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Direct Local Strain Measurement In Damascene Interconnects

Published online by Cambridge University Press:  01 February 2011

Moustafa Kasbari
Affiliation:
kasbari@emse.fr, EMSE, CMP-GC, Avenue des anemones, Gardanne, N/A, France
Christian Rivero
Affiliation:
christian.rivero@st.com, STMicroelectronics, Rousset, 13106, France
Sylvain Blayac
Affiliation:
blayac@emse.fr, EMSE, CMP-GC, Gardanne, 13541, France
Florian Cacho
Affiliation:
florian.cacho@st.com, STMicroelectronics, Crolles, 38920, France
Ola Bostrom
Affiliation:
Ola.bostrom@st.com, STMicroelectronics, Rousset, 13106, France
Roland Fortunier
Affiliation:
fortunier@emse.fr, EMSE, CMP-GC, Gardanne, 13541, France
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Abstract

A new mechanical stress characterization method has been developed for Damascene copper interconnects. The micro strain gauge based on a rotating beam has been fabricated in situ on a standard industrial CMOS production line. Comparison of the beam deviation in the fabricated sensor with usual geometrical model is discussed. The saturation of the beam deviation leads to an analytical model which takes the stiffness of the anchoring points into account. This model gives a direct value of the local stress in the copper line for different annealing times. We show that this value is different from the one given by a curvature measurement method. The microstructure of the Damascene copper induces a higher stress level than full sheet deposition copper. The sensor was developed to be compatible within a CMOS process. It is suitable for in situ mechanical stress monitoring in Damascene lines and process optimization.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

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