Adi Karpel - Academia.edu (original) (raw)
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Papers by Adi Karpel
Journal of Materials Science, 2007
In this study the interface morphology of a model 99.999% (5N) Au wire bonded to Al pads in the a... more In this study the interface morphology of a model 99.999% (5N) Au wire bonded to Al pads in the as-bonded state was examined by scanning/transmission electron microscopy with energy dispersive spectroscopy. Specimens for transmission electron microscopy were prepared using the lift-out method in a dual-beam focused ion beam system. Analysis of the bond microstructure was conducted as a function of the Al pad content and as a function of the bonding temperature. Additions of Si and Cu to the Al pad affect the morphology and the uniformity of the interface. A characteristic-void line is formed between two intermetallic regions with different morphologies in the as-bonded samples. According to the morphological analysis it was concluded that a liquid phase forms during the bonding stage, and the void-line formed in the intermetallic region is the result of shrinkage upon solidification and not the Kirkendall effect.
Journal of Materials Science, 2007
The purpose of this study is to understand the morphological changes that occur during annealing ... more 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 AlAu 4 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.
Journal of Materials Science, 2007
In this study the interface morphology of a model 99.999% (5N) Au wire bonded to Al pads in the a... more In this study the interface morphology of a model 99.999% (5N) Au wire bonded to Al pads in the as-bonded state was examined by scanning/transmission electron microscopy with energy dispersive spectroscopy. Specimens for transmission electron microscopy were prepared using the lift-out method in a dual-beam focused ion beam system. Analysis of the bond microstructure was conducted as a function of the Al pad content and as a function of the bonding temperature. Additions of Si and Cu to the Al pad affect the morphology and the uniformity of the interface. A characteristic-void line is formed between two intermetallic regions with different morphologies in the as-bonded samples. According to the morphological analysis it was concluded that a liquid phase forms during the bonding stage, and the void-line formed in the intermetallic region is the result of shrinkage upon solidification and not the Kirkendall effect.
Journal of Materials Science, 2007
The purpose of this study is to understand the morphological changes that occur during annealing ... more 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 AlAu 4 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.