Release Time:2019-03-11  Hits:

Indexed by: Conference Paper

Date of Publication: 2013-08-11

Included Journals: Scopus、CPCI-S、EI

Page Number: 126-129

Key Words: liquid-solid electromigration (L-S EM); Sn-9Zn solder; intermetallic compound (IMC); reverse polarity effect; synchrotron radiation real-time in situ imaging technology

Abstract: Synchrotron radiation real-time in situ imaging technology was conducted to investigate the interfacial reaction in line-type Cu/Sn-9Zn/Cu interconnect under a current density of 1.2x10(4) A/cm(2) at 250 degrees C. A reverse polarity effect, i.e., the intermetallic compound (IMC) layer at the cathode grew continuously while that at the anode was restrained, was observed in Cu/Sn-9Zn/Cu interconnects. With increasing liquid-solid electromigration (L-S EM) time, the initial interfacial Cu5Zn8 gradually transformed into Cu-6(Sn,Zn)(5) at the anode, while into a mixture of Cu5Zn8 and Cu-6(Sn,Zn)(5) at the cathode. This provided a clear evidence that Zn atoms were migrating from the anode toward the cathode undergoing L-S EM, which is different from the normal diffusion behavior of atoms. Since there is no back-stress undergoing L-S EM, it is deduced that the effective charge number (Z*) of Zn atoms became positive, resulting in the directional migration of Zn atoms from the anode toward the cathode under electron current stressing.