Reliability modeling for ball grid array assembly with a large number of warpage affected solder joints

Y. W. Chan, T. H. Ju, Saeed A. Hareb, Y. C. Lee, Jih Shun Wu, Mirng Ji Lii

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


A reliability model is established to study thermal fatigue behavior of solder joints in plastic ball grid array (PBGA) assemblies. The model is able to simulate a configuration with a large number of warpage affected solder joints. For efficient computation, regression models are used to calculate the force acting on each solder joint to determine its height under different warpage conditions. With the height and specified solder parameters, the shapes of selected solder joints are calculated using the Surface Evolver. In addition, the displacements of these solder joints can be determined by a macro model using equivalent beams to represent hundreds of solder joints. With the shapes and displacements, three-dimensional micro models for the selected joints are established to compute strain energy densities during temperature cycling. The energy densities can be used to estimate fatigue lives through an empirical correlation. Two PBGA assemblies with 72-I/O cavity-up and 540-I/O cavity-down packages are studied using the reliability model. Silicon chip size and substrate thickness are critical to solder fatigue in the cavity-up assembly. Their effects are reduced substantially for the cavity-down assembly, which is more reliable due to small global thermal mismatch. However, its reliability is strongly affected by the warpage. The warpage changes the shapes of solder joints and can reduce the corner joint's fatigue life from 20,000 to 7800 temperature cycles for an arch-type warpage of 0.28 mm across a 42.5 mm×42.5 mm region.

Original languageEnglish
Pages (from-to)246-253
Number of pages8
JournalJournal of Electronic Packaging, Transactions of the ASME
Issue number3
Publication statusPublished - Sept 2002

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Mechanics of Materials
  • Computer Science Applications
  • Electrical and Electronic Engineering


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