Development of fluxes for selected Sn-Cu based lead-free solders

Author

Yang, Min ; Liu, Xiuzhong ; Wang, Chunqing ; Zou, Zengda ; Jiang, Dalei

Author_Institution

Sch. of Mater. Sci. & Eng., Shