无铅焊点界面化合物及Kirkendall空洞实验研究
|
摘要
由于Pb元素具有毒性,各国相应的法规禁止使用含铅焊料,因此无铅焊料的研究迫在眉睫。目前已经有上百种无铅焊料。Sn-3.5Ag系无铅焊料具有高的力学性能和耐热疲劳性,常用于高温设备中,是目前最有可能替代Sn-Pb钎料的合金。而在热老化过程中,焊点界面IMCs层的厚度增加将引起接头的热疲劳寿命、抗剪强度和断裂韧性会减小。同时接头电迁移失效问题也引起了广泛的关注。本文根据设计了Cu/钎料(Sn-3.5Ag、Sn-3.5Ag-1.0Zn)接头用于热老化实验,Cu/钎料/Cu(Sn-3.5Ag、Sn-3.5Ag-1.0Zn)用于电迁移实验。所得的试样经过冷镶嵌、打磨抛光,采用SEM分析了热老化和电迁移阶段接头反应界面微观组织形貌及演变,界面相成分采用能谱仪EDX分析。主要结论如下:
1.在热老化实验中,Sn-3.5Ag/Cu界面反应初生相为η-Cu6Sn5,在老化阶段,Cu6Sn5与Cu之间新生成一层较薄的ε-Cu3Sn层。化合物层的厚度随老化时间的延长而增加。而对于Sn-3.5Ag-1.0Zn/Cu界面初生相也为Cu6Sn5,热化过程中,ε-Cu3Sn并没有出现,取而代之的是Cu5Zn8,化合物层的生长有所被抑制。
2.在电迁移过程中,互连接头两端电压变化可分为四个阶段,即迅速上升期、稳定期、电压波动期和继续增大失效期。迅速上升期时间较短,几分钟电压就能够达到稳定期。稳定期期间,对应着微型空洞的形成和转移,为电迁移的孕育期,经过短暂的波动期后,电压迅速升高,最终导致电迁移失效。
3. Sn-3.5Ag和Sn-3.5Ag-1.0Zn焊料电迁移温度为常温,平均电流密度为1.0×103A/cm2和1.4×103A/cm2,远远低于普遍认为的电流门槛值1×104A/cm2,但是电迁移失效依然在负极的拐角处发生了。利用ANSYS模拟凸点中电流分布,发现了在阴阳极电子流入口附近电流密度达到了1.4×104A/cm2,而实验观察到的电迁移失效正好发生在该处,很好的说明了电流塞集引起了电迁移失效。
4.由于电迁移的影响,IMCs生长出现明显的极性效应,Sn-3.5Ag和Sn-3.5Ag-1.0Zn焊料凸点互连接头正极界面的IMC都是随着电迁移进行单调增长的;而负极界面的IMCs都是随电迁移进行先增大后减小的,并且Sn-3.5Ag焊料接头是在5天时候IMCs到达最大值,而Sn-3.5Ag-1.0Zn焊料接头是在10天的时候到达最大值,同时同等条件下Sn-3.5Ag-1.0Zn焊料接头的IMCs都比Sn-3.5Ag焊料接头的小,说明Zn元素的加入有助于抑制凸点互连接头IMCs在电流载荷作用下的生长。
5.热场和电场条件下研究了界面Kirkendall空洞的形成和演变过程,对于Sn-3.5 Ag/Cu界面,老化阶段,Cu/Cu3Sn界面的微空洞数量很少,而且增加不明显。然而,在1×103 A/cm2电流密度条件下,电流载荷会加速Cu/Cu3Sn界面Kirkendall空洞的形成,并且明显具有极性特征,即阳极Cu/Cu3Sn界面Kirkendall空洞的密度明显高于阴极。同时在Cu基板上镀一层Ni-P层可以起到抑制Kirkendall空洞的产生。而对于Sn-3.5 Ag-1.0Zn/Cu界面,在热老化和电迁移过程都没有产生Kirkendall空洞。
Due to the toxicity of Pb, the elimination of toxic lead (Pb) from electronic products is a global tendency actively driven by legislation. So, the development of a good lead-free solder which is environmentally friendly materials is a great challenge. There are about 100 kinds of lead-free solders from various researches and public. The eutectic Sn-3.5Ag was one of the most promising and extensively studied lead-free solder, for its excellent wettability, thermal and mechanical properties. During aging, the intermetallic compounds(IMCs) are not stable and continue to grow in the stage of solidification. The electromigration(EM) has attracted lots of attention. In this paper, a Cu/Solder structure was designed for aging experiment and Cu/Solder/Cu sandwich was designed for EM test, where solder is Sn-3.5Ag and Sn-3.5Ag-1.0Zn. The samples were through cold inlay, polishing and eroded, the microstructures of the interface were analyzed by using scanning electron microscope (SEM), chemical components were analyzed by using Electron Probe Micro Analysis (EPMA). Main conclusions are as follows.
