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Title: Electromigration induced Kirkendall void growth in Sn-3.5Ag/Cu solder joints

Effects of electric current flow on the Kirkendall void formation at solder joints were investigated using Sn-3.5Ag/Cu joints specially designed to have localized nucleation of Kirkendall voids at the Cu{sub 3}Sn/Cu interface. Under the current density of 1 × 10{sup 4} A/cm{sup 2}, kinetics of Kirkendall void growth and intermetallic compound thickening were affected by the electromigration (EM), and both showed the polarity effect. Cu{sub 6}Sn{sub 5} showed a strong susceptibility to the polarity effect, while Cu{sub 3}Sn did not. The electromigration force induced additional tensile (or compressive) stress at the cathode (or anode), which accelerated (or decelerated) the void growth. From the measurements of the fraction of void at the Cu{sub 3}Sn/Cu interface on SEM micrographs and analysis of the kinetics of void growth, the magnitude of the local stress induced by EM was estimated to be 9 MPa at the anode and −7 MPa at the cathode.
Authors:
;  [1]
  1. Department of Materials Science and Engineering, Electronic Packaging Laboratory, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22277966
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANODES; CATHODES; COPPER; CURRENT DENSITY; ELECTRIC CURRENTS; ELECTROPHORESIS; INTERFACES; INTERMETALLIC COMPOUNDS; NUCLEATION; PRESSURE RANGE MEGA PA; SCANNING ELECTRON MICROSCOPY; SILVER ALLOYS; SOLDERED JOINTS; STRESSES; TIN ALLOYS