Journal Published Online: 02 September 2010
Volume 7, Issue 9

Wetting Behaviour and Evolution of Microstructure of Sn–Ag–Zn Solders on Copper Substrates with Different Surface Textures

CODEN: JAIOAD

Abstract

The effect of surface roughness on wetting behaviour and evolution of microstructure of two lead-free solders (Sn-2.625Ag-2.25Zn and Sn-1.75Ag-4.5Zn) on copper substrate was investigated. Both solders exhibited good wettability on copper substrates having rough surface and lower wettabilty on smooth surfaces. The contact angles of solders decreased linearly with increase in surface roughness of the substrate. The exponential power law, ϕ=exp(−Kτn), was used to model the relaxation behaviour of solders. A high intermetallic growth was observed at the interface particularly on copper substrates with rough surface texture. A thin continuous interface showing scallop intermetallic compounds (IMC) was obtained on smooth surfaces. With an increase in surface roughness, the IMC morphology changed from scallop shaped to needle type at the Sn-2.625Ag-2.25Zn solder/substrate interface and nodular to plate like IMCs for Sn-1.75Ag-4.5Zn solder matrix.

Author Information

, Satyanarayan
Dept. of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Srinivasnagar, India
Prabhu, K.
Dept. of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Srinivasnagar, India
Pages: 17
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Details
Stock #: JAI103052
ISSN: 1546-962X
DOI: 10.1520/JAI103052