Please wait a minute...
Acta Metall Sin  2017, Vol. 53 Issue (5): 615-621    DOI: 10.11900/0412.1961.2016.00332
Orginal Article Current Issue | Archive | Adv Search |
Microstructures Evolution and Properties of Sn-Ag-Cu Solder Joints
Lei SUN1,Minghe CHEN1(),Liang ZHANG2,Fan YANG2
1 College of Mechanical & Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
1 College of Mechanical & Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Cite this article: 

Lei SUN,Minghe CHEN,Liang ZHANG,Fan YANG. Microstructures Evolution and Properties of Sn-Ag-Cu Solder Joints. Acta Metall Sin, 2017, 53(5): 615-621.

Download:  HTML  PDF(5124KB) 
Export:  BibTeX | EndNote (RIS)      
Abstract  

SnAgCu solder alloys, such as Sn3.0Ag0.5Cu, Sn3.8Ag0.7Cu and Sn3.9Ag0.6Cu, are widely used for consumer electronics due to their good wettability, high mechanical properties and excellent thermal fatigue reliability. However, the high Ag content in SnAgCu solder can bring about a relatively high cost and poor drop impact reliability because of the formations of thicker brittle Ag3Sn compound during soldering. Therefore, the development of low Ag content SnAgCu solders to satisfy the requirements of electronic production has become a hot topic in this field. In this work, the effects of Sn0.3Ag0.7Cu, Sn1.0Ag0.5Cu and Sn3.0Ag0.5Cu solder on the melting character, wettability, mechanical properties and microstructures, phase composition were investigated by DSC, micro-joint strength tester, SEM, EDS and XRD. Under -55~125 ℃ cyclic conditions, the interfacial layer change of Sn-Ag-Cu solder joints was measured by TL-1000 high and low temperature test chamber. The results showed that, with the Ag content increased, the melting point was not changed, the wetting angle significantly decreased. And the wettability of three solders was improved under N2 atmosphere. Moreover, the mechanical properties of three solder joints were enhanced with the increase of Ag content. The matrix structure of Sn0.3Ag0.7Cu and Sn1.0Ag0.5Cu solder joint have a small amount of Ag3Sn and large Cu6Sn5 particles, and the distribution of particles were disordered. However, the matrix structure of Sn3.0Ag0.5Cu solder joint was obviously uniform. This is the reason that the mechanical properties of Sn0.3Ag0.7Cu and Sn1.0Ag0.5Cu solder joints were lower than that of Sn3.0Ag0.5Cu. In addition, the solder joints were subjected to a thermal cycling reliability test, it was found that the thickness of intermetallic compounds (IMCs) increased, and the morphology of IMCs was gradually changed from scallop-like to planar-like.

Key words:  Sn-Ag-Cu      wettability      mechanical property      microstructure      thermal cycling     
Received:  25 July 2016     
Fund: Supported by National Natural Science Foundation of China (No.51475220), Six Talent Peaks project in Jiangsu Province (No.XCL022), Qing Lan project, State Key Laboratory of Advanced Brazing Filler Metals & Technology (No.SKLABFMT201503) and China Postdoctoral Science Foundation Funded Project (No.2016M591464)

URL: 

https://www.ams.org.cn/EN/10.11900/0412.1961.2016.00332     OR     https://www.ams.org.cn/EN/Y2017/V53/I5/615

