Effect of cooling rate on microstructure and strength properties of tin-silver-copper solder ball bonding

Citation
K. Noguchi et al., Effect of cooling rate on microstructure and strength properties of tin-silver-copper solder ball bonding, MATER TRANS, 42(5), 2001, pp. 761-768
Citations number
16
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
761 - 768
Database
ISI
SICI code
1345-9678(200105)42:5<761:EOCROM>2.0.ZU;2-A
Abstract
The microstructure and the strength property of Sn-3.5 mass%Ag and Sn-2.5 m ass%Ag-0.8 mass%Cu solder ball bonding formed at various cooling rates were investigated. The grain size of Sn phase and the lamellar space depended o n the cooling rate Re. The reaction layer was thinner and the grain size of Sn phase coarsened when solder balls containing Cu were used. The reaction layer formed between Sn-3.5 mass%Ag and Cu pad was composed of (Ni-Au, Ag) (3)Sn-4. (Ni-Au, Ag)(3)Sn-2 and (Ni-Au, Ag)(3)Sn precipitates. (Cu-Ni, Au, Ag)(6)Sn-5 was formed in the bonding interface when the ball with Cu was us ed. The lamellar space in both balls became smaller at faster cooling rates and was proportional to Re(-1/2). The micro Vickers hardness of the solder ball with Cu decreased slightly at the slower cooling rates because of the grain size and lamella coarsening. The shear strength of joint using Sn-2. 5 mass%Ag-0.8 mass%Cu was a little higher than that using Sn-3.5 mass%Ag at the slower cooling rate because of the fine lamellar structure.