1. In the aging experiment, for Sn-3.5Ag/Cu interface, the initial phase at the interface was scallop like Cu6Sn5. Meanwhile, a new layer, which was determined as Cu3Sn, was formed at Cu6Sn5/Cu interface after isothermal aging. For Sn-3.5Ag-1.0Zn/Cu interface, the initial phase was also Cu6Sn5. During the thermal aging, the formation of Cu3Sn was depressed and replaced by Cu5Zn8. The growth of IMCs at Sn-3.5Ag-1.0Zn/Cu interface was depressed.
2. In the EM experiment, the change of voltage of the solder bump joint can be divided into four periods, which are rapidly rising period, stable period, fluctuation period and failure period. The rapidly rising period is very short, about several minutes and then change into stable period, when the voids forms and transfers. And then, after a transient fluctuation period, the voltage rises rapidly and the failure happens.
3. Even when the current density is less than the minimum current density inducing EM evolution, the EM failure occurred in the incurrent ingress of cathode. Using ANSYS simulating the distribution of current, we found there was current crowding in the solder bump. So the EM failure happened.
4. Due to EM, the growth of IMCs had obvious polarity effects. For both Sn-3.5Ag solder and Sn-3.5Ag-1.0Zn solder, the IMCs in the anode interface, the thickness increased flatly. However, the IMCs in the cathode interface, the thickness increased first and the decreased. By comparing the thickness of the both solder, it was found that Zn could depress the growth of the IMCs under current.
5. The formation and evolution of Kirkendall voids were investigated under thermal aging and current stressing. At the 150℃aging process, only a small amount of micro-voids were formed at Cu/Cu3Sn interface. While current stressing of 1×103A/cm2 was found to accelerate the formation and growth of Kirkendall voids. Moreover, the formation of Kirkendall voids had a polarity effect under the current stressing, i.e., much higher density of Kirkendall voids at the anode side than that at the cathode side. We also found that the Ni-P UBM on the Cu and the addition of Zn could depress the formation and evolution of Kirkendall voids.
1.在热老化实验中,Sn-3.5Ag/Cu界面反应初生相为η-Cu6Sn5,在老化阶段,Cu6Sn5与Cu之间新生成一层较薄的ε-Cu3Sn层。化合物层的厚度随老化时间的延长而增加。而对于Sn-3.5Ag-1.0Zn/Cu界面初生相也为Cu6Sn5,热化过程中,ε-Cu3Sn并没有出现,取而代之的是Cu5Zn8,化合物层的生长有所被抑制。
2.在电迁移过程中,互连接头两端电压变化可分为四个阶段,即迅速上升期、稳定期、电压波动期和继续增大失效期。迅速上升期时间较短,几分钟电压就能够达到稳定期。稳定期期间,对应着微型空洞的形成和转移,为电迁移的孕育期,经过短暂的波动期后,电压迅速升高,最终导致电迁移失效。
3. Sn-3.5Ag和Sn-3.5Ag-1.0Zn焊料电迁移温度为常温,平均电流密度为1.0×103A/cm2和1.4×103A/cm2,远远低于普遍认为的电流门槛值1×104A/cm2,但是电迁移失效依然在负极的拐角处发生了。利用ANSYS模拟凸点中电流分布,发现了在阴阳极电子流入口附近电流密度达到了1.4×104A/cm2,而实验观察到的电迁移失效正好发生在该处,很好的说明了电流塞集引起了电迁移失效。
4.由于电迁移的影响,IMCs生长出现明显的极性效应,Sn-3.5Ag和Sn-3.5Ag-1.0Zn焊料凸点互连接头正极界面的IMC都是随着电迁移进行单调增长的;而负极界面的IMCs都是随电迁移进行先增大后减小的,并且Sn-3.5Ag焊料接头是在5天时候IMCs到达最大值,而Sn-3.5Ag-1.0Zn焊料接头是在10天的时候到达最大值,同时同等条件下Sn-3.5Ag-1.0Zn焊料接头的IMCs都比Sn-3.5Ag焊料接头的小,说明Zn元素的加入有助于抑制凸点互连接头IMCs在电流载荷作用下的生长。
5.热场和电场条件下研究了界面Kirkendall空洞的形成和演变过程,对于Sn-3.5 Ag/Cu界面,老化阶段,Cu/Cu3Sn界面的微空洞数量很少,而且增加不明显。然而,在1×103 A/cm2电流密度条件下,电流载荷会加速Cu/Cu3Sn界面Kirkendall空洞的形成,并且明显具有极性特征,即阳极Cu/Cu3Sn界面Kirkendall空洞的密度明显高于阴极。同时在Cu基板上镀一层Ni-P层可以起到抑制Kirkendall空洞的产生。而对于Sn-3.5 Ag-1.0Zn/Cu界面,在热老化和电迁移过程都没有产生Kirkendall空洞。
