An analytical model to compute thermal stresses in passivated metal interconnects is proposed in this article. Typical aspect ratio of passivated metal interconnects is 1 or less (frequently between 0.5 and 1). Previous Eshelby-based analytical model by Niwa et al. [J. Appl. Phys. 68, 328 (1990)] is not very accurate as it fails to take into account the proximity of the interconnect to the free surface of the passivation. A recently proposed model by Wikström et al. [J. Appl. Phys. 86, 6088 (1999)] precisely does not work when the aspect ratio < 1. The analytical model proposed in this letter can predict stresses (average and spatial variations) in passivated metal interconnects with superior accuracy. The effect of free surface of passivation is fully taken into account and comparisons with previous works are presented.

Topics
Thermal effects, Passivation
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© 2001 American Institute of Physics.
2001
American Institute of Physics
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