DocumentCode :
2312681
Title :
A study on the soldering reaction between Sn3Ag0.5Cu and electrolytic-Ni coated with a Au/Pd(P) bilayer surface finish
Author :
Wu, W.H. ; Chung, H.L. ; Lee, Nico ; Peng, Robert ; Ho, C.E.
Author_Institution :
Dept. of Chem. Eng. & Mater. Sci., Yuan Ze Univ., Taiwan
fYear :
2010
fDate :
20-22 Oct. 2010
Firstpage :
1
Lastpage :
4
Abstract :
The Ni-P alloy [or Ni(P)] with a 6-13 wt.% P content is a very common surface finishing material used in microelectronic packages. When a high P-content Ni(P) finish (≃13 wt.%) was jointed to the Sn-based solders, there are several possible P-containing intermetallics, e.g., Ni2SnP, Ni2P, Ni12P5, and Ni3P, can form at the interface. Among these intermetallics, the Ni2SnP layer played a major role in intermetallic compound (IMC) spalling behavior that has become a serious reliability concern of solder joints. Very recently, we found that the Ni2SnP can also form in a low P-content Ni(P) case (≃7 wt.%) if an additional Pd(P) layer was deposited above. It is hypothesized that the P element within the Ni2SnP resulted from the separation of P atoms from the Pd(P) layer as the Pd was converted into PdSn4 [or (Pd, Ni)Sn4] during soldering. The remaining P then reacted with Ni and Sn, forming a Ni2SnP layer at the interface. However, there is no direct proof to support this view. To simply the solder/Au/Pd(P)/Ni(P) interfacial reaction and to clarify the validity of the Ni2SnP formation mechanism aforementioned, soldering reactions between a Sn3Ag0.5Cu (96.5 wt.% Sn -3 wt.% Ag -0.5 wt.% Cu) alloy and a Au/Pd(P)/electrolytic-Ni tri-layer structure were investigated in this study. The results of this study showed that a layer of P-containing compound grew at the interface immediately after the Pd was converted into (Pd, Ni)Sn4. This verified the hypothesis made previously. A more detailed analysis on the reaction kinetics about the Sn3Ag0.5Cu alloy with the Au/Pd(P)/electrolytic-Ni, and the possible reliability concern arising from the Pd(P) layer will be presented in this study.
Keywords :
electronics packaging; nickel alloys; phosphorus alloys; soldering; solders; surface finishing; bilayer surface finish; hypothesis; interfacial reaction; intermetallic compound spalling behavior; microelectronic package; reaction kinetics; reliability; solder joint; soldering reaction; surface finishing material; Copper; Gold; Intermetallic; Nickel; Soldering; Tin; (Pd, Ni)Sn4; Au/Pd(P)/electrolytic-Ni; IMC massive spalling; Ni2SnP; Sn3Ag0.5Cu; interfacial reaction;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Microsystems Packaging Assembly and Circuits Technology Conference (IMPACT), 2010 5th International
Conference_Location :
Taipei
ISSN :
2150-5934
Print_ISBN :
978-1-4244-9783-6
Electronic_ISBN :
2150-5934
Type :
conf
DOI :
10.1109/IMPACT.2010.5699578
Filename :
5699578
Link To Document :
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