Controlling BGA joint microstructures using seed crystals

Z. L. Ma, S. A. Belyakov, J. W. Xian, T. Nishimura, K. Sweatman, C. M. Gourlay

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

This paper overviews methods to catalyse the nucleation of tin in BGA solder joints and explores the potential of engineering tin nucleation to control joint microstructures. A range of heterogeneous nucleants for Sn is overviewed. It is shown that CoSn 3 , PtSn 4 , PdSn 4 and IrSn 4 can all catalyse Sn nucleation and substantially reduce the nucleation undercooling. The nucleation mechanisms are discussed in terms of a crystallographic lattice matching analysis, where each nucleant is shown to have good planar matching across the closest packed planes in each crystal structure. We then demonstrate an approach to incorporate the nucleants into solder joints as seed crystals to control the orientation of the tin nucleation event. With this approach, it is possible to generate single-crystal joints all with the same c-axis orientation.

Original languageEnglish
Title of host publication2018 7th Electronic System-Integration Technology Conference, ESTC 2018 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781538668139
DOIs
Publication statusPublished - 26 Nov 2018
Externally publishedYes
Event7th Electronic System-Integration Technology Conference, ESTC 2018 - Dresden, Germany
Duration: 18 Sept 201821 Sept 2018

Publication series

Name2018 7th Electronic System-Integration Technology Conference, ESTC 2018 - Proceedings

Conference

Conference7th Electronic System-Integration Technology Conference, ESTC 2018
Country/TerritoryGermany
CityDresden
Period18/09/1821/09/18

Keywords

  • EBSD
  • Pb-free soldering
  • nucleation
  • reliability

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