Effects of phosphorus addition on the properties of Sn-9Zn lead-free solder alloy

Abstract

This article explores the effects of phosphorus addition on the wettability between Sn-9Zn solder alloy and Cu substrates, the oxidation behavior and the corrosion behavior of Sn-9Zn solder alloy. Spreading test was used to characterize the wettability of Sn-9Zn-xP solder alloys to Cu substrates. The oxidation and corrosion behaviors of Sn-9Zn-xP solder alloys were determined by means of weight gaining, and secondary ion mass spectrometry was used to analyze the oxygen content. The role and mechanism of P in the solder alloys were also discussed. It is found that the addition of P can significantly improve the wettability of the solder alloys. Incorporating P into Sn-9Zn solder alloy obviously decreases the oxygen content and enhances the oxidation and corrosion resistance. Microstructure observations show that an appropriate amount of P can greatly refine coarse rod-like Zn-rich phases in Sn-9Zn solder alloy.

Keywords

lead-free solder / phosphorus / wettability / oxidation / corrosion

References

[1] Abtew M, Selvaduray G. Lead-free solders in microelectronics. Mater. Sci. Eng. R, 2000, 27(5–6): 95.

[2] Yan YF, Wang YS, Feng LF, Song KX, Wen JB. Effect of Ag and Ni on the melting point and solderability of SnSbCu solder alloys. Int. J. Miner. Metall. Mater., 2009, 16(6): 691.

[3] Huang HZ, Wei XQ, Liao FP, Zhou L. Preparation and properties of particle reinforced Sn-Zn-based composite solder. J. Wuhan Univ. Technol. Mater. Sci. Ed., 2009, 24(2): 206.

[4] Suganuma K. Advances in lead-free electronics soldering. Curr. Opin. Solid State Mater. Sci., 2001, 5(1): 55.

[5] Wu CML, Law CMT, Yu DQ, Wang L. The wettability and microstructure of Sn-Zn-RE alloys. J. Electron. Mater., 2003, 32(2): 63.

[6] Prasad LC, Xie Y, Mikula A. Lead free solder materials In-Sn-Zn system. J. Non Cryst. Solids, 1999, 250–252(Part1): 316.

[7] Lin KL, Shih CL. Wetting interaction between Sn-Zn-Ag solders and Cu. J. Electron. Mater., 2003, 32(2): 95.

[8] Vaynman S, Fine ME. Development of fluxes for leadfree solders containing zinc. Scripta Mater., 1999, 41(12): 1269.

[9] Yu SP, Liao CL, Hon MH, Wang MC. The effects of flux on the wetting characteristics of near-eutectic Sn-Zn-In solder on Cu substrate. J. Mater. Sci., 2000, 35(17): 4217.

[10] Yu DQ, Xie HP, Wang L. Investigation of interfacial microstructure and wetting property of newly developed Sn-Zn-Cu solders with Cu substrate. J. Alloys Compd., 2004, 385(1–2): 119.

[11] Sharif A, Chan YC. Effect of substrate metallization on interfacial reactions and reliability of Sn-Zn-Bi solder joints. Microelectron. Eng., 2007, 84(2): 328.

[12] Huang HZ, Zhou L, Wei XQ, Ye ZT. Microstructures of solidified Sn-9Zn lead-free solder alloy and their evolution in aging. Mater. Sci. Technol., 2008, 16(3): 374.

[13] Kim YS, Kim KS, Hwang CW, Suganuma K. Effect of composition and cooling rate on microstructure and tensile properties of Sn-Zn-Bi alloys. J. Alloys Compd., 2003, 352(1–2): 237.

[14] Zhang L, Xue SB, Gao LL, Sheng Z, Ye H, Xiao ZX, Zeng G, Chen Y, Yu SL. Development of Sn-Zn lead-free solders bearing alloying elements. J. Mater. Sci. Mater. Electron., 2010, 21(1): 1.

[15] Lu WH, Li LS, Huang LY. Cast Alloy & Melting, 2006, Beijing, China Machine Press, 346.