Author： Wei Tan Chee Daud Abdul Razak
Publisher： Emerald Group Publishing Ltd
ISSN： 1356-5362
Source： Microelectronics International, Vol.19, Iss.2, 2002-06, pp. : 38-43
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Abstract
A Cu-Al bonding system exists when copper wire is bonded onto an aluminum bond pad using thermosonic wire bonding technology. Aged Cu-Al bonding system was analyzed by measuring the intermetallics layer thickness and its correlation to electrical contact resistance. Result shows that the thickness of Cu-Al intermetallics layer grows almost linearly to aging time. The activation energy needed for Cu atoms to diffuse into Al was calculated using Fick's law; Q=129.66 kJ/mole and D0=1.628×10-4 m2/s. The calculation of activation energy and impurity diffusity using Model Kidson also shows linear relationship. Electrical resistance of Cu-Al intermetallics layer was calculated from contact resistance of Cu-Al bonding system. The result shows that the electrical resistance of Cu-Al intermetallics layer increases linearly with intermetallics thickness. Its growth rate that was calculated using Model of Braunovic and Alexandrov is double of Model of Murcko.
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