Characterization of crack fronts in a WLCSP package

Experiments and models for application of a multiscale fracture theory

Dennis Chan, Dhruv Bhate, Ganesh Subbarayan, Luu Nguyen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Extensive failure analysis was performed on identical, isothermally cycled wafer-level chip scale packages with. Sn3.8wt%0.7wt%Ag (SAC387) solder joints. Packages were periodically removed during the cycling process to observe crack front progression. The packages were dipped in liquid nitrogen to reduce solder ductility and then pried apart. The crack areas were observed under an optical microscope. The average crack areas on the corner and mid-edge joints of the package were measured using an image processing software. 50 packages were characterized from 240 to 7200 cycles at every 240 cycles. An average of 20 solder joints per cycle was observed to estimate the crack length and area. A finite element model of this package was constructed in ABAQUS. The solder interconnects of the model were given full plastic and creep properties. Using the failure analysis data and the finite element model, the material constant value in a previously developed hierarchal fracture model was calibrated for SAC387. The ability of the model to predict nonintuitive failure initiation sites due to the under bump metallurgy (UBM) geometry is demonstrated. The hierarchal fracture process model was inspired by information theory and continuum thermodynamics. It was earlier proposed to capture the length-scale and temporal hierarchy inherent in quasi-static fracture processes. This single parameter model allows for a non-empirical, geometry independent approach to predicting crack growth by relating equivalent inelastic dissipations and a material constant to the probability of fracture at a material point.

Original languageEnglish (US)
Title of host publicationProceedings of the ASME InterPack Conference 2009, IPACK2009
Pages199-205
Number of pages7
Volume2
DOIs
StatePublished - Jun 30 2010
Externally publishedYes
Event2009 ASME InterPack Conference, IPACK2009 - San Francisco, CA, United States
Duration: Jul 19 2009Jul 23 2009

Other

Other2009 ASME InterPack Conference, IPACK2009
CountryUnited States
CitySan Francisco, CA
Period7/19/097/23/09

Fingerprint

Cracks
Soldering alloys
Experiments
Failure analysis
Chip scale packages
Geometry
Information theory
ABAQUS
Liquid nitrogen
Metallurgy
Ductility
Crack propagation
Creep
Image processing
Microscopes
Thermodynamics
Plastics

ASJC Scopus subject areas

  • Hardware and Architecture
  • Electrical and Electronic Engineering

Cite this

Chan, D., Bhate, D., Subbarayan, G., & Nguyen, L. (2010). Characterization of crack fronts in a WLCSP package: Experiments and models for application of a multiscale fracture theory. In Proceedings of the ASME InterPack Conference 2009, IPACK2009 (Vol. 2, pp. 199-205) https://doi.org/10.1115/InterPACK2009-89402

Characterization of crack fronts in a WLCSP package : Experiments and models for application of a multiscale fracture theory. / Chan, Dennis; Bhate, Dhruv; Subbarayan, Ganesh; Nguyen, Luu.

Proceedings of the ASME InterPack Conference 2009, IPACK2009. Vol. 2 2010. p. 199-205.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Chan, D, Bhate, D, Subbarayan, G & Nguyen, L 2010, Characterization of crack fronts in a WLCSP package: Experiments and models for application of a multiscale fracture theory. in Proceedings of the ASME InterPack Conference 2009, IPACK2009. vol. 2, pp. 199-205, 2009 ASME InterPack Conference, IPACK2009, San Francisco, CA, United States, 7/19/09. https://doi.org/10.1115/InterPACK2009-89402
Chan D, Bhate D, Subbarayan G, Nguyen L. Characterization of crack fronts in a WLCSP package: Experiments and models for application of a multiscale fracture theory. In Proceedings of the ASME InterPack Conference 2009, IPACK2009. Vol. 2. 2010. p. 199-205 https://doi.org/10.1115/InterPACK2009-89402
Chan, Dennis ; Bhate, Dhruv ; Subbarayan, Ganesh ; Nguyen, Luu. / Characterization of crack fronts in a WLCSP package : Experiments and models for application of a multiscale fracture theory. Proceedings of the ASME InterPack Conference 2009, IPACK2009. Vol. 2 2010. pp. 199-205
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