Effect of in addition on Sn-3.5Ag solder and joint with Cu substrate

Citation
Wk. Choi et al., Effect of in addition on Sn-3.5Ag solder and joint with Cu substrate, MATER TRANS, 42(5), 2001, pp. 783-789
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Material Science & Engineering
Journal title
MATERIALS TRANSACTIONS
ISSN journal
1345-9678 → ACNP
Volume
42
Issue
5
Year of publication
2001
Pages
783 - 789
Database
ISI
SICI code
1345-9678(200105)42:5<783:EOIAOS>2.0.ZU;2-T
Abstract
The effect of In addition on the binary eutectic Sn-3.5Ag (compositions are all in mass% unless specified otherwise) solder alloy was investigated. Th e phase equilibrium and the thermodynamic behaviors were examined up to an indium level of 11.5. The addition of about 9In lowered the liquidus temper ature below 210 degreesC, and the microstructures of the solder and the mor phology of secondary phases in the solder matrix changed accordingly. The s econdary phases coarsened in aging at 150 degreesC up to 500 h. However, th e coarsening had little effect on the hardness of the solder alloys. Though the surface tension between the solder and the vapor increased with an inc rease in In content, the wetting angle over the Cu substrate decreased. Thi s was explained by the increased driving force for formation of the interme tallic compound (IMC) at the interface between the Sn-3.5Ag-In solder and t he Cu substrate and thereby the decreased surface tension between the solde r and the substrate.