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Interfacial Reactions of Sn-Zn, Sn-Zn-Al, and Sn-Zn-Bi Solder Balls with Au/Ni Pad in BGA Package

The interfacial reactions of Sn-Zn and Sn-Zn-Al solder balls with Au/Ni surface finish under aging at 150¢J were investigated. With microstructure evolution, quantitative analysis, elemental distribution by X-ray color mapping from an electron probe microanalyzer (EPMA), the reaction procedure of phase transformation was proposed. During the reflow, Au dissolved into the solder balls and reacted with Zn to form £^-Au3Zn7. As aging time increased, £^-Au3Zn7 transformed to £^3-AuZn4. Finally, Zn precipitated near the Au-Zn intermetallic compound. On the other hand, Zn reacted with the Ni layer and formed Ni5Zn21. But the Al-Au-Zn IMC formed at the interface of Sn-Zn-Al solder balls, the reaction of Ni with Zn was inhibited. Even though the aging time increased to 50 days, no Ni5Zn21 was observed.
The Joule effect was more apparent than the electromigration in the biased solder balls. First of all, the new phase (Au, Ni)Zn4 was proposed in the biased condition and in 175¢Jaging. Secondly, the thickness of the Ni5Zn21 IMC were the same between the anode and the cathode. Finally, We directly measure the temperature of the biased solder balls which was up to 173¢J.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0616105-202317
Date16 June 2005
CreatorsChang, Shih-Chang
ContributorsKer-Chang Hsieh, Pou-Yan Shen, Der-Shih Gan
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0616105-202317
Rightsnot_available, Copyright information available at source archive

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