Due to the toxicity of Pb, the elimination of toxic lead (Pb) from electronic products is a global tendency actively driven by legislation. So, the development of a good lead-free solder which is environmentally friendly materials is a great challenge. There are about 100 kinds of lead-free solders from various researches and public. The eutectic Sn-3.5Ag was one of the most promising and extensively studied lead-free solder, for its excellent wettability, thermal and mechanical properties. During aging, the intermetallic compounds(IMCs) are not stable and continue to grow in the stage of solidification. The electromigration(EM) has attracted lots of attention. In this paper, a Cu/Solder structure was designed for aging experiment and Cu/Solder/Cu sandwich was designed for EM test, where solder is Sn-3.5Ag and Sn-3.5Ag-1.0Zn. The samples were through cold inlay, polishing and eroded, the microstructures of the interface were analyzed by using scanning electron microscope (SEM), chemical components were analyzed by using Electron Probe Micro Analysis (EPMA). Main conclusions are as follows.
1. In the aging experiment, for Sn-3.5Ag/Cu interface, the initial phase at the interface was scallop like Cu6Sn5. Meanwhile, a new layer, which was determined as Cu3Sn, was formed at Cu6Sn5/Cu interface after isothermal aging. For Sn-3.5Ag-1.0Zn/Cu interface, the initial phase was also Cu6Sn5. During the thermal aging, the formation of Cu3Sn was depressed and replaced by Cu5Zn8. The growth of IMCs at Sn-3.5Ag-1.0Zn/Cu interface was depressed.
2. In the EM experiment, the change of voltage of the solder bump joint can be divided into four periods, which are rapidly rising period, stable period, fluctuation period and failure period. The rapidly rising period is very short, about several minutes and then change into stable period, when the voids forms and transfers. And then, after a transient fluctuation period, the voltage rises rapidly and the failure happens.
3. Even when the current density is less than the minimum current density inducing EM evolution, the EM failure occurred in the incurrent ingress of cathode. Using ANSYS simulating the distribution of current, we found there was current crowding in the solder bump. So the EM failure happened.
4. Due to EM, the growth of IMCs had obvious polarity effects. For both Sn-3.5Ag solder and Sn-3.5Ag-1.0Zn solder, the IMCs in the anode interface, the thickness increased flatly. However, the IMCs in the cathode interface, the thickness increased first and the decreased. By comparing the thickness of the both solder, it was found that Zn could depress the growth of the IMCs under current.
5. The formation and evolution of Kirkendall voids were investigated under thermal aging and current stressing. At the 150℃aging process, only a small amount of micro-voids were formed at Cu/Cu3Sn interface. While current stressing of 1×103A/cm2 was found to accelerate the formation and growth of Kirkendall voids. Moreover, the formation of Kirkendall voids had a polarity effect under the current stressing, i.e., much higher density of Kirkendall voids at the anode side than that at the cathode side. We also found that the Ni-P UBM on the Cu and the addition of Zn could depress the formation and evolution of Kirkendall voids.
引文
[1] D.R. Frear, S.N. Burchett, H.S. Morgan, J.H. Lau. The Mechanics of Solder Alloy Interconnects,Van Nostrand Reinhold.1993:3-10.
[2] Armin Rahn. The Basics of Soldering. Wiley-Interscience, New York.1993:1-6.
[3] M.G. Fontana,N. D. Greene. Corrosion Engineering. McGraw-Hill BookCompany. 1978:12-15.
[4] Charles A. Harper.Handbook of Electronic Packaging. McGraw-Hill Company. 1969:10-20.