Fig.1  Reflow soldering curve of lead-free solder
Fig.2  Schematics of pull force of quad flat package (QFP) (a) and shear test of chip resistor (b) of Sn-Ag-Cu solder joint
Fig.3  Loading specification of temperature cycle
Solder TS TL Melting
range
Under-
cooling
Sn0.3Ag0.7Cu 213.0 228.1 15.1 22.6
Sn1.0Ag0.5Cu 213.7 227.7 14.0 17.8
Sn3.0Ag0.5Cu 213.4 219.7 6.3 8.3
Table 1  Melting temperatures of Sn-Ag-Cu solder(℃)
Fig.4  Wetting angles of Sn-Ag-Cu solders during different atmospheres
Fig.5  Mechanical properties of Sn-Ag-Cu solder joints
Fig.6  Fracture SEM images of Sn0.3Ag0.7Cu (a), Sn1.0Ag0.5Cu (b) and Sn3.0Ag0.5Cu (c)
Fig.7  SEM image (a), EDS elemental distribution map (b) and XRD spectrum (c) of Sn3.0Ag0.5Cu solder joint
Fig.8  SEM images of matrix structures of Sn0.3Ag0.7Cu (a), Sn1.0Ag0.5Cu (b) and Sn3.0Ag0.5Cu (c) solder joints
Fig.9  SEM images of interface layers of Sn0.3Ag0.7Cu (a), Sn1.0Ag0.5Cu (b) and Sn3.0Ag0.5Cu (c) solder joints
Fig.10  SEM images of interface layers of Sn0.3Ag0.7Cu (a), Sn1.0Ag0.5Cu (b) and Sn3.0Ag0.5Cu (c) solder joints after 500 cyc
Fig.11  IMC layer thickness of Sn- Ag- Cu solder joints during different ageing times
[1] Chen X, Zhou J, Xue F, et al.Mechanical deformation behavior and mechanism of Sn-58Bi solder alloys under different temperatures and strain rates[J]. Mater. Sci. Eng., 2016, A662: 251
[2] Xu S Y, Habib A H, Pickel A D, et al.Magnetic nanoparticle-based solder composites for electronic packaging applications[J]. Prog. Mater. Sci., 2015, 67: 95
[3] Jiang Z, Tian Y H, Ding S.Synthesis of Sn3.5Ag0.5Cu nanoparticle solders and soldering mechanism[J]. Acta Metall. Sin., 2016, 52: 105
[3] (江智, 田艳红, 丁苏. Sn3.5Ag0.5Cu纳米颗粒钎料制备及钎焊机理[J]. 金属学报, 2016, 52: 105)
[4] Chellvarajoo S, Abdullah M Z.Microstructure and mechanical properties of Pb-free Sn-3.0Ag-0.5Cu solder pastes added with NiO nanoparticles after reflow soldering process[J]. Mater. Des., 2016, 90: 499
[5] Chen X, Xue F, Zhou J, et al.Effect of In on microstructure, thermodynamic characteristic and mechanical properties of Sn-Bi based lead-free solder[J]. J. Alloys Compd., 2015, 633: 377
[6] Chen G, Wu F S, Liu C Q, et al.Microstructures and properties of new Sn-Ag-Cu lead-free solder reinforced with Ni-coated graphene nanosheets[J]. J. Alloys Compd., 2016, 656: 500
[7] Yang M, Ji H J, Wang S, et al.Effects of Ag content on the interfacial reactions between liquid Sn-Ag-Cu solders and Cu substrates during soldering[J]. J. Alloys Compd., 2016, 679: 18
[8] Luo D X, Xue S B, Li Z Q.Effects of Ga addition on microstructure and properties of Sn-0.5Ag-0.7Cu solder[J]. J. Mater. Sci. Mater. Electron., 2014, 25: 3566
[9] Hamada N, Uesugi T, Takigawa Y, et al.Effect of addition of small amount of Zinc on microstructural evolution and thermal shock behavior in low-Ag Sn-Ag-Cu solder joints during Thermal Cycling[J]. Mater. Trans., 2013, 54: 796
[10] Sun L, Zhang L, Xu L, et al.Effect of nano-Al addition on properties and microstructure of low-Ag content Sn-1Ag-0.5Cu solders[J]. J. Mater. Sci. Mater. Electron., 2016, 27: 7665
