Cohesive fracture mechanics based numerical analysis to BGA packaging and lead free solders under drop impact

Yao Yao*, Leon M. Keer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Lead free solders are replacing lead rich solders in the electronic industry, the performance and safety of lead free solder interconnects in electric packaging under drop impact becomes a critical concern of semiconductor and electronic product manufacturers. Compared with the lead rich solder alloy, lead free solder alloy typically has higher rigidity and lower ductility. The presence of the Intermetallic Compound (IMC) layer can also affect the drop impact response of the solder interconnect, which may lead to quasi-brittle solder/IMC interfacial fracture. The traditional drop test is expensive and time consuming, and it is quite difficult to observe the full dynamic responses during the drop impact. In the present study, numerical analysis is performed to investigate drop impact effect on ball grid array (BGA) electronic packaging with the intention of predicting the performance of solders under drop impact and providing the fundamental understanding required to design a reliable electric packaging. A three dimensional finite element model is developed to simulate the solder interconnect and electronic packaging failure under board-level drop impact. An impact analysis procedure coupled with sub-modeling technique is established. The Cu6Sn5 and Cu3Sn IMC layers are incorporated in the solder interconnects model; cohesive fracture mechanics based method is applied to predict the crack initiation and propagation near the IMC/solder interface. A lead-free solder alloy constitutive relationship comprising elastic and rate dependent plastic effects is incorporated in the computational model.

Original languageEnglish (US)
Pages (from-to)629-637
Number of pages9
JournalMicroelectronics Reliability
Issue number4
StatePublished - Apr 2013

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Safety, Risk, Reliability and Quality
  • Surfaces, Coatings and Films
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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