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Indexed by:Journal Papers

Date of Publication:2015-11-13

Journal:JOURNAL OF MATERIALS RESEARCH

Included Journals:SCIE、EI、Scopus

Volume:30

Issue:21

Page Number:3316-3323

ISSN No.:0884-2914

Abstract:The interfacial reactions in Cu/Sn-52In/Cu interconnects during solid-solid (S-S) and liquid-solid (L-S) electromigration (EM) under a current density of 2.0 x 10(4) A/cm(2) at 90 and 150 degrees C have been in situ studied using synchrotron radiation real-time imaging technology. The In atoms directionally migrate toward the cathode due to the back-stress induced by the preferential migration of the Sn atoms over the In atoms toward the anode during the S-S EM, resulting in the segregation of the Sn and In atoms at the anode and cathode, respectively. During the L-S EM, however, the In atoms directionally migrate toward the anode due to the negative effective charge number (Z*) of In rather than the back-stress. The polarity effect, i.e., the intermetallic compounds growing continuously at the anode while becoming thinner at the cathode, is more significant during the L-S EM than the S-S EM. Furthermore, the consumption rate of the cathode Cu during the L-S EM is three orders of magnitude higher than that in the case of the S-S EM because of the significantly higher EM-induced atomic flux in the liquid solder. The migrations of the Sn, In, and Cu atoms are discussed in terms of diffusion flux.