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Liquid-Solid Electromigration Behavior of Cu/Sn-52In/Cu Micro-Interconnect |
Zhijie ZHANG1,Mingliang HUANG2() |
1 School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China 2 School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China |
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Cite this article:
Zhijie ZHANG,Mingliang HUANG. Liquid-Solid Electromigration Behavior of Cu/Sn-52In/Cu Micro-Interconnect. Acta Metall Sin, 2017, 53(5): 592-600.
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Abstract Electromigration (EM), which describes the mass transport due to the momentum exchange between conducting electrons and diffusing metal atoms under an applied electric field, has become a serious reliability issue in high-density packaging. With the increasing demands for miniaturization, liquid-solid (L-S) EM will pose a critical challenge to the reliability of solder interconnects. In this work, The interfacial reactions and diffusion behaviors of In, Sn and Cu atoms in Cu/Sn-52In/Cu interconnects during L-S EM under a current density of 2.0×104 A/cm2 at 120 and 180 ℃ have been in situ studied by using synchrotron radiation real-time imaging technology. During L-S EM, since there was no back-stress, the In atoms directionally migrated toward the anode due to the negative effective charge number (Z*) of In, which is different from the In atoms directionally migrated toward the cathode due to the back-stress induced by the preferential migration of the Sn atoms over the In atoms toward the anode during the solid-solid (S-S) EM. Furthermore, a modified expression for calculating the effective charge number Z* of liquid metals was proposed based on the enthalpy changes of melting process. The Z* of In atoms was calculated to be -2.30 and -1.14 at 120 and 180 ℃, respectively, which was consistent with the migration behavior of In atoms. The model provides a theoretical basis for determining the direction of the EM. The polarity effect, evidenced by the IMC layer at the anode growing continuously while that at the cathode was restrained, was resulted from the directional migration of In and Cu atoms toward the anode during L-S EM, which was more significant at high temperature. The consumption of cathode Cu during L-S EM followed a parabolic relationship with the EM time, and the consumption rate was magnitude higher at high temperature. The migrations of In atoms was discussed in terms of diffusion flux.
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Received: 10 November 2016
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Fund: Supported by National Natural Science Foundation of China (Nos.51475072 and 51671046) |
[1] | Chen L D, Huang M L, Zhou S M.Effect of electromigration on intermetallic compound formation in line-type Cu/Sn/Cu interconnect[J]. J. Alloys Compd., 2010, 504: 535 | [2] | Jung Y, Yu J.Electromigration induced kirkendall void growth in Sn-3.5Ag/Cu solder joints[J]. J. Appl. Phys., 2014, 115: 083708 | [3] | Huang M L, Zhou S M, Chen L D.Electromigration-induced interfacial reactions in Cu/Sn/electroless Ni-P solder interconnects[J]. J. Electron. Mater., 2012, 41: 730 | [4] | Chen C, Tong H M, Tu K N.Electromigration and thermomigration in Pb-free flip-chip solder joints[J]. Annu. Rev. Mater. Res., 2010, 40: 531 | [5] | Huang M L, Ye S, Zhao N.Current-induced interfacial reactions in Ni/Sn-3Ag-0.5Cu/Au/Pd(P)/Ni-P flip chip interconnect[J]. J. Mater. Res., 2011, 26: 3009 | [6] | Chen C, Liang S W.Electromigration issues in lead-free solder joints[J]. J. Mater. Sci.: Mater. Electron., 2007, 18: 259 | [7] | Yeh E C C, Choi W J, Tu K N. Current-crowding-induced electromigration failure in flip chip solder joints[J]. Appl. Phys. Lett., 2002, 80: 580 | [8] | Cahoon J R.A modified “Hole” theory for solute impurity diffusion in liquid metals[J]. Metall. Mater. Trans., 1997, 28A: 583 | [9] | Hu Y C, Lin Y H, Kao C R, et al.Electromigration failure in flip chip solder joints due to rapid dissolution of copper[J]. J. Mater. Res., 2003, 18: 2544 | [10] | Liao C N, Chung C P, Chen W T.Electromigration-induced Pb segregation in eutectic Sn-Pb molten solder[J]. J. Mater. Res., 2005, 20: 3425 | [11] | Gu X, Chan Y C.Electromigration in line-type Cu/Sn-Bi/Cu solder joints[J]. J. Electron. Mater., 2008, 37: 1721 | [12] | Huang M L, Zhou Q, Zhao N, et al.Reverse polarity effect and cross-solder interaction in Cu/Sn-9Zn/Ni interconnect during liquid-solid electromigration[J]. J. Mater. Sci., 2014, 49: 1755 | [13] | Huang M L, Zhou Q, Zhao N, et al.Abnormal diffusion behavior of Zn in Cu/Sn-9wt.% Zn/Cu interconnects during liquid-solid electromigration[J]. J. Electron. Mater., 2013, 42: 2975 | [14] | Huang M L, Zhang Z J, Zhao N, et al.A synchrotron radiation real-time in situ imaging study on the reverse polarity effect in Cu/Sn-9Zn/Cu interconnect during liquid-solid electromigration[J]. Scr. Mater., 2013, 68: 853 | [15] | Huang M L, Zhang Z J, Zhao N, et al.In situ study on reverse polarity effect in Cu/Sn-9Zn/Ni interconnect undergoing liquid-solid electromigration[J]. J. Alloys Compd., 2015, 619: 667 | [16] | Huang J R, Tsai C M, Lin Y W, et al.Pronounced electromigration of Cu in molten Sn-based solders[J]. J. Mater. Res., 2008, 23: 250 | [17] | Daghfal J P, Shang J K.Current-induced phase partitioning in eu |
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