Effect of Bi addition on the activation energy for the growth of Cu5Zn8 intermetallic in the Sn–Zn lead-free solder

Abstract The growth kinetics of Cu 5 Zn 8 phase has been investigated under long-term thermal exposure conditions using single shear lap joints. The Cu 5 Zn 8 phase was formed by reacting Sn–Zn and Sn–Zn–Bi lead-free solders with Cu substrate. A scanning electron microscope (SEM) was used to observe the morphology of the phases and energy dispersive X-ray (EDX) was used to estimate the elemental compositions of the phases. The morphology of the Cu 5 Zn 8 phase is rather flat for all the aging temperatures. The Cu 6 Sn 5 isolated phase was observed after long-term aging. Intermetallic thickness measurements show that the thickness of the Cu 5 Zn 8 phase in the Sn–8Zn–3Bi/Cu system is lower than in the Sn–9Zn/Cu system. Subsequently the activation energy for the growth of Cu 5 Zn 8 intermetallic is higher in the presence of Bi. Therefore, the presence of Bi in the Sn-matrix lowers the Zn diffusion and hampers the higher-growth of intermetallics in the Sn–8Zn–3Bi/Cu system compare to the Sn–9Zn/Cu solder interface.

[1]  Hyuck-Mo Lee,et al.  Interfacial reaction between Sn-1Bi-5In-9Zn solder and Cu substrate , 1999 .

[2]  Dae-Gon Kim,et al.  Solid state intermetallic compound layer growth between Sn-8Zn-3Bi solder and bare copper substrate , 2005 .

[3]  Jie Zhao,et al.  Influence of Bi on microstructures evolution and mechanical properties in Sn–Ag–Cu lead-free solder , 2004 .

[4]  Thirumany Sritharan,et al.  Interface reaction between copper and molten tin–lead solders , 2001 .

[5]  W. Gust,et al.  Intermetallic phase formation in thin solid-liquid diffusion couples , 1994 .

[6]  Seung-Boo Jung,et al.  Kinetics of intermetallic compound layer growth and interfacial reactions between Sn–8Zn–5In solder and bare copper substrate , 2005 .

[7]  Seung-Boo Jung,et al.  Investigation of interfacial reactions between Sn-5Bi solder and Cu substrate , 2003 .

[8]  Haoran Ma,et al.  Microstructural evolution of Sn–9Zn–3Bi solder/Cu joint during long-term aging at 170 °C , 2004 .

[9]  Y. C. Chan,et al.  Investigations of interfacial reactions of Sn–Zn based and Sn–Ag–Cu lead-free solder alloys as replacement for Sn–Pb solder , 2005 .

[10]  C. Wei,et al.  Evolution of intermetallic compounds layers in the soldered Sn–3.7Ag–1.0In–0.9Zn/Cu interface , 2009 .

[11]  Fuh-Sheng Shieu,et al.  Growth of intermetallic compounds in the Sn-9Zn/Cu joint , 2006 .

[12]  D. Frear.  The Mechanics of Solder Alloy Interconnects , 1993 .

[13]  Z. Ahmad,et al.  Effect of sample perimeter and temperature on Sn–Zn based lead-free solders , 2006 .

[14]  King-Ning Tu,et al.  Three‐dimensional morphology of a very rough interface formed in the soldering reaction between eutectic SnPb and Cu , 1995 .

[15]  J. Shang,et al.  Effect of Interface Roughness on Fatigue Crack Growth in Sn-Pb Solder Joints , 1996 .

[16]  Sinn-wen Chen,et al.  Interfacial reactions in the Sn-Ag/Au couples , 2001 .

[17]  M. Hon,et al.  Effects of process parameters on the soldering behavior of the eutectic Sn-Zn solder on Cu substrate , 2000 .

[18]  Kai Qi,et al.  Intermetallic compound formation at Sn–3.0Ag–0.5Cu–1.0Zn lead-free solder alloy/Cu interface during as-soldered and as-aged conditions , 2007 .

[19]  Hyuck-Mo Lee,et al.  Thermodynamic prediction of interface phases at Cu/solder joints , 1998 .

[20]  Wei-Kai Liou,et al.  Phase equilibria of the Au–Sn–Zn ternary system and interfacial reactions in Sn–Zn/Au couples , 2009 .

[21]  R. A. Fournelle,et al.  An improved numerical method for predicting intermetallic layer thickness developed during the formation of solder joints on Cu substrates , 1999 .

[22]  Zhaonian Cheng,et al.  Study of interfacial reactions in Sn–3.5Ag–3.0Bi and Sn–8.0Zn–3.0Bi sandwich structure solder joint with Ni(P)/Cu metallization on Cu substrate , 2007 .

[23]  Yiyu Qian,et al.  Improvement of microstructure and interface structure of eutectic Sn–0.7Cu solder with small amount of Zn addition , 2005 .

[24]  Zhiming Gao,et al.  Effect of the addition of In on the microstructural formation of Sn-Ag-Zn lead-free solder , 2008 .

