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Effects of Dielectric Thermal Expansion and Elastic Modulus on the Stress and Deformation Fields in Copper Interconnects

Published online by Cambridge University Press:  01 February 2011

Yu-Lin Shen*
Affiliation:
shenyl@me.unm.edu, University of New Mexico, Mechanical Engineering, MSC 01 1150, Albuquerque, NM, 87131, United States
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Abstract

This study aims at assessing the role played by the coefficient of thermal expansion (CTE) and elastic modulus of low-k dielectric, in affecting the stress and deformation fields in copper interconnects. Parametric finite element analyses are conducted, varying one parameter at a time, for gaining fundamental understanding of the effect of individual properties. The analyses are based on a three dimensional model containing two levels of metal lines connected by a via. It is found that both the high CTE and low modulus values of the polymer-based dielectric contribute to the evolution of stress/strain fields in the metal structure. The low-k CTE plays a more significant role. Within certain limits, decreasing the low-k CTE and/or increasing the low-k modulus can help alleviate the plastic deformation, and thus the propensity of damage initiation, in the metal. Reducing the low-k CTE will be a more efficient and safer approach.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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