Effect of thermal aging on board level drop reliability for Pb-free BGA packages

Tz-Cheng Chiu, Kejun Zeng, Roger Stierman, Darvin Edwards, Kazuaki Ano

Research output: Contribution to journalConference articlepeer-review

342 Citations (Scopus)


The drive for Pb-free solders in the microelectronics industry presents several new reliability challenges. Examples include package compatibility with higher process temperatures, new solder compound failure mechanisms, and the selection of the proper Pb-free alloy to maximize product lifetime. In addition to the challenges posed by the Pb-free material conversion, the migration of market focus from desktop computing to portable applications is changing the critical system failure mode of interest from conventional temperature cycling (T/C) induced solder fatigue opens to drop impact induced solder joint fracture. In this paper a study was conducted to investigate the influence of intermetallic compound (IMC) growth on the solder joint reliability of Pb-free ball grid array (BGA) packages under drop loading conditions. Thermal aging at homologous temperatures between 0.76 and 0.91 with microstructural analysis was conducted to analyze the solid phase IMC growth at the solder to BGA pad interface. Component level ball shear and pull tests were also conducted to investigate the aging effect on solder joint strength. A key finding from this work is that Kirkendall voids formed at the bulk solder to package bare Cu pad interface under relative low 100°C aging. Void formation and coalesce is shown to be the dominant mechanism for solder joint strength and board level drop reliability degradation.

Original languageEnglish
Pages (from-to)1256-1262
Number of pages7
JournalProceedings - Electronic Components and Technology Conference
Publication statusPublished - 2004 Dec 28
Event2004 Proceedings - 54th Electronic Components and Technology Conference - Las Vegas, NV, United States
Duration: 2004 Jun 12004 Jun 4

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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