[5]黄明亮.电子封装无铅钎料研究[博士论文].大连:大连理工大学. 2002.
[6]贾红星,刘素芹,黄金亮等.电子组装用无铅钎料的研究进展[J].材料开发与应用,2003, 18 (5) :42-46.
[7]马鑫.无铅化电子组装技术. 2004年中国电子制造技术论坛. 2004:56-57.
[8] Zaccaria B. Filler materialsahe current situation and future trends with particular reference to 1ead-free soldering alloys[J].Welding Internationa1. 2001,15(7):545-551.
[9] K.N.Tu, K.Zeng. Tin-lead Solder Reaction in Flip Chip Technology[J]. Mater. Sci. Eng. 2001.34:1-58.
[10] T.Rao. Fundamentals of Microsystems Packaging [M]. New York: McGraw Hill. 2001,333-361.
[11] R.J.Li. Package Design and Materials Selection Optimization for Flip-chip Packaging. IEEE Transactions on Advanced Packaging 29 (3):525-532.
[12] Won Hwang, Jung-Goo Lee, Katsuaki Suganuma et al. Interfacial Micro-structure between Sn-3Ag-xBi Alloy and Cu Substrate with or without Electrolytic Ni plating. Journal of electronic materials[J]. Mater. Sci. Eng. 2003,32(2):52-62.
[13] Chang Tao Chih, Wang Moo Chin, Hon Min Hsiung. Growth and morphology of the intermetallic compounds formed at the Sn-9Zn-2.5Ag/Cu interface[J]. Journal of Alloys and Compounds. 2005(402):141-148.
[14] Ochoa. F, Williams. J. J, Chawla N. Effects of cooling rate on the microstructure and tensile behavior of a Sn3.5 wt.% Ag solder [J]. Journal of Electronic Materials.2003,32(12):1414-1420.
[15] P.L.Tu, Y.C.Cuan, J.L.Lai. Effect of intermetallic compounds on vibration fatigue of BGA solder joint [J]. IEEE Trans AdvPack.2001(24):197 - 205.
[16]马鑫,董本霞.无铅钎料发展现状.电子工艺技术.2002.3(23):110-118.
[17]王丽风,孙凤莲等.电子封装中的无铅Sn-3.8Ag-0.5Cu/Cu界面研究.哈尔滨理工大学学报.2005(8):401-410.
[18] Xin Ma, Fengjiang Wang etc. Development of Cu–Sn Intermetallic Compound at Pb-free Solder/Cu Joint Interface. Materials Letters 2003(57):3361-3365.
[19] Chang Tao Chih, Wang Moo Chin, Hon Min Hsiung. Growth and Morphology of The Intermetallic Compounds Formed at the Sn-Ag-xCu/Cu Interface [J]. Journal of Alloys and Compounds. 2005(402):141-148.
[20] K.N. Tu, T.Y. Lee, J.W. Jang, L. Li, D.R. Frear, K. Zeng, J.K.Kivilahti. Wetting Reaction vs. Solid-state Aging of Eutectic SnPb on Cu. Appl. Phys[J]. 2001(89): 4843-4849.
[21]何大鹏,于大全等.Cu含量对Sn-Cu钎料与Cu、Ni基板钎焊界面IMC的影响.中国有色金属学报.2006:410-416.
[22] Hsu S.C, Wang S.J , Liu C.Y. Effect of Cu Content on Interfacial Reactions between Sn (Cu) Alloys and Ni/Ti Thin-film Metallization[J].J Electron Mater,2003(32): 1214-1221.
[23] Wang S.J, Liu C.Y. Study of Interaction between Cu-Sn and Ni-Sn Interfacial Reactions by Ni/Sn3.5Ag2Cu Sandwich Structure [J] . Electron Mater, 2004(32): 1303-1309.
[24] Zeng K, Tu K.N. Six Cases of Reliability Study of Pb-free Solder Joints in Electronic Packaging Technology [J].Mater Sci Eng, 2002(38):55-105.
[25]何大鹏.合金元素对二元Sn基钎料钎焊界面工MC的影响[硕士学位论文].大连:大连理工大学.2005.
[26] P.L Tu, Y.C Chan. Growth Kinetics of Intermetallic Compounds in Chip Scale package Solder Joint[J]. Scripta mater. 2001(44):317–323.
[27] F. Gao, T. Takemoto, H. Nishikawa. Effects of Co and Ni addition on reactive diffusion between Sn–3.5Ag solder and Cu during soldering and annealing[J]. Materials Science and Engineering A. 2006(420):39–46.
