Whisker formation in Sn and Pb-Sn coatings: Role of intermetallic growth, stress evolution, and plastic deformation processes

Journal Article · Mon Apr 28 04:00:00 EDT 2008 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2912528· OSTI ID:21102005

Chason, E; Jadhav, N; Kumar, K S ^[1]; Chan, W L ^[2]; Reinbold, L ^[3]

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1. Division of Engineering, Brown University, Providence, Rhode Island 02912 (United States)
2. Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)
3. Raytheon Company IDS, Maritime Mission Center, Portsmouth, Rhode Island 02871 (United States)

We have simultaneously measured the evolution of intermetallic volume, stress, and whisker density in Sn and Pb-Sn alloy layers on Cu to study the fundamental mechanisms controlling whisker formation. For pure Sn, the stress becomes increasingly compressive and then saturates, corresponding to a plastically deformed region spreading away from the growing intermetallic particles. Whisker nucleation begins after the stress saturates. Pb-Sn layers have similar intermetallic growth kinetics but the resulting stress and whisker density are much less. Measurements after sputtering demonstrate the important role of the surface oxide in inhibiting stress relaxation.

• OSTI ID: 21102005
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 17 Vol. 92; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COATINGS
COMPRESSION STRENGTH
COPPER
CRYSTAL GROWTH
DENSITY
EVOLUTION
INTERMETALLIC COMPOUNDS
LAYERS
LEAD ALLOYS
NUCLEATION
OXIDES
PLASTICITY
SPUTTERING
STRESS RELAXATION
STRESSES
SURFACE COATING
THIN FILMS
TIN ALLOYS
WHISKERS