Effect of Ni–P thickness on solid-state interfacial reactions between Sn–3.5Ag solder and electroless Ni–P metallization on Cu substrate

The interfacial reactions of Sn–Zn based solder on Cu and Cu/Ni–P/Cu–plating substrates under aging at 150 °C were investigated in this study. The compositions of solders investigated were Sn–9Zn, Sn–8.55Zn–0.45Al, and Sn–8.55Zn–0.45Al–0.5Ag solders in weight percent. The experimental results indicated that the Cu substrate formed Cu5Zn8 with the Sn–9Zn solder and Al–Cu–Zn compound with Al–containing solders. However, it was detected that Cu6Sn5 formed at the Sn–9Zn/Cu interface and Cu5Zn8 formed at the Al–containing solders/Cu interface after aging for 1000 h. When it contacted with the Cu/Ni–P/Au substrate, the Sn–9Zn solder formed Au–Zn compound, and the Al–containing solders formed Al–Cu–Zn compound at the interface. After a long aging time, the intermetallic compounds existing between solders and the Cu/Ni–P/Au metallization layers almost did not grow. It was found that the interdiffusion between solders and Cu/Ni–P/Au was slower than that with Cu under aging. Furthermore, the addition of Ag to Sn–Zn solder resulted in the formation of AgZn3 particles at the interface.

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Solid-state interfacial reactions of Sn and Sn–Ag–Cu solders with an electroless Co(P) layer deposited on a Cu substrate

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2015.12.060 ◽

2016 ◽

Vol 662 ◽

pp. 475-483 ◽

Cited By ~ 22

Author(s):

Chao-hong Wang ◽

Chun-chieh Wen ◽

Che-yang Lin

Keyword(s):

Solid State ◽

Interfacial Reactions ◽

Cu Substrate

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Microstructural evolution and interfacial reactions of fluxless-bonded Au-20Sn/Cu solder joint during reflow and aging

Journal of Materials Research ◽

10.1557/jmr.2007.0352 ◽

2007 ◽

Vol 22 (10) ◽

pp. 2817-2824 ◽

Cited By ~ 11

Author(s):

Jeong-Won Yoon ◽

Hyun-Suk Chun ◽

Hoo-Jeong Lee ◽

Seung-Boo Jung

Keyword(s):

High Temperature ◽

Solid State ◽

Intermetallic Compound ◽

Solder Joint ◽

Microstructural Evolution ◽

Surface Finish ◽

Solder Matrix ◽

Interfacial Reactions ◽

Cu Substrate ◽

Study Results

The microstructural evolution and interfacial reactions of fluxless-bonded, Au-20wt%Sn/Cu solder joint were investigated during reflow and aging. After reflowing at 310 °C, only one thick and irregularly shaped ζ(Cu) layer was formed at the interface. After the prolonged reflow reaction, the AuCu layer was formed between the ζ(Cu) layer and the Cu substrate. During reflowing, the Cu substrate reacted primarily with the ζ-phase in the solder matrix. The solid-state interfacial reaction was much faster at 250 °C than at 150 °C. After aging at 250 °C for 100 h, thick ζ(Cu), AuCu and AuCu3 IMC layers were formed at the interface. The formation of the AuCu3 intermetallic compound (IMC) was caused by Cu enrichment at the AuCu/Cu layer interface. After aging for 500 h, cracks were observed inside the interfacial AuCu layer. The study results clearly demonstrate the need for an alternative surface finish on Cu, to ensure the high temperature reliability of the Au-20Sn/Cu solder joint.

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Influence of solid-state interfacial reactions on the tensile strength of Cu/electroless Ni–P/Sn–3.5Ag solder joint

Materials Science and Engineering A ◽

10.1016/j.msea.2005.12.040 ◽

2006 ◽

Vol 423 (1-2) ◽

pp. 175-179 ◽

Cited By ~ 19

Author(s):

Aditya Kumar ◽

Zhong Chen

Keyword(s):

Tensile Strength ◽

Solid State ◽

Solder Joint ◽

Interfacial Reactions ◽

Electroless Ni

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Growth Kinetics of IMC Formed between Sn-3.5Ag-0.75Cu BGA Solder and Electroless Ni-P/Cu Substrate by Solid-State Isothermal Aging

Materials Science Forum ◽

10.4028/www.scientific.net/msf.449-452.893 ◽

2004 ◽

Vol 449-452 ◽

pp. 893-896 ◽

Cited By ~ 1

Author(s):

Jeong Won Yoon ◽

Chang Bae Lee ◽

Seung Boo Jung

Keyword(s):

Solid State ◽

Growth Kinetics ◽

Isothermal Aging ◽

Ball Grid Array ◽

Cu Substrate ◽

Diffusion Controlled ◽

Increasing Temperature ◽

Electroless Ni ◽

Kinetics Of ◽

Deposit Layer

The growth kinetics of intermetallic compound (IMC) layers formed between Sn-3.5Ag-0.75Cu BGA (ball grid array) solder and electroless Ni-P/Cu substrate by solid state isothermal aging were examined at temperatures between 70 and 170°C for 0 to 100 days. In the solder joints between the solder ball and electroless Ni-P/Cu pads, the IMC layer was (Cu,Ni)6Sn5. Also, a P-rich Ni layer formed at the interface between (Cu,Ni)6Sn5 and original Ni-P deposit layer because of the phosphorous accumulation. These IMC layer thicknesses increased linearly with the square root of aging time and the growth was faster for higher aging temperatures. On the contrary, the shear strength decreased with the increasing temperature and time. The growth of IMC layer was mainly controlled by diffusion-controlled mechanism over the temperature range studied. The apparent activation energy calculated for the growth of the (Cu,Ni)6Sn5 IMC was 69.75 kJ/mol.

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