Solder interconnection specimen design and test control procedure for valid constitutive modeling of solder alloys

D. Bhate, D. Chan, G. Subbarayan, T. C. Chiu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

10 Scopus citations

Abstract

Commonly, constitutive models of solder alloys are derived from mechanical tests performed on either bulk solder specimens or on specially assembled BGA test coupons where the stresses are borne by solder ball interconnects. It has been widely recognized that models derived from bulk sample test data may not be reliable when predicting deformation behavior at the solder interconnect level due to the differences in the inherent microstructures at these different scales. This is particularly critical for lead-free SnAgCu solder alloys owing to their complex microstructures. There are two primary challenges associated with developing models from solder interconnect level test data: the experimental complexity associated with accurately resolving and controlling displacement at the scale of the interconnection, and the non-uniformity of stresses inherent in the solder interconnection geometry. In testing at interconnection level, published studies have used testing techniques that don't control deformation at the interconnect and have made uniformity of stress (and strain) approximations that are mostly invalid. Developing constitutive models from such data can produce erroneous results. In this study, we first demonstrate tests that control deformation at the interconnection level. We then show how heterogeneous stress distribution in solder interconnects can significantly affect the constitutive modeling of solder alloys and describe the conditions under which approximations may be made in the determination of accurate constitutive models. We validate our approach through experimental testing on Sn3.8Wwt%Ag0.7Wt%Cu solder joints and finite element analysis.

Original languageEnglish (US)
Title of host publicationTenth Intersociety Conference on Thermal and Thermomechanical Phenomena and Emerging Technologies in Electronic Systems, ITherm 2006
Pages977-983
Number of pages7
DOIs
StatePublished - Dec 22 2006
Externally publishedYes
Event10th Intersociety Conference on Thermal and Thermomechanical Phenomena and Emerging Technologies in Electronic Systems, ITherm 2006 - San Diego, CA, United States
Duration: May 30 2006Jun 2 2006

Publication series

NameThermomechanical Phenomena in Electronic Systems -Proceedings of the Intersociety Conference
Volume2006

Other

Other10th Intersociety Conference on Thermal and Thermomechanical Phenomena and Emerging Technologies in Electronic Systems, ITherm 2006
CountryUnited States
CitySan Diego, CA
Period5/30/066/2/06

Keywords

  • Constitutive modeling
  • Interconnect level testing
  • Lead-free solder
  • Solder joint shape/geometry effects

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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  • Cite this

    Bhate, D., Chan, D., Subbarayan, G., & Chiu, T. C. (2006). Solder interconnection specimen design and test control procedure for valid constitutive modeling of solder alloys. In Tenth Intersociety Conference on Thermal and Thermomechanical Phenomena and Emerging Technologies in Electronic Systems, ITherm 2006 (pp. 977-983). [1645451] (Thermomechanical Phenomena in Electronic Systems -Proceedings of the Intersociety Conference; Vol. 2006). https://doi.org/10.1109/ITHERM.2006.1645451