[11] Chen F J, Gao F, Zhang J Y, et al.Tensile properties and wettability of SAC0307 and SAC105 low Ag lead-free solder alloys[J]. J. Mater. Sci., 2011, 46: 3424
[12] Kanlayasiri K, Mongkolwongrojn M, Ariga T.Influence of indium addition on characteristics of Sn-0.3Ag-0.7Cu solder alloy[J]. J. Alloys Compd., 2009, 485: 225
[13] Wang C Q, Li M Y, Tian Y H, et al.Review of JIS Z 3198: test method for lead-free solders[J]. Electron. Process Technol., 2004, 25(2): 47
[13] (王春青, 李明雨, 田艳红等. JIS Z 3198无铅钎料试验方法简介与评述[J]. 电子工艺技术, 2004, 25(2): 47)
[14] Cheng Y K, Li L F, Xu G L.Effect of Ag on properties of Sn-0.7Cu-0.2Ni alloy solder[J]. J. Funct. Mater., 2013, 44: 384
[14] (程艳奎, 李良锋, 徐光亮. 微量Ag元素对Sn-0.7Cu-0.2Ni钎料性能的影响[J]. 功能材料, 2013, 44: 384)
[15] Zhang L, Fan X Y, Guo Y H, et al.Properties enhancement of SnAgCu solders containing rare earth Yb[J]. Mater. Des., 2014, 57: 646
[16] Wang J X, Xue S B, Huang X, et al.Effects of N2 protection on wettability of Sn-Cu-Ni-Ce lead-free solder[J]. Trans. China Weld. Inst., 2007, 28(1): 49
[16] (王俭辛, 薛松柏, 黄翔等. 氮气保护对Sn-Cu-Ni-Ce无铅钎料润湿性的影响[J]. 焊接学报, 2007, 28(1): 49)
[17] Ma X L.Research on SnAgCu solder alloys [D]. Beijing: Beijing University of Technology, 2004(马秀玲. SnAgCu系无铅钎料的研究 [D]. 北京: 北京工业大学, 2004)
[18] Zhang L, Han J G, Guo Y H, et al.Reliability of SnAgCu/SnAgCuCe solder joints with different heights for electronic packaging[J]. J. Mater. Sci. Mater. Electron., 2014, 25: 4489
[19] Yang L, Ge J G, Zhang Y C, et al.Effect of BaTiO3 on the microstructure and mechanical properties of Sn1.0Ag0.5Cu lead-free solder[J]. J. Mater. Sci. Mater. Electron., 2015, 26: 613
[20] El-Daly A A, Al-Ganainy G S, Fawzy A, et al. Structural characterization and creep resistance of nano-silicon carbide reinforced Sn-1.0Ag-0.5Cu lead-free solder alloy[J]. Mater. Des., 2014, 55: 837
[21] Gu Y, Zhao X C, Li Y, et al.Effect of nano-Fe2O3 additions on wettability and interfacial intermetallic growth of low-Ag content Sn-Ag-Cu solders on Cu substrates[J]. J. Alloys Compd., 2015, 627: 39
[22] Wu R W, Tsao L C, Chen R S.Effect of 0.5 wt% nano-TiO2 addition into low-Ag Sn0.3Ag0.7Cu solder on the intermetallic growth with Cu substrate during isothermal aging[J]. J. Mater. Sci. Mater. Electron., 2015, 26: 1858
[23] Ma L M, Xu G C, Sun J, et al.Electromigration effects on intermetallic compound layer growth in Sn-3.0Ag-0.5Cu-XCo solder joint[J]. Rare Met. Mater. Eng., 2011, 40(Suppl.): 438
[23] (马立民, 徐广臣, 孙嘉等. Sn-3.0Ag-0.5Cu-XCo钎焊接头金属间化合物层电迁移现象的研究[J]. 稀有金属材料与工程, 2011, 40(增刊): 438)
[24] Sun L, Zhang L, Zhong S J, et al.Reliability study of industry Sn3.0Ag0.5Cu/Cu lead-free soldered joints in electronic packaging[J]. J. Mater. Sci. Mater. Electron., 2015, 26: 9164
[25] Zhang L, Gao L L.Interfacial compounds growth of SnAgCu (nano La2O3)/Cu solder joints based on experiments and FEM[J]. J. Alloys Compd., 2015, 635: 55
[1] ZHANG Jian, WANG Li, XIE Guang, WANG Dong, SHEN Jian, LU Yuzhang, HUANG Yaqi, LI Yawei. Recent Progress in Research and Development of Nickel-Based Single Crystal Superalloys[J]. 金属学报, 2023, 59(9): 1109-1124.