[28]江清明,何小琦,杨春晖,周继承.集成电路可靠性电迁移评估技术,电子质量.2006(8):30-31.
[29]吴丰顺.倒装芯片互连凸点电迁移的研究进展.半导体技术.2004,29(6):10-15.
[30]吴懿平等.SnAgCu凸点互连的电迁移.半导体学报.2006,27(6):1136-1139.
[31]余春等.典型Sn基焊料凸点互连结构电迁移异同性.半导体学报.2007,28(4):620-623.
[32]张金松等.Cu-Ni/Solder/Ni-Cu互连结构的电迁移.半导体学报.2008,29(1):174-177.
[33]何洪文,徐广臣,郝虎,雷永平,郭福. SnAgCu无铅焊点的电迁移行为研究.电子元件与材料.2007,26(11):53-55.
[34] K.N. Tu. Recent advances on electromigration in very large scale integration of interconnects[J]. Appl. Phys.. 2003,94(9): 5451-5473.
[35] E.C. Yeth, W. J. Choi, K.N. Tu. Current crowding induced electromigration failure in flip chip technology[J]. Appl. Phys. Lett. 2002(80): 580-582.
[36] Glenn.A.Rinne. Electromigration in SnPb and Pb-free solder bumps[J]. Electronic Components and Technology Conference.2004: 974-980.
[37] H.B.Huntington, A.R.Grone. Journal of Physics Chemical Solids. 1961(76):20-26.
[38] Aris Christous. Electromigration and Electronic Device Degradation. 1St Edition. Canada: John Wiley&Sons INC..1994:1-46.
[39] K. L. Lee, C. K. Hu, K. N. Tu. J. Appl.Phys. 1995(78):4428-4435.
[40] T.Y.Lee,K.N.Tu. Electromigration of eutectic SnPb solder interconnects for flip chip technology[J]. J.Appl.Phys.. 2001,89(6):3189-3194.
[41] K.N.Tu. Recent advances on electromigration in very-large-scale-integration of interconnects[J]JOURNAL OF APPLIED PHYSICS. 2003,94(9):5451-5472.
[42] T.L.Shao, Y.H.Chen, S.H.Chiu, Chih.Chen. Electromigration failure mechanisms for SnAg3.5 solder bumps on Ti/Cr-Cu/Cu and Ni(P)/Au metallization pads[J]. Journal of Applied Physics. 2004(96): 4518-4525.
[43] J.S.Zhang,etal. Electromigration of Pb-free solder under a low level of current density[J].J.Alloys Compd. 2007(04):40-50.
[44] Kimihiro Yamanaka , Yutaka Tsukada , Katsuaki Suganuma. Solder electromigration in Cu/In/Cu flip chip joint system[J].Journal of Alloys and Compounds.2007(437):186-190.
[45] http://img2.zol.com.cn/product/3_450x337/268/ceYcUHkBCkkc.jpg.
[46] Yoon J W, Lee Y H, Kim D G, et al. Intermetallic compound layer growth at the interface between Sn-Cu-Ni solder and Cu substrate [J]. Journal of Alloys and Compounds, 2004, 381: 151-157.
[47]王烨,黄继华,张建纲,齐丽华. Sn-3.5Ag-0.5Cu/Cu界面的显微结构[J].中国有色金属学报, 2006, 16(3): 495-499.
[48]Zeng K J, Stierman R, Chiu T C, et al. Kirkendall void formation in eutectic SnPb solder joints on bare Cu and its effect on joint reliability [J]. Journal of Applied Physics, 2005, 97: 024508.
[49] Paul A, van Dal M J H, Kodentsov, et al. The Kirkendall effect in multiphase diffusion [J]. Acta Materialia, 2004, 52: 623-630.
[50] Liu C Y, Chen J T, Chuang Y C, et al. Electromigration-induced Kirkendall voids at the Cu/Cu3Sn interface in flip-chip Cu/Sn/Cu joints [J]. Applied Physics Letters, 2007, 90: 112114.
[51] Y.G. Lee, J.G. Duh.The Formation and Growth of Intermetallic Compound in The Solder Joint[J]. J. Mater. Sci.. 1998, 33(23): 5569-5572.
[52] Hsiao Y H,Chuang Y C,Liu C Y.Prevention of electromigration-induced Cu pad dissolution by using a high electromigration-resistance ternary Cu-Ni-Sn layer [J].Scripta Materialia,2006, 54: 661-664.