[25]  K. N. Subramanian,et al.  Characterization of the growth of intermetallic interfacial layers of Sn-Ag and Sn-Pb eutectic solders and their composite solders on Cu substrate during isothermal long-term aging , 1999 .

[26]  Kwang-Lung Lin,et al.  Evolution of interfacial morphology of Sn-8.5Zn-0.5Ag-0.1Al-xGa/Cu system during isothermal aging , 2008 .

[27]  Sinn-wen Chen,et al.  Interfacial reactions in Sn–(Cu)/Cu6Sn5/Ni couples at 210 °C , 2008 .

[28]  Hyuck-Mo Lee,et al.  Prediction of interface reaction products between Cu and various solder alloys by thermodynamic calculation , 1997 .

[29]  Y. Liu,et al.  Intermediate decomposition of metastable Cu5Zn8 phase in the soldered Sn–Ag–Zn/Cu interface , 2008 .

[30]  Z. Ahmad,et al.  The effect of crosshead speed on the joint strength between Sn-Zn-Bi lead-free solders and Cu substrate , 2007 .

[31]  C. Wei,et al.  Microstructures of eutectic Sn–Ag–Zn solder solidified with different cooling rates , 2008 .

[32]  M. Abtew,et al.  Lead-free Solders in Microelectronics , 2000 .

[33]  Tao-Chih Chang,et al.  Formation and morphology of the intermetallic compounds formed at the 91Sn–8.55Zn–0.45Al lead-free solder alloy/Cu interface , 2005 .

[34]  Won Kyoung Choi,et al.  Effect of soldering and aging time on interfacial microstructure and growth of intermetallic compounds between Sn-3.5Ag solder alloy and Cu substrate , 2000 .

[35]  Koichi Niihara,et al.  Wetting and interface microstructure between Sn–Zn binary alloys and Cu , 1998 .

[36]  Seung Wook Yoon,et al.  Thermodynamics-aided alloy design and evaluation of Pb-free solder, Sn-Bi-In-Zn system , 1997 .

[37]  Hyungsuk K. D. Kim,et al.  Spalling of Cu6Sn5 spheroids in the soldering reaction of eutectic SnPb on Cr/Cu/Au thin films , 1996 .

[38]  S. Jung,et al.  Solid-state interfacial reactions between Sn–3.5Ag–0.7Cu solder and electroless Ni-immersion Au substrate during high temperature storage test , 2007 .

[39]  Russell F. Pinizzotto,et al.  Activation energies of intermetallic growth of Sn-Ag eutectic solder on copper substrates , 1997 .

[40]  M. Hon,et al.  The adhesion strength of A lead-free solder hot-dipped on copper substrate , 2000 .

[41]  Tomi Laurila,et al.  Interfacial reactions between lead-free solders and common base materials , 2005 .

[42]  C. Kao,et al.  Strong Zn concentration effect on the soldering reactions between Sn-based solders and Cu , 2006 .

[43]  C. Thwaites,et al.  Tin and its alloys and compounds , 1983 .

[44]  S. Fujiuchi,et al.  Interface Reaction and Mechanical Properties of Lead-free Sn-Zn Alloy/Cu Joints , 2002 .

[45]  Tao-Chih Chang,et al.  Kinetics of intermetallic compound formation at 91Sn–8.55Zn–0.45Al lead-free solder alloy/Cu interface , 2004 .

[46]  Tao-Chih Chang,et al.  Growth and morphology of the intermetallic compounds formed at the Sn–9Zn–2.5Ag/Cu interface , 2005 .

[47]  K. Suganuma,et al.  Sn–Zn low temperature solder , 2006 .

[48]  Kim,et al.  Kinetic analysis of the soldering reaction between eutectic SnPb alloy and Cu accompanied by ripening. , 1996, Physical review. B, Condensed matter.

[49]  D. Frear,et al.  Wetting reaction versus solid state aging of eutectic SnPb on Cu , 2001 .

[50]  M. Fine,et al.  Thickening kinetics of interfacial Cu6Sn5 and Cu3Sn layers during reaction of liquid tin with solid copper , 2003 .

[51]  Min-Hsiung Hon,et al.  Phase transformation and morphology of the intermetallic compounds formed at the Sn–9Zn–3.5Ag/Cu interface in aging , 2008 .

[52]  D. Q. Yu,et al.  Investigation of interfacial microstructure and wetting property of newly developed Sn–Zn–Cu solders with Cu substrate , 2004 .

[53]  K. Suganuma,et al.  Interfaces in lead-free soldering , 2003 .

[54]  Katsuaki Suganuma,et al.  Heat resistance of Sn-9Zn solder/Cu interface with or without coating , 2000 .

[55]  Jenn-Ming Song,et al.  Role of Ag in the formation of interfacial intermetallic phases in Sn-Zn soldering , 2005 .

[56]  D. R. Frear,et al.  The mechanical behavior of interconnect materials for electronic packaging , 1996 .

[57]  Y. G. Lee,et al.  Characterizing the formation and growth of intermetallic compound in the solder joint , 1998 .