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Stress behavior of electroplated Sn films during thermal cycling

Published online by Cambridge University Press:  31 January 2011

Jae Wook Shin*
Affiliation:
Brown University, Providence, Rhode Island 02912
Eric Chason
Affiliation:
Brown University, Providence, Rhode Island 02912
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

The mechanical behavior of electroplated Sn thin films was investigated using thermal-expansion induced strain. For stress above a threshold value, the stress relaxation observed during the thermal cycles is well-described by a power law creep mechanism with exponents similar to those of the bulk material. However, the stress relaxation showed significant thickness dependence so that the relaxation in thicker films is faster than thinner films. The surface oxide was also shown to have a considerable effect on retarding the relaxation by inhibiting diffusion to the surface. The relevance of the stress relaxation to whisker formation in Sn-based coatings is discussed.

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Articles
Copyright
Copyright © Materials Research Society 2009

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