[53] Choi S, Lucas J P, Subramanian K.N, et al. Formation and growth of interfacial intermetallic layers in eutectic Sn-Ag solder and its composite solder joints [J]. Journal of Materials Science: Materials in Electronics, 2000, 11: 497-502.
[54]王丽凤,孙凤莲,梁英,姜志忠.无铅钎料/Cu焊盘接头的界面反应.Transactions of the China Weld Institution. 2005(6):153-158.
[55] Wang Fengjiang, Ma Xin, Qian Yiyu. Improvement of Microstructure and Interface Structure of Eutectic Sn-0.7Cu Solder with Small Amount of Zn Addition [J]. Scripta Materialia .2005(53) :699-702.
[56] Cheng S.C, Lin K.L. The Theremal Property of Lead-Free Sn-8.55Zn-1Ag-XAl Solder Alloys and their Wetting Interaction with Cu[J]. J. Electron. Mater. 2002(31): 940-945.
[57] Lee B.J, Hwang N.M, Lee H.M. Prediction of Interface Reaction Products between Cu and various Solder Alloys by Thermodynamic Calculations[J]. Acta Mater. 1997(45): 1867-1875.
[58] Chang Tao Chih, Wang Moo Chin, Hon Min Hsiung. Growth and Morphology of The Intermetallic Compounds Formed at the Sn-9Zn-2.5Ag/Cu Interface [J]. Journal ofAlloys and Compounds 2005(402):141-148.
[59] Chao Brook, Chae Seung Hyun, Zhang Xue Feng, Lu Kuan Hsun, Ding Min, Im Jay, Ho Paul S. Electro-migration Enhanced Intermetallic Growth and Void Formation in Pb-free Solder Joints[J]. Journal of Applied Physics. 2006(100):909-919.
[60] Chao Brook, Chae Seung Hyun, Zhang Xue Feng, et al. Electro-migration enhanced intermetallic growth and void formation in Pb-free solder joints [J]. Journal of Applied Physics, 2006: 084909-084919.
[2] Armin Rahn. The Basics of Soldering. Wiley-Interscience, New York.1993:1-6.
[3] M.G. Fontana,N. D. Greene. Corrosion Engineering. McGraw-Hill BookCompany. 1978:12-15.
[4] Charles A. Harper.Handbook of Electronic Packaging. McGraw-Hill Company. 1969:10-20.
[5]黄明亮.电子封装无铅钎料研究[博士论文].大连:大连理工大学. 2002.
[6]贾红星,刘素芹,黄金亮等.电子组装用无铅钎料的研究进展[J].材料开发与应用,2003, 18 (5) :42-46.
[7]马鑫.无铅化电子组装技术. 2004年中国电子制造技术论坛. 2004:56-57.
[8] Zaccaria B. Filler materialsahe current situation and future trends with particular reference to 1ead-free soldering alloys[J].Welding Internationa1. 2001,15(7):545-551.
[9] K.N.Tu, K.Zeng. Tin-lead Solder Reaction in Flip Chip Technology[J]. Mater. Sci. Eng. 2001.34:1-58.
[10] T.Rao. Fundamentals of Microsystems Packaging [M]. New York: McGraw Hill. 2001,333-361.
[11] R.J.Li. Package Design and Materials Selection Optimization for Flip-chip Packaging. IEEE Transactions on Advanced Packaging 29 (3):525-532.
[12] Won Hwang, Jung-Goo Lee, Katsuaki Suganuma et al. Interfacial Micro-structure between Sn-3Ag-xBi Alloy and Cu Substrate with or without Electrolytic Ni plating. Journal of electronic materials[J]. Mater. Sci. Eng. 2003,32(2):52-62.
[13] Chang Tao Chih, Wang Moo Chin, Hon Min Hsiung. Growth and morphology of the intermetallic compounds formed at the Sn-9Zn-2.5Ag/Cu interface[J]. Journal of Alloys and Compounds. 2005(402):141-148.
[14] Ochoa. F, Williams. J. J, Chawla N. Effects of cooling rate on the microstructure and tensile behavior of a Sn3.5 wt.% Ag solder [J]. Journal of Electronic Materials.2003,32(12):1414-1420.
[15] P.L.Tu, Y.C.Cuan, J.L.Lai. Effect of intermetallic compounds on vibration fatigue of BGA solder joint [J]. IEEE Trans AdvPack.2001(24):197 - 205.
