Characterization of Cu₃P phase in Sn3.0Ag0.5Cu0.5P/Cu solder joints

Abstract

This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.5Cu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interfacial microstructure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like Cu₃P phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear testing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.

Keywords

lead-free solders / phosphorus / melting temperature / microstructure / thermodynamics

References

[1] Zou CD, Gao YL, Yang B, Zhai QJ. Melting and solidification properties of the nanoparticles of Sn3.0Ag0.5Cu lead-free solder alloy. Mater. Charact., 2010, 61(4): 474.

[2] Dong MJ, Gao ZM, Liu YC, Wang X, Yu LM. Effect of indium addition on the microstructural formation and soldered interfaces of Sn-2.5Bi-1Zn-0.3Ag lead-free solder. Int. J. Miner. Metall. Mater., 2012, 19(11): 1029.

[3] Rao BSSC, Kumar KM, Kripesh V, Zeng KY. Tensile deformation behavior of nano-sized Mo particles reinforced SnAgCu solders. Mater. Sci. Eng. A, 2011, 528(12): 4166.

[4] Wang MN, Wang JQ, Feng H, Wei K. Effects of microstructure and temperature on corrosion behavior of Sn-3.0Ag-0.5Cu lead-free solder. J. Mater. Sci. Mater. Electron., 2012, 23(1): 148.

[5] Ma YZ, Cui P, Liu WS, Peng F, Huang GJ. Film formation mechanism of coated SnAgCu alloy powders via vacuum evaporation. J. Univ. Sci. Technol. Beijing, 2011, 33(2): 188

[6] Cho SW, Han K, Yi Y, Kang SJ, Yoo KH, Jeong K, Whang CN. Thermal oxidation study on lead-free solders of Sn-Ag-Cu and Sn-Ag-Cu-Ge. Adv. Eng. Mater., 2006, 8(1–2): 111

[7] Padilla E, Jakkali V, Jiang L, Chawla N. Quantifying the effect of porosity on the evolution of deformation and damage in Sn-based solder joints by X-ray microtomography and microstructure-based finite element modeling. Acta Mater., 2012, 60(9): 4017.

[8] Xian AP, Gong GL. Oxidation behavior of molten tin doped with phosphorus. J. Electron. Mater., 2007, 36(12): 1669.

[9] Xia YH, Xie XM, Lu CY. Intermetallic compounds evolution between lead-free solder and cu-based lead frame alloys during isothermal aging. J. Mater. Sci., 2006, 41(8): 2359.

[10] Amagai M. A study of nanoparticles in Sn-Ag based lead free solders. Microelectron. Reliab., 2008, 48(1): 1.

[11] Li YN, Wang CW, Peng ZL, Yan JC, Liu XS. Dissolution behavior of Cu in Cu-Ag and Cu-P brazing alloys using weld brazing. Trans. Nonferrous Met. Soc. China, 2011, 21(Suppl.2): s394.

[12] Gao F, Xu WL, Wang C, Zou JS. Strength and microstructure of Cu joints brazed with Cu-P based amorphous filler metal contained Zr. Trans. China Weld. Inst., 2011, 32(10): 53

[13] Huang HZ, Wei XQ, Shuai GW, Zhou L. Study on the properties of Sn-9Zn-_xP lead-free solder alloy. J. Mater. Eng., 2010 4

[14] Huang HZ, Wei XQ, Tan DQ, Zhou L. Effects of phosphorus addition on the properties of Sn-9Zn lead-free solder alloy. Int. J. Miner. Metall. Mater., 2013, 20(6): 563.

[15] Shnawah DAA, Said SBM, Sabri MFM, Badruddin IA, Che FX. Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications. Mater. Sci. Eng. A, 2012, 551, 160.

[16] Tang WM, He AQ, Liu Q, Ivey DG. Solid state interfacial reactions in electrodeposited Ni/Sn couples. Int. J. Miner. Metall. Mater., 2010, 17(4): 459.

[17] Liu B, Guo F. Electrical conductivity changes of bulk tin and Sn-3.0Ag-0.5Cu in bulk and in joints during isothermal aging. Int. J. Miner. Metall. Mater., 2010, 17(4): 453.

[18] Park MS, Arróyave R. Early stages of intermetallic compound formation and growth during lead-free soldering. Acta Mater., 2010, 58(14): 4900.

[19] Hao H, Tian J, Shi YW, Lei YP, Xia ZD. Properties of Sn3.8Ag0.7Cu solder alloy with trace rare earth element Y additions. J. Electron. Mater., 2007, 36(7): 766.

[20] Prakash KH, Sritharan T. Effects of solid-state annealing on the interfacial intermetallics between tin-lead solders and copper. J. Electron. Mater., 2003, 32(9): 939.

[21] Massalski TB, Okamoto H, Subramanian PR, Kacprzak L. Binary Alloy Phase Diagrams, 1990 2nd Eds. Ohio, ASM International, 1451