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Three Dimensional Interconnect Stress Modeling for Back EndProcess

Published online by Cambridge University Press:  17 March 2011

Xiaopeng Xu
Affiliation:
TCAD R&D, Synopsys, Inc. 700 E. Middlefield Rd, Mountain View, CA 94043, USA
Victor Moroz
Affiliation:
TCAD R&D, Synopsys, Inc. 700 E. Middlefield Rd, Mountain View, CA 94043, USA
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Abstract

A process oriented approach is demonstrated for modeling the stressevolution during the entire back end process flow. No ad hoc assumptions regarding stress states are made for layerdeposition and etching. Intrinsic stresses from material formation, thermalmismatch stresses from temperature ramps, stress relaxation due to viscousdeformation, and stress profile redistribution upon deposition and etchingare all considered at each process. Parametric studies are carried out toexamine the effects of viscous flow, material selection and layoutvariations. It is found that the viscous flow of the passivation anddielectric materials have large impact on stress evolution. A TCAD assisteddesign approach is suggested for lowering stress levels of critical stresscomponents. The implications of the stress modeling results on reliabilityissues like stress-triggered void formation are discussed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

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