[16]马鑫,董本霞.无铅钎料发展现状.电子工艺技术.2002.3(23):110-118.
[17]王丽风,孙凤莲等.电子封装中的无铅Sn-3.8Ag-0.5Cu/Cu界面研究.哈尔滨理工大学学报.2005(8):401-410.
[18] Xin Ma, Fengjiang Wang etc. Development of Cu–Sn Intermetallic Compound at Pb-free Solder/Cu Joint Interface. Materials Letters 2003(57):3361-3365.
[19] Chang Tao Chih, Wang Moo Chin, Hon Min Hsiung. Growth and Morphology of The Intermetallic Compounds Formed at the Sn-Ag-xCu/Cu Interface [J]. Journal of Alloys and Compounds. 2005(402):141-148.
[20] K.N. Tu, T.Y. Lee, J.W. Jang, L. Li, D.R. Frear, K. Zeng, J.K.Kivilahti. Wetting Reaction vs. Solid-state Aging of Eutectic SnPb on Cu. Appl. Phys[J]. 2001(89): 4843-4849.
[21]何大鹏,于大全等.Cu含量对Sn-Cu钎料与Cu、Ni基板钎焊界面IMC的影响.中国有色金属学报.2006:410-416.
[22] Hsu S.C, Wang S.J , Liu C.Y. Effect of Cu Content on Interfacial Reactions between Sn (Cu) Alloys and Ni/Ti Thin-film Metallization[J].J Electron Mater,2003(32): 1214-1221.
[23] Wang S.J, Liu C.Y. Study of Interaction between Cu-Sn and Ni-Sn Interfacial Reactions by Ni/Sn3.5Ag2Cu Sandwich Structure [J] . Electron Mater, 2004(32): 1303-1309.
[24] Zeng K, Tu K.N. Six Cases of Reliability Study of Pb-free Solder Joints in Electronic Packaging Technology [J].Mater Sci Eng, 2002(38):55-105.
[25]何大鹏.合金元素对二元Sn基钎料钎焊界面工MC的影响[硕士学位论文].大连:大连理工大学.2005.
[26] P.L Tu, Y.C Chan. Growth Kinetics of Intermetallic Compounds in Chip Scale package Solder Joint[J]. Scripta mater. 2001(44):317–323.
[27] F. Gao, T. Takemoto, H. Nishikawa. Effects of Co and Ni addition on reactive diffusion between Sn–3.5Ag solder and Cu during soldering and annealing[J]. Materials Science and Engineering A. 2006(420):39–46.
[28]江清明,何小琦,杨春晖,周继承.集成电路可靠性电迁移评估技术,电子质量.2006(8):30-31.
[29]吴丰顺.倒装芯片互连凸点电迁移的研究进展.半导体技术.2004,29(6):10-15.
[30]吴懿平等.SnAgCu凸点互连的电迁移.半导体学报.2006,27(6):1136-1139.
[31]余春等.典型Sn基焊料凸点互连结构电迁移异同性.半导体学报.2007,28(4):620-623.
[32]张金松等.Cu-Ni/Solder/Ni-Cu互连结构的电迁移.半导体学报.2008,29(1):174-177.
[33]何洪文,徐广臣,郝虎,雷永平,郭福. SnAgCu无铅焊点的电迁移行为研究.电子元件与材料.2007,26(11):53-55.
[34] K.N. Tu. Recent advances on electromigration in very large scale integration of interconnects[J]. Appl. Phys.. 2003,94(9): 5451-5473.
[35] E.C. Yeth, W. J. Choi, K.N. Tu. Current crowding induced electromigration failure in flip chip technology[J]. Appl. Phys. Lett. 2002(80): 580-582.
[36] Glenn.A.Rinne. Electromigration in SnPb and Pb-free solder bumps[J]. Electronic Components and Technology Conference.2004: 974-980.
[37] H.B.Huntington, A.R.Grone. Journal of Physics Chemical Solids. 1961(76):20-26.
[38] Aris Christous. Electromigration and Electronic Device Degradation. 1St Edition. Canada: John Wiley&Sons INC..1994:1-46.
[39] K. L. Lee, C. K. Hu, K. N. Tu. J. Appl.Phys. 1995(78):4428-4435.
[40] T.Y.Lee,K.N.Tu. Electromigration of eutectic SnPb solder interconnects for flip chip technology[J]. J.Appl.Phys.. 2001,89(6):3189-3194.
