In-situ observation on electrochemical migration of lead-free solder joints under water drop test

Author

Xia, Y.H. ; Jillek, W. ; Schmitt, E.

Author_Institution

Coll. of Mech. Eng., Zhejiang Univ. of Technol., Hangzhou

fYear

2008

fDate

28-31 July 2008

Firstpage

1

Lastpage

5

Abstract

Electrochemical migration (ECM) of lead-free solder joints were investigated by water drop test method. Nine types solder pastes were employed to compare the ECM susceptible. The effects of applied voltage, electrodes spacing and flux residue on the ECM were in-situ observed. The microstructure and composition of the growing dendrites during ECM were detected. The results revealed that higher voltage and narrower spacing weakened the ECM reliability of solder joints. The flux residua inhibited the occurrence of ECM. The main migration element was Pb in Pb-bearing solder joints. For Sn-Ag-Cu solder joints, it was Sn and Cu to migrate during the ECM process. Zn was the only migration element in the SnZnBi solder joint. Sn-Zn-Bi solder exhibited the best ECM reliability.

Keywords

bismuth alloys; copper alloys; dendrites; electromigration; silver alloys; solders; tin alloys; zinc alloys; SnAgCu; SnZnBi; dendrites; electrochemical migration; flux residua; lead-free solder joints; microstructure; reliability; water drop test method; Electrochemical machining; Electrodes; Environmentally friendly manufacturing techniques; Lead; Microstructure; Soldering; Testing; Tin; Voltage; Zinc;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Packaging Technology & High Density Packaging, 2008. ICEPT-HDP 2008. International Conference on

Conference_Location

Shanghai

Print_ISBN

978-1-4244-2739-0

Electronic_ISBN

978-1-4244-2740-6

Type

conf

DOI

10.1109/ICEPT.2008.4607147

Filename

4607147