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Acta Metall Sin  2015, Vol. 51 Issue (7): 873-882    DOI: 10.11900/0412.1961.2014.00525
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PHASE-FIELD CRYSTAL SIMULATION ON EVOLU- TION AND GROWTH KINETICS OF KIRKENDALL VOIDS IN INTERFACE AND INTERMETALLIC COMPOUND LAYER IN Sn/Cu SOLDERING SYSTEM
Wenjing MA,Changbo KE,Minbo ZHOU,Shuibao LIANG,Xinping ZHANG()
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640
Cite this article: 

Wenjing MA,Changbo KE,Minbo ZHOU,Shuibao LIANG,Xinping ZHANG. PHASE-FIELD CRYSTAL SIMULATION ON EVOLU- TION AND GROWTH KINETICS OF KIRKENDALL VOIDS IN INTERFACE AND INTERMETALLIC COMPOUND LAYER IN Sn/Cu SOLDERING SYSTEM. Acta Metall Sin, 2015, 51(7): 873-882.

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Abstract  

With the development of electronic products towards further miniaturization, multifunction and high-reliability, the packaging density has been increasing and the dimension of solder joints has been scaling down. In electronic packaging, during the soldering process of Sn/Cu system, an intermetallic compound (IMC) layer is formed at the interface between the molten solder and pad (substrate), the interfacial microstructure plays an important role in the reliability of solder interconnects. Generally, during the reflow soldering and subsequent aging process, a large number of Kirkendall voids may form at the Cu/Cu3Sn interface and in the Cu3Sn layer. The existence of Kirkendall voids may increase the potential for brittle interfacial fracture of solder interconnects and reduce the thermal conductivity. Thus, characterization of formation and growth of Kirkendall voids is very important for the evaluation of performance and reliability of solder interconnects. In this work, the formation and growth of Kirkendall voids at the Cu/Cu3Sn interface and in the Cu3Sn layer of Sn/Cu solder system have been investigated by means of phase field crystal modeling. The growth mechanism of Kirkendall voids was analyzed. The effects of thickness of Cu3Sn layer and impurity particles in the Cu3Sn layer on the growth of Kirkendall voids were discussed. Phase field simulation results show that the growth of Kirkendall voids exhibits four stages during the thermal aging, including the formation of atomic mismatch areas at the Cu/Cu3Sn interface, the rapid growth of the atomic mismatch areas leading to the formation of Kirkendall voids, the growth of Kirkendall voids and the subsequent coalescence of Kirkendall voids. Kirkendall voids nucleate preferentially at the Cu/Cu3Sn interface and their sizes increase with the aging time, and the coalescence of the voids can be observed obviously in the later stage of thermal aging. It has also been shown that the increase of the Cu3Sn layer thickness and the amount of impurity particles lead to an increase in both number and size of Kirkendall voids, as well as an increased growth exponent; and the number of Kirkendall voids increases initially and then decreases with the aging time.

Key words:  Kirkendall voids      intermetallic compound      growth kinetics      morphological evolution      phase-field crystal method     
Fund: Supported by National Natural Science Foundation of China (Nos.51275178 and 51205135) and Research Fund for the Doctoral Program of Higher Education of China (Nos.20110172110003 and 20130172120055)

URL: 

https://www.ams.org.cn/EN/10.11900/0412.1961.2014.00525     OR     https://www.ams.org.cn/EN/Y2015/V51/I7/873

  
Symbol Value Symbol Value
B 0 l 0.7 t 1 0.6
B 2 l -1.8 v 1.0
B x 1 K 4.0
n ? l -0.2571 w 1.0
ψ C u 0.2 u 4.0
ψ S n -0.2 n ? s -0.1503
Table 1  Material parameters used in the simulation of Sn/Cu soldering system [22]
Fig.2  Simulated morphologies of Kirkendall voids at the Cu/Cu3Sn interface and in the Cu3Sn layer at different time steps of t=0.1×105 (a), 3×105 (b), 5×105 (c), 7×105 (d) and the experimental observation of Kirkendall voids [3] in the Sn-3.0Ag-0.5Cu/Cu joint aged at 217 ℃ for 120 min (e) and 240 min (f)
Fig.3  Simulated morphologies of Kirkendall voids at the Cu/Cu3Sn interface and in the Cu3Sn layer at mobilities of MCu=1 and MSn=0.05 (a), 0.01 (b) and 0.005 (c)
Fig.4  Simulated morphologies of Kirkendall voids at the Cu/Cu3Sn interface with thickness ratios of Cu3Sn layer to Cu layer being 1∶1 (a1~a3), 9∶10 (b1~b3) and 4∶5 (c1~c3) at t=0.6×105 (a1, b1, c1), 1×105 (a2, b2, c2) and 7×105 (a3, b3, c3) (Insets show the corresponding enlarged views)
Fig.5  Time dependences of Kirkendall void number at the Cu/Cu3Sn interface with different Cu3Sn layer thicknesses
Fig.6  Time dependences of size of Kirkendall void at the Cu/Cu3Sn interface with different Cu3Sn layer thicknesses
Thickness ratio Kt nY RY2
Cu3Sn∶Cu=1∶1 1.679 1.126 0.983
Cu3Sn∶Cu=9∶10 2.689 0.535 0.980
Cu3Sn∶Cu=4∶5 6.152 0.312 0.994
Table 2  Exponential fitting results of time dependence of size of Kirkendall void at the Cu/Cu3Sn interface with different Cu3Sn layer thicknesses
  