[41] K.N.Tu. Recent advances on electromigration in very-large-scale-integration of interconnects[J]JOURNAL OF APPLIED PHYSICS. 2003,94(9):5451-5472.
[42] T.L.Shao, Y.H.Chen, S.H.Chiu, Chih.Chen. Electromigration failure mechanisms for SnAg3.5 solder bumps on Ti/Cr-Cu/Cu and Ni(P)/Au metallization pads[J]. Journal of Applied Physics. 2004(96): 4518-4525.
[43] J.S.Zhang,etal. Electromigration of Pb-free solder under a low level of current density[J].J.Alloys Compd. 2007(04):40-50.
[44] Kimihiro Yamanaka , Yutaka Tsukada , Katsuaki Suganuma. Solder electromigration in Cu/In/Cu flip chip joint system[J].Journal of Alloys and Compounds.2007(437):186-190.
[45] http://img2.zol.com.cn/product/3_450x337/268/ceYcUHkBCkkc.jpg.
[46] Yoon J W, Lee Y H, Kim D G, et al. Intermetallic compound layer growth at the interface between Sn-Cu-Ni solder and Cu substrate [J]. Journal of Alloys and Compounds, 2004, 381: 151-157.
[47]王烨,黄继华,张建纲,齐丽华. Sn-3.5Ag-0.5Cu/Cu界面的显微结构[J].中国有色金属学报, 2006, 16(3): 495-499.
[48]Zeng K J, Stierman R, Chiu T C, et al. Kirkendall void formation in eutectic SnPb solder joints on bare Cu and its effect on joint reliability [J]. Journal of Applied Physics, 2005, 97: 024508.
[49] Paul A, van Dal M J H, Kodentsov, et al. The Kirkendall effect in multiphase diffusion [J]. Acta Materialia, 2004, 52: 623-630.
[50] Liu C Y, Chen J T, Chuang Y C, et al. Electromigration-induced Kirkendall voids at the Cu/Cu3Sn interface in flip-chip Cu/Sn/Cu joints [J]. Applied Physics Letters, 2007, 90: 112114.
[51] Y.G. Lee, J.G. Duh.The Formation and Growth of Intermetallic Compound in The Solder Joint[J]. J. Mater. Sci.. 1998, 33(23): 5569-5572.
[52] Hsiao Y H,Chuang Y C,Liu C Y.Prevention of electromigration-induced Cu pad dissolution by using a high electromigration-resistance ternary Cu-Ni-Sn layer [J].Scripta Materialia,2006, 54: 661-664.
[53] Choi S, Lucas J P, Subramanian K.N, et al. Formation and growth of interfacial intermetallic layers in eutectic Sn-Ag solder and its composite solder joints [J]. Journal of Materials Science: Materials in Electronics, 2000, 11: 497-502.
[54]王丽凤,孙凤莲,梁英,姜志忠.无铅钎料/Cu焊盘接头的界面反应.Transactions of the China Weld Institution. 2005(6):153-158.
[55] Wang Fengjiang, Ma Xin, Qian Yiyu. Improvement of Microstructure and Interface Structure of Eutectic Sn-0.7Cu Solder with Small Amount of Zn Addition [J]. Scripta Materialia .2005(53) :699-702.
[56] Cheng S.C, Lin K.L. The Theremal Property of Lead-Free Sn-8.55Zn-1Ag-XAl Solder Alloys and their Wetting Interaction with Cu[J]. J. Electron. Mater. 2002(31): 940-945.
[57] Lee B.J, Hwang N.M, Lee H.M. Prediction of Interface Reaction Products between Cu and various Solder Alloys by Thermodynamic Calculations[J]. Acta Mater. 1997(45): 1867-1875.
[58] Chang Tao Chih, Wang Moo Chin, Hon Min Hsiung. Growth and Morphology of The Intermetallic Compounds Formed at the Sn-9Zn-2.5Ag/Cu Interface [J]. Journal ofAlloys and Compounds 2005(402):141-148.
[59] Chao Brook, Chae Seung Hyun, Zhang Xue Feng, Lu Kuan Hsun, Ding Min, Im Jay, Ho Paul S. Electro-migration Enhanced Intermetallic Growth and Void Formation in Pb-free Solder Joints[J]. Journal of Applied Physics. 2006(100):909-919.
[60] Chao Brook, Chae Seung Hyun, Zhang Xue Feng, et al. Electro-migration enhanced intermetallic growth and void formation in Pb-free solder joints [J]. Journal of Applied Physics, 2006: 084909-084919.