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Indexed by:期刊论文

Date of Publication:2017-06-01

Journal:JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS

Included Journals:SCIE、EI

Volume:28

Issue:12

Page Number:8824-8831

ISSN No.:0957-4522

Abstract:Fluorescence X-ray Absorption Fine Structure (XAFS) was used to in situ study the local structure around Cu atoms in liquid Sn solder during Sn/Cu liquid-solid interfacial reaction. The extended edge data were analyzed by cumulant expansion method. The results showed that both the atomic distance and the coordination number in the first shell decreased with the increase of temperature. It is an intrinsic trend that high-coordinated polyhedrons could transform into low-coordinated ones with relatively high stability in the liquid Sn solder with increasing temperature, and the high-coordinated polyhedrons always had larger atomic distance. The atomic distance in the first shell decreased with decreasing coordination number. Based on the fitting results, the proportion of Cu-Sn atomic coordination increased with rising soldering temperature from 250 to 310 degrees C. That is, Cu atoms preferred to form Cu-Sn interaction with Sn atoms, which promoted the nucleation and growth of Cu6Sn5 intermetallic compound at the Sn/Cu interface during soldering process.