Fig.8  Simulated morphologies of Kirkendall voids at the Cu/Cu3Sn interfaces with impurity concentrations of 12.98% (a1~a3), 22.26% (b1~b3) and 35.56% (c1~c3) at t=0.6×105 (a1, b1, c1), 1×105 (a2, b2, c2) and 7×105 (a3, b3, c3) (Insets show the corresponding enlarge views)
Fig.9  Time dependences of Kirkendall void number at the Cu/Cu3Sn interface with different impurity concentrations
Fig.10  Time dependences of Kirkendall void size at the Cu/Cu3Sn interface with different impurity concentrations
Impurity concentration Kt nY RY2
12.98% 0.0270 0.385 0.989
22.26% 0.2050 0.556 0.990
35.56% 0.5362 0.899 0.992
Table 3  Exponential fitting results of time dependence of Kirkendall void size at the Cu/Cu3Sn interface with different impurity concentrations
[1] Zeng K, Tu K N. Mater Sci Eng, 2002; R38: 55
[2] Ke C B, Zhou M B, Zhang X P. Acta Metall Sin, 2014; 50: 294 (柯常波, 周敏波, 张新平. 金属学报, 2014; 50: 294)
[3] Zhou M B, Ma X, Zhang X P. Acta Metall Sin, 2013; 49: 341 (周敏波, 马 骁, 张新平. 金属学报, 2013: 49: 341)
[4] Frear D R. JOM, 1996; 48: 49
[5] Shang J K, Yao D. J Electron Packag, 1996; 118: 170
[6] Abtew M, Selvaduray G. Mater Sci Eng, 2000; R27: 95
[7] Liang S B,Ke C B,Ma W J,Zhou M B,Zhang X P. In: Bi K Y ed., Proceedings of the 15th International Conference on Electronic Packaging Technology, Piscataway, NJ: IEEE Press, 2014: 641
[8] Besser P R, Madden M C, Flinn P A. J Appl Phys, 1992; 72: 3792
[9] Ahat S, Sheng M, Luo L. J Electron Mater, 2001; 30: 1317
[10] Lin X Q, Luo L. J Electron Mater, 2008; 37: 307
[11] Zeng K J, Stierman R, Chiu T C, Edwards D. J Appl Phys, 2005; 97: 024508-1
[12] Wang Y W, Lin Y W, Kao C R. J Alloys Compd, 2010; 493: 233
[13] Liu Y, Wang J, Yin L, Kondos P, Parks C, Borgesen P, Henderson D W, Cotts E J, Dimitrov N. J Appl Electrochem, 2008; 38: 1695
[14] Wafula F, Liu Y, Yin L, Bliznakov S, Borgesen P. J Electrochem Soc, 2010; 157: 111
[15] Wafula F, Liu Y, Yin L, Borgesen P. J Appl Electrochem, 2011; 41: 469
[16] Yin L, Borgesen P. J Mater Res, 2011; 26: 455
[17] Clark S J, Segall M D, Pickard C J, Hasnip P J, Probert M I J, Refson K, Payne M C. Z Kristallogr, 2005; 220: 567
[18] Fischer T H, Almlof J. J Phys Chem, 1992; 96: 9768
[19] Perdew J P, Burke K, Ernzerhof M. Phys Rev Lett, 1996; 77: 3865
[20] Vanderbilt D. Phys Rev, 1990; 41B: 7892
[21] Elder K R, Provatas N, Berry J, Stefanovic P, Grant M. Phys Rev, 2007; 75B: 064107-1
[22] Elder K R, Huang Z F, Provatas N. Phys Rev, 2010; 81E: 011602-1
[23] Elder K R, Thornton K, Hoyt J J. Philos Mag, 2011; 91: 151
[24] Berry J, Elder K R, Grant M. Phys Rev, 2008; 77B: 224114
[25] Mellenthin J, Karma A, Plapp M. Phys Rev, 2008; 78B: 184110
[26] Liu C Y, Ke L, Chuang Y C, Wang S J. J Appl Phys, 2006; 100: 083702
[27] Lee C H, Park C O. Jpn J Appl Phys, 2003; 42: 4484
[28] Kim J Y, Yu J. Appl Phys Lett, 2008; 92: 092109-1
[29] Weinberg K, B?hme T, Müller W H. Comput Mater Sci, 2009; 45: 827
[30] Yu J, Kim J Y. Acta Mater, 2008; 56: 5514
[31] Kim B J,Lim G T,Kim J,Lee K,Park Y B,Joo Y C. In: Wipiejewski T ed., Proceedings of the 58th Electronic Components and Technology Conference, Piscataway, NJ: IEEE Press, 2008: 336
[32] Christian J W. The Theory of Transformations in Metals and Alloys. London: Pergamon Press Oxford, 1965: 471
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