The interfacial amorphous double layer and the homogeneous nucleation in reflow of a Sn-Zn solder on Cu substrate

To illustrate the interfacial reaction mechanism, the Sn-Zn[Sn–8.5Zn–0.5Ag-0.01Al-0.1Ga (wt%)] solder was reflowed on Cu substrate at 250 °C for 15 s followed by immediate quench in liquid nitrogen. The frozen interfacial microstructure was investigated with high resolution transmission electron microscope. An amorphous double layer was formed at the interface which consists of a 5 nm pure Cu region and a Cu-Zn diffusion region. Nanocrystalline intermetallic compound (IMC) Cu5Zn8 were observed in the Cu-Zn diffusion region. These nanocrystalline IMCs are suggested to form via a homogeneous nucleation process.

[1]  Kwang-Lung Lin,et al.  Sn-Zn-Al Pb-free solder—An inherent barrier solder for Cu contact , 2001 .

[2]  B. Salam,et al.  Suppressing Growth of the Cu5Zn8 Intermetallic Layer in Sn-Zn-Ag-Al-Ga/Cu Solder Joints , 2009 .

[3]  Kwang-Lung Lin,et al.  Microstructure and Mechanical Properties of Sn-8.55Zn-1Ag-XAl Solder Alloys , 2005 .

[4]  Kwang-Lung Lin,et al.  The amorphous origin and the nucleation of intermetallic compounds formed at the interface during the soldering of Sn-3.0Ag-0.5Cu on a Cu substrate , 2008 .

[5]  Kwang-Lung Lin,et al.  Interfacial evolution between Cu and Pb–free Sn–Zn–Ag–Al solders upon aging at 150 °C , 2003 .

[6]  D. T. Hawkins,et al.  Selected values of the thermodynamic properties of binary alloys , 1973 .

[7]  King-Ning Tu,et al.  Dramatic morphological change of scallop-type Cu6Sn5 formed on (001) single crystal copper in reaction between molten SnPb solder and Cu , 2007 .

[8]  Yee-Wen Yen,et al.  Interfacial reactions in Ag-Sn/Cu couples , 1999 .

[9]  Kwang-Lung Lin,et al.  The atomic-scale studies of the behavior of the crystal dissolution in a molten metal , 2006 .

[10]  K. Tu,et al.  Tin–lead (SnPb) solder reaction in flip chip technology , 2001 .

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

[12]  Kwang-Lung Lin,et al.  Early dissolution behavior of copper in a molten Sn–Zn–Ag solder , 2005 .

[13]  Kwang-Lung Lin,et al.  The microstructures and mechanical properties of the Sn-Zn-Ag-Al-Ga solder alloys—the effect of Ag , 2002 .

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

[15]  Zhi-Quan Liu,et al.  Directional growth of Cu3Sn at the reactive interface between eutectic SnBi solder and (100) single crystal Cu , 2008 .

[16]  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 .

[17]  J. Park,et al.  The analysis of the withdrawal force curve of the wetting curve using 63Sn-37Pb and 96.5Sn-3.5Ag eutectic solders , 1999 .

[18]  Kwang-Lung Lin,et al.  Early stage soldering reaction and interfacial microstructure formed between molten Sn-Zn-Ag solder and Cu substrate , 2005 .

[19]  Kwang-Lung Lin,et al.  The effect of Ga content on the wetting reaction and interfacial morphology formed between Sn–8.55Zn–0.5Ag–0.1Al–xGa solders and Cu , 2006 .

[20]  K. N. Subramanian,et al.  Effect of cooling rate on microstructure and mechanical properties of eutectic Sn-Ag solder joints with and without intentionally incorporated Cu6Sn5 reinforcements , 1999 .

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

[22]  M. Fine,et al.  Nucleation kinetics of Cu6Sn5 by reaction of molten tin with a copper substrate , 2002 .

[23]  Kwang-Lung Lin,et al.  The interfacial reaction between Sn-Zn-Ag-Ga-Al solders and metallized Cu substrates , 2004 .

[24]  N. Tamura,et al.  Preferred orientation relationship between Cu6Sn5 scallop-type grains and Cu substrate in reactions between molten Sn-based solders and Cu , 2007, Journal of Applied Physics.