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Measurement and Modeling of Intrinsic Stresses in CVD W Lines

Published online by Cambridge University Press:  15 February 2011

Jin Lee
Affiliation:
Intel Corporation, Santa Clara, CA.
Qing Ma
Affiliation:
Intel Corporation, Santa Clara, CA.
Thomas Marieb
Affiliation:
Intel Corporation, Santa Clara, CA.
Anne S. Mack
Affiliation:
Intel Corporation, Santa Clara, CA.
Harry Fujimoto
Affiliation:
Intel Corporation, Santa Clara, CA.
Paul Flinn
Affiliation:
Intel Corporation, Santa Clara, CA.
Bruce Woolery
Affiliation:
Intel Corporation, Santa Clara, CA.
Linda Keys
Affiliation:
Intel Corporation, Santa Clara, CA.
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Abstract

We have studied stress states in chemical vapor deposited (CVD) tungsten (W) for both blanket films and lines, to understand better the mechanical implications of intrinsic stress for interconnection structures. Since W has a low mobility at its deposition temperature, a very large intrinsic stress develops during deposition. Intrinsic strains in blanket W films were measured with an X-ray technique. The measured strains correspond to a biaxial tensile stress of the order of 1 GPa. This result was used to provide an initial strain input in a finite element calculation to obtain intrinsic stress states in W lines. SEM observation of cross sections of the metal lines enabled us to determine the growth pattern of the W, and infer the boundary conditions during growth. Finite Element Method (FEM) calculations of the room temperature stress in the lines, including both intrinsic and thermal components, are in good agreement with X-ray determinations.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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