[2] WANG Lei, LIU Mengya, LIU Yang, SONG Xiu, MENG Fanqiang. Research Progress on Surface Impact Strengthening Mechanisms and Application of Nickel-Based Superalloys[J]. 金属学报, 2023, 59(9): 1173-1189.
[3] GONG Shengkai, LIU Yuan, GENG Lilun, RU Yi, ZHAO Wenyue, PEI Yanling, LI Shusuo. Advances in the Regulation and Interfacial Behavior of Coatings/Superalloys[J]. 金属学报, 2023, 59(9): 1097-1108.
[4] ZHANG Leilei, CHEN Jingyang, TANG Xin, XIAO Chengbo, ZHANG Mingjun, YANG Qing. Evolution of Microstructures and Mechanical Properties of K439B Superalloy During Long-Term Aging at 800oC[J]. 金属学报, 2023, 59(9): 1253-1264.
[5] LU Nannan, GUO Yimo, YANG Shulin, LIANG Jingjing, ZHOU Yizhou, SUN Xiaofeng, LI Jinguo. Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys[J]. 金属学报, 2023, 59(9): 1243-1252.
[6] ZHENG Liang, ZHANG Qiang, LI Zhou, ZHANG Guoqing. Effects of Oxygen Increasing/Decreasing Processes on Surface Characteristics of Superalloy Powders and Properties of Their Bulk Alloy Counterparts: Powders Storage and Degassing[J]. 金属学报, 2023, 59(9): 1265-1278.
[7] DING Hua, ZHANG Yu, CAI Minghui, TANG Zhengyou. Research Progress and Prospects of Austenite-Based Fe-Mn-Al-C Lightweight Steels[J]. 金属学报, 2023, 59(8): 1027-1041.
[8] CHEN Liqing, LI Xing, ZHAO Yang, WANG Shuai, FENG Yang. Overview of Research and Development of High-Manganese Damping Steel with Integrated Structure and Function[J]. 金属学报, 2023, 59(8): 1015-1026.
[9] LI Jingren, XIE Dongsheng, ZHANG Dongdong, XIE Hongbo, PAN Hucheng, REN Yuping, QIN Gaowu. Microstructure Evolution Mechanism of New Low-Alloyed High-Strength Mg-0.2Ce-0.2Ca Alloy During Extrusion[J]. 金属学报, 2023, 59(8): 1087-1096.
[10] LIU Xingjun, WEI Zhenbang, LU Yong, HAN Jiajia, SHI Rongpei, WANG Cuiping. Progress on the Diffusion Kinetics of Novel Co-based and Nb-Si-based Superalloys[J]. 金属学报, 2023, 59(8): 969-985.
[11] SUN Rongrong, YAO Meiyi, WANG Haoyu, ZHANG Wenhuai, HU Lijuan, QIU Yunlong, LIN Xiaodong, XIE Yaoping, YANG Jian, DONG Jianxin, CHENG Guoguang. High-Temperature Steam Oxidation Behavior of Fe22Cr5Al3Mo-xY Alloy Under Simulated LOCA Condition[J]. 金属学报, 2023, 59(7): 915-925.
[12] YUAN Jianghuai, WANG Zhenyu, MA Guanshui, ZHOU Guangxue, CHENG Xiaoying, WANG Aiying. Effect of Phase-Structure Evolution on Mechanical Properties of Cr2AlC Coating[J]. 金属学报, 2023, 59(7): 961-968.
[13] WU Dongjiang, LIU Dehua, ZHANG Ziao, ZHANG Yilun, NIU Fangyong, MA Guangyi. Microstructure and Mechanical Properties of 2024 Aluminum Alloy Prepared by Wire Arc Additive Manufacturing[J]. 金属学报, 2023, 59(6): 767-776.
[14] GUO Fu, DU Yihui, JI Xiaoliang, WANG Yishu. Recent Progress on Thermo-Mechanical Reliability of Sn-Based Alloys and Composite Solder for Microelectronic Interconnection[J]. 金属学报, 2023, 59(6): 744-756.
[15] FENG Aihan, CHEN Qiang, WANG Jian, WANG Hao, QU Shoujiang, CHEN Daolun. Thermal Stability of Microstructures in Low-Density Ti2AlNb-Based Alloy Hot Rolled Plate[J]. 金属学报, 2023, 59(6): 777-786.
No Suggested Reading articles found!