Full Content is available to subscribers

Subscribe/Learn More  >

Electromigration in Copper-Core Solder Ball Joints During Thermal Cycle Tests

[+] Author Affiliations
Shinichi Fujiwara

Hitachi, Ltd., Yokohama, Kanagawa, Japan

Nobuhiko Chiwata

Hitachi Metals, Ltd., Tokyo, Japan

Masaru Fujiyoshi

Hitachi Metals, Ltd., Yasugi, Shimane, Japan

Motoki Wakano

Neomax Kagoshima Co., Ltd., Izumi, Kagoshima, Japan

Hisashi Tanie

Hitachi, Ltd., Hitachinaka, Ibaraki, Japan

Paper No. IPACK2011-52110, pp. 719-723; 5 pages
  • ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems
  • ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, MEMS and NEMS: Volume 2
  • Portland, Oregon, USA, July 6–8, 2011
  • ISBN: 978-0-7918-4462-5
  • Copyright © 2011 by ASME


Electromigration current densities in Cu and Al lines on a silicon die exceed 1.0 × 106 A/cm2 . However, solder joints can only withstand electromigration current densities below about 1.0 × 104 A/cm2 . Thus, electromigration in solder joints will become a problem in semiconductor packages in the near future. Previous studies demonstrated that Cu-core solder balls increased the electromigration lifetime and led to better current stability at temperatures below 423K. This is because electrons flow through the Cu cores, reducing the current density on the cathode side, which is where electromigration occurs. In the present study, we forcused on the reliability of solder joints in a combined environment by examining the effect of thermal cycle tests on the current in a new test sample. A new test sample for the evaluation of joining reliability by using Cu-core solder balls in a combined enbironment was made. In initial tests, this test sample exhibited similar results to those observed in previous studies. Cu-core solder balls subjected to cyclic testing at 233/398K and a current density of 1.0 × 104 A/cm2 exhibited lower reliabilities than when there was no current. Examination of cross-sections of the solder balls after reliability testing revealed that the combined environment accelerated growth of intermetallic compounds and cracks in the joining region. In a combined environment, Cu-core balls were converted into intermetallic compounds on the anode side. This phenomenon is thought to occur due to the different electrical resistivities of Cu-Sn intermetallic compounds.

Copyright © 2011 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In