Microstructural analysis of reballed tin-lead, lead-free, and mixed ball grid array assemblies under temperature cycling test

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Lei Nie - , University of Maryland, College Park (Author)
  • Maik Mueller - , Chair of Electronic Packaging Technology (Author)
  • Michael Osterman - , University of Maryland, College Park (Author)
  • Michael Pecht - , University of Maryland, College Park (Author)

Abstract

In this study, ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (SAC305) solder balls were reballed with Sn-37Pb solder balls. Three different reballing methods were used. The non-reballed lead-free BGAs were assembled with SAC305 and Sn-37Pb solder pastes to form the lead-free and mixed assemblies. The reballed Sn-Pb BGAs were assembled with Sn-37Pb solder paste to form the reballed Sn-Pb assemblies. All assemblies were subjected to a temperature cycling test with a temperature range of -55°C to 125°C. For the same component type, the reballed BGA assemblies showed similar temperature cycling reliability regardless of the reballing methods. However, the temperature cycling reliability of the reballed assemblies was worse than that of the mixed and the lead-free assemblies. The mean cycles-to-failure of the mixed assemblies was larger than or equal to that of the lead-free assemblies. Failure analysis revealed that the failure site in reballed Sn-Pb assemblies was located in the bulk solder at the component side regardless of the component type and the reballing method, indicating that the reballing method did not influence the crack propagation in reballed assemblies. The mixed assemblies had the same failure site as the lead-free assemblies, i.e., in the bulk solder at the component side. The microstructure differences between the tin-lead, lead-free, and mixed assemblies are also discussed in detail.

Details

Original languageEnglish
Pages (from-to)1218-1232
Number of pages15
JournalJournal of electronic materials
Volume39
Issue number8
Publication statusPublished - 18 May 2010
Peer-reviewedYes

Keywords

Keywords

  • Failure analysis, Reballed BGA, Reliability, Sn-Ag-Cu, Sn-Pb, Temperature cycling