Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2015-01-15

Journal: MATERIALS LETTERS

Included Journals: Scopus、EI、SCIE

Volume: 139

Page Number: 42-45

ISSN: 0167-577X

Key Words: Synchrotron radiation; Crystal growth; Intermetallic alloys and compounds; Precipitation; Dissolution; Cu6Sn5

Abstract: Synchrotron radiation real-time imaging technology was used for in situ study of dissolution and growth behavior of interfacial Cu6Sn5 intermetallic compound (IMC) in Sn/Cu solder interconnect during reflow soldering. The pre-formed Cu6Sn5 grains dissolved into the liquid solder with decreasing aspect ratio in the heating stage, maintained a thin layer of scallop-type in the dwelling stage, and re-precipitated on the existing Cu6Sn5 grains at a faster growth rate with increasing aspect ratio in the cooling stage. The Cu concentration gradient at the interface is responsible for the aspect ratio variation (corresponding to dissolution and re-precipitation of interfacial Cu6Sn5 grains), which is also supported by the simulation of atomic diffusion in the solder based on Fick's second law. The growth behavior was well explained by a proposed model based on the Cu concentration gradient. (C) 2014 Elsevier B.V. All rights reserved