Journal of Materials Science

, Volume 42, Issue 7, pp 2347–2357

Microstructural evolution of gold–aluminum wire-bonds

  • Adi Karpel
  • Giyora Gur
  • Ziv Atzmon
  • Wayne D. Kaplan
Article
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Abstract

The purpose of this study is to understand the morphological changes that occur during annealing of Al–Au wire-bonds, by analyzing the interface region of annealed model wire-bonded samples between 5N (99.999%) Au wires and Al pads. Due to the small length scale of the intermetallic region at the interface of the bond, the analysis was done using scanning/transmission electron microscopy combined with energy dispersive spectroscopy. Samples were prepared using a dual-beam focused ion beam system. Microstructural characterization showed that during annealing, a Au-rich intermetallic region was formed under the bond and at the periphery of the bond. Two types of failures occurred during annealing: crack formation at the bond periphery due to an increase in volume during intermetallic growth and the formation of stresses; and oxidation of the AlAu4 phase adjacent to the Au ball, which resulted in the formation of continuous cracks between the Au ball and the intermetallic region. The characteristic void-line found inside the intermetallic region played no part in failure that occurred during exposure to elevated temperatures.

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Adi Karpel
    • 1
  • Giyora Gur
    • 2
  • Ziv Atzmon
    • 2
  • Wayne D. Kaplan
    • 1
  1. 1.Department of Materials EngineeringTechnion – Israel Institute of TechnologyHaifaIsrael
  2. 2.Kulicke & Soffa Bonding ToolsYokneam EliteIsrael

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