Effects of reflow processing and flux residue on ionic migration of lead-free solder plating using the quartz crystal microbalance method

Citation
H. Tanaka et al., Effects of reflow processing and flux residue on ionic migration of lead-free solder plating using the quartz crystal microbalance method, MATER TRANS, 42(9), 2001, pp. 2003-2007
Citations number
5
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Material Science & Engineering
Journal title
MATERIALS TRANSACTIONS
ISSN journal
1345-9678 → ACNP
Volume
42
Issue
9
Year of publication
2001
Pages
2003 - 2007
Database
ISI
SICI code
1345-9678(200109)42:9<2003:EORPAF>2.0.ZU;2-A
Abstract
To investigate the ionic migration, quite a new measurement method has been developed by the authors, which enables real time monitoring of the growth process of ionic migration using a QCM (Quartz Crystal Microbalance). This research has focused on the QCM method to study the growth process of ioni c migration in various types of lead-free solder plating and the effects of the reflow processing and flux residue of soldering processes. In addition , we investigated the anode dissolution characteristics of the elements in each type of solder alloy by measuring the current-potential curve in 0.1 k mol m(-3) KNO3 solution. When using Sn-3.5 mass%Ag solder plating, reflow p rocessing segregates the stable compound Ag3Sn layer and Sn layer. The Sn l ayer selectively promotes the anode dissolution reaction, increasing the oc currence of migration. When using Sn-9 mass%Zn solder plating, the Sn effec tively prevents the excessive dissolution reaction of Zn, However, since re flow processing causes each element to separate out, reflow processing less ens the effectiveness of Sn, thus promoting the occurrence of migration. Th e flux processing of lead-free solders suppresses anode dissolution and eff ectively prevents the occurrence of migration. However, with Sn-9 mass%Zn, the lowered adhesion between the flux film and the electrodes is a factor i n speeding the growth of migration.