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Acta Metall Sin  2017, Vol. 53 Issue (2): 227-232    DOI: 10.11900/0412.1961.2016.00232
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Microstructures and Mechanical Properties of Cu/Sn/Cu Structure Ultrasonic-TLP Joint
Jihou LIU1,2,Hongyun ZHAO1,2,Zhuolin LI2(),Xiaoguo SONG1,2,Hongjie DONG1,2,Yixuan ZHAO1,2,Jicai FENG1,2
1 State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China2 Shandong Provincial Key Lab of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
2 Shandong Provincial Key Lab of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
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The energy density of chip is becoming increasingly higher with the power electronic devices developing toward miniaturization, high power and integration, which will lead a higher operating temperature. However, the traditional Sn-based soldering process fails to meet the elevated temperature. Transient liquid phase (TLP) soldering, which can form high-melting-point joints at relatively low temperatures, has been proven to be a promising bonding method for solving this technological challenge. Nevertheless, a common drawback for TLP soldering is that it will consume a very long time for the complete formation of intermetallic joints, up to tens of minutes, which will lead extra thermal stress and seriously negative effects on the reliability of packaging systems. Recently, this technological puzzle has been proven to be solved by a novel ultrasonic-assisted TLP soldering process, in which the ultrarapid formation of complete intermetallic joints was achieved due to the accelerated diffusion of Cu from the substrates into the molten Sn interlayer under the complex sonochemical effects of acoustic field on the interfacial reaction. In this study, the microstructure and mechanical properties of complete Cu-Sn intermetallic joints ultrarapidly formed by ultrasonic-assisted TLP soldering process were investigated. The sandwich Cu/Sn/Cu system was placed on the heating platform, and then the ultrasonic vibrations and the bonding force were applied on it. The horizontal ultrasonic frequency, pressure, power, bonding temperature and time were fixed as 20 kHz, 0.5 MPa, 300 W, 250 ℃ and 5 s. In summary, the complete intermetallic joints composed of Cu6Sn5 interlayer with a thickness about 15 μm and Cu3Sn boundary layers with a thickness about 1 μm were ultrarapidly formed by ultrasonic-assisted TLP soldering process. The formed Cu6Sn5 grains were remarkably refined to be with an average grain size less than 5 μm. Compared with the intermatllic joints formed by traditional TLP soldering process, the resulted intermetallic joints performed more uniform mechanical properties with elastic modulus and hardness of about 123 GPa and 6.0 GPa respectively, as well as a higher reliability with a shear strength of 60 MPa.

Key words:  transient      liquid      phase      soldering,      ultrasonic,      intermetallics,      nanoindentation,      shear      strength     
Received:  14 June 2016     
Fund: Supported by Natural Science Foundation of Shandong Province (No.ZR2016EEQ12)

Cite this article: 

Jihou LIU,Hongyun ZHAO,Zhuolin LI,Xiaoguo SONG,Hongjie DONG,Yixuan ZHAO,Jicai FENG. Microstructures and Mechanical Properties of Cu/Sn/Cu Structure Ultrasonic-TLP Joint. Acta Metall Sin, 2017, 53(2): 227-232.

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Fig.1  Schematic of the ultrasonic-assisted transient liquid phase (TLP) soldering process of Cu/Sn/Cu system (a) and the profile of soldering temperature (b)
Fig.2  Cross-sectional SEM image (a), EDS elemental distribution maps of Cu (b) and Sn (c) in the ultrasonic-assisted TLP joint
Fig.3  Cross-sectional images of the ultrasonic-assisted TLP joint
(a) grain mapping
(b) phase distribution
(c) pole figures of Cu6Sn5 (The plane of substrate was defined as the RD-ND plane, and the direction perpendicular to the substrate was defined as the TD)
(d) statistical graphs of Cu6Sn5 grain size
Fig.4  Naoidentation test points (a), load-displacement curve (b), AFM image of impression (c) and height-distance curve (d)
Impression Elastic modulus Hardness
1 123.03 5.97
2 123.02 5.99
3 123.04 5.98
4 123.03 6.01
5 123.04 5.99
Table 1  Elastic modulus and hardness of Cu6Sn5 intermetallics in different impressions in Fig.4a (GPa)
Fig.5  Fracture SEM image (a) and corresponding XRD spectrum (b) of ultrasonic-assisted TLP joint
[1] Neudeck P G, Okojie R S, Chen L Y.High-temperature electronics——A role for wide bandgap semiconductors?[J]. Proc. IEEE, 2002, 90: 1065
[2] Yoon S W, Glover M D, Shiozaki K.Nickel-tin transient liquid phase bonding toward high-temperature operational power electronics in electrified vehicles[J]. IEEE Trans. Power Electron., 2013, 28: 2448
[3] Li J F, Agyakwa P A, Johnson C M.Kinetics of Ag3Sn growth in Ag-Sn-Ag system during transient liquid phase soldering process[J]. Acta Mater., 2010, 58: 3429
[4] Bosco N S, Zok F W.Critical interlayer thickness for transient liquid phase bonding in the Cu-Sn system[J]. Acta Mater., 2004, 52: 2965
[5] Park M S, Gibbons S L, Arróyave R.Phase-field simulations of intermetallic compound growth in Cu/Sn/Cu sandwich structure under transient liquid phase bonding conditions[J]. Acta Mater., 2012, 60: 6278
[6] Park M S, Arróyave R.Early stages of intermetallic compound formation and growth during lead-free soldering[J]. Acta Mater., 2010, 58: 4900
[7] Schaefer M, Fournelle R A, Liang J.Theory for intermetallic phase growth between Cu and liquid Sn-Pb solder based on grain boundary diffusion control[J]. J. Electron. Mater., 1998, 27: 1167
[8] Prakash K H, Sritharan T.Interface reaction between copper and molten tin-lead solders[J]. Acta Mater., 2001, 49: 2481
[9] Zhou M B, Ma X, Zhang X P.The interfacial reaction and intermetallic compound growth behavior of BGA structure Sn-3.0Ag-0.5Cu/Cu solder joint at low reflow temperatures[J]. Acta Metall. Sin., 2013, 49: 341
[9] (周敏波, 马骁, 张新平. BGA结构Sn-3.0Ag-0.5Cu/Cu焊点低温回流时界面反应和IMC生长行为[J]. 金属学报, 2013, 49: 341)
[10] Hang C J, Tian Y H, Zhao X, et al.Research on microstructure of Pb-free BGA solder joint assembled with Sn-Pb solder during isothermal aging[J]. Acta Metall. Sin., 2013, 49: 831
[10] (杭春进, 田艳红, 赵鑫等. 混装BGA器件高温老化实验焊点微观组织研究[J]. 金属学报, 2013, 49: 831)
[11] Liu J H, Zhao H Y, Li Z L, et al.Study on the microstructure and mechanical properties of Cu-Sn intermetallic joints rapidly formed by ultrasonic-assisted transient liquid phase soldering[J]. J. Alloys Compd., 2017, 692: 552
[12] Zhao H Y, Liu J H, Li Z L, et al.Non-interfacial growth of Cu3Sn in Cu/Sn/Cu joints during ultrasonic-assisted transient liquid phase soldering process[J]. Mater. Lett., 2017, 186: 283
[13] Ji H J, Qiao Y F, Li M Y.Rapid formation of intermetallic joints through ultrasonic-assisted die bonding with Sn-0.7Cu solder for high temperature packaging application[J]. Scr. Mater., 2016, 110: 19
[14] Li Z L, Li M Y, Xiao Y, et al.Ultrarapid formation of homogeneous Cu6Sn5 and Cu3Sn intermetallic compound joints at room temperature using ultrasonic waves[J]. Ultrason. Sonochem., 2014, 21: 924
[15] Li J F, Agyakwa P A, Johnson C M.Interfacial reaction in Cu/Sn/Cu system during the transient liquid phase soldering process[J]. Acta Mater., 2011, 59: 1198
[16] Li M Y, Li Z L, Xiao Y, et al.Rapid formation of Cu/Cu3Sn/Cu joints using ultrasonic bonding process at ambient temperature[J]. Appl. Phys. Lett., 2013, 102: 094104
[17] Xu Z W, Yan J C, Zhang B Y, et al.Behaviors of oxide film at the ultrasonic aided interaction interface of Zn-Al alloy and Al2O3p/6061Al composites in air[J]. Mater. Sci. Eng., 2006, A415: 80
[18] Chinnam R K, Fauteux C, Neuenschwander J, et al.Evolution of the microstructure of Sn-Ag-Cu solder joints exposed to ultrasonic waves during solidification[J]. Acta Mater., 2011, 59: 1474
[19] Hang C J, Tian Y H, Zhang R, et al.Phase transformation and grain orientation of Cu-Sn intermetallic compounds during low temperature bonding process[J]. J. Mater. Sci. Mater. Electron., 2013, 24: 3905
[20] Choudhury S F, Ladani L.Grain growth orientation and anisotropy in Cu6Sn5 intermetallic: Nanoindentation and electron backscatter diffraction analysis[J]. J. Electron. Mater., 2014, 43: 996
[21] Yang P F, Lai Y S, Jian S R, et al.Nanoindentation identifications of mechanical properties of Cu6Sn5, Cu3Sn, and Ni3Sn4 intermetallic compounds derived by diffusion couples[J]. Mater. Sci. Eng., 2008, A485: 305
[22] Mu D, Huang H, Nogita K.Anisotropic mechanical properties of Cu6Sn5 and (Cu, Ni)6Sn5 [J]. Mater. Lett., 2012, 86: 46
[23] Chu K M, Sohn Y, Moon C.A comparative study of Cn/Sn/Cu and Ni/Sn/Ni solder joints for low temperature stable transient liquid phase bonding[J]. Scr. Mater., 2015, 109: 113
[24] Choudhury S F, Ladani L.Local shear stress-strain response of Sn-3.5Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis[J]. J. Alloys Compd., 2016, 680: 665
[25] Hansen N.Hall-Petch relation and boundary strengthening[J]. Scr. Mater., 2004, 51: 801
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