): 230~237
[11]林刚强. IC封装中的热设计探讨.电子工艺技术, 2008, 29(5): 278~281
[12] R. Linderman, T. Brunschwiler, B. Smith, etal. High-Performance Thermal Interface Technology Overview. Thermal Investigations of ICs and Systems (THERMINIC), 2007. 129~ 134
[13]周治国.激光光热法界面热阻测量系统研制: [硕士学位论文].武汉:武汉理工大学图书馆, 2006
[14]杨邦朝,陈文媛,曾理.热界面材料的特性及其应用.中国电子学会第十四届电子元件学术年会论文集, 2006. 111~121
[15] Chia-Pin Chiu, James G. Maveety, Quan A. Tran. Characterization of Solder Interfaces Using Laser Flash Metrology. Microelectronics Reliability, 2002, 42(1): 93~100
[16] K. Zhang, Y. Chai, M. M. F. Yuen, etal. Carbon Nanotube Thermal Interface Material for High-Brightness Light-Emitting-Diode Cooling. Nanotechnology, 2008, 19(21): 1~8
[17] Yang Chai, Kai Zhang, Min Zhang, etal. Carbon Nanotube/Copper Composites for Via Filling and Thermal Management. 2007 Electronic Components and Technology Conference, 2007. 1224~1229
[18] Jun Xu, Timnthy S. Fisher. Enhancement of Thermal Interface Materials With Carbon Nanotube Arrays. International Journal of Heat and Mass Transfer, 2006, 49(9~10): 1658~1666
[19]丁峰,谢维章.导热树脂基复合材料.复合材料学报, 1993, 10(3): 19~24
[20]井新利,李立匣.石墨-环氧树脂导热复合材料的研究.西安交通大学学报, 2000, 34(10): 106~110
[21]张晓辉,徐传骧.新型电力电子器件封装用导热胶粘剂的研究.电力电子技术, 1999, (5): 61~62
[22] J. P. Gwinn, R. L. Webb. Performance and Testing of Thermal Interface Materials. Microelectronics Journal, 2003, 34(3): 215~222
[23] R.S. Prasher. Thermal Interface Materials: Historical Perspective, Status and Future Directions. Proceedings of IEEE, 2006, 98(8): 1571~1586
[24] R. S. Prasher. Surface Chemistry and Characteristics Based Model for the Thermal Contact Resistance of Fluidic Interstitial Thermal Interface Materials. J. Heat Transfer, 2001, 123(5): 969~975
[25] A. Devpura, P. Phelan, R. Prasher. Percolation Theory Applied to the Analysis ofThermal Interface Materials in Flip-Chip Technology. Proc. IEEE Inter Society Conf. on Thermal Phenomena, 2000. 21~28
[26] R. J. Linderman, T. Brunschwiler, U. Kloter, etal. Hierarchical Nested Surface Channels for Reduced Particle Stacking and Low-Resistance Thermal Interfaces. Semiconductor Thermal Measurement and Management Symposium, 2007. 87~94
[27] I. Sushumna, R. K. Gupta, E. Ruckenstein. Stable, Highly Concentrated Suspensions for Electronic and Ceramic Materials Applications. J. Mater. Res., 1991, 6(5): 1082~1092
[28] Thomas Brunschwiler, Urs Kloter, Ryan J. Linderman, etal. Hierarchically Nested Channels for Fast Squeezing Interfaces With Reduced Thermal Resistance. IEEE Transactions on Components and Packaging Technologies, 2007, 30(2): 226~234
[29] R. Prasher, J. Shipley, S. Prstic, etal. Thermal Resistance of Particle Laden Polymeric Thermal Interface Materials. ASME J. Heat Transfer, 2003, 125(6): 1170~1177
[30] R. Mahajan, C-P. Chiu, R. Prasher. Thermal Interface Materials: A Brief Review of Design Characteristics and Materials. Electronics Cooling, 2004, 10(1): 10~18
[31] V. Singhal, T. Siegmund, S. V. Garimella. Optimization of Thermal Interface Materials for Electronics Cooling Applications. IEEE Trans. Comp. Packag. Technol., 2004, 27(2): 244~252
[32]徐佩弦.高聚物流变学及其应用. (第一版).北京:化学工业出版社, 2003, 51~52
[33]饶荣水.固体表面之间接触热阻的辨识研究.工业加热, 2003, 32(2): 16~19
[34]石零.氮化铝与无氧铜低温界面热阻的实验研究.真空与低温, 2004, 10(2): 82~84
[35]陈进,张广祥,王慧龄.一种新型界面热阻测量装置的设计.电子测试, 2007, (5): 51~53
[36]许国良,王晓墨,邬田华.工程传热学. (第一版).北京:中国电力出版社, 2005. 11~12
[37]王涓,孙岳明,黄庆安.单晶硅各向异性湿法腐蚀机理的研究进展.化工时刊,2004, 18(6): 1~4
[38]王涓. MEMS中单晶硅的湿法异向腐蚀特性的研究: (硕士学位论文).南京:东南大学图书馆, 2005
[39]安静.硅片在HF/HNO3/H2O体系中酸腐蚀的研究: (硕士学位论文).上海:上海交通大学图书馆, 2008
[40]赵兰萍,徐烈.固体界面间接触热阻的理论分析.中国空间科学技术, 2003, (4): 6~11
[41]沈军,马骏,刘伟强.一种接触热阻的数值计算方法.上海航天, 2009, 19(4): 33~36
[42]黄志华,王如竹,韩玉阁.一种接触热阻的预测方法.低温工程, 2000, (6): 40~46
[43]陈进,丁忠军,付秀玲等.基于MATLAB的氮化铝和铜界面热阻仿真.低温与特气, 2005, 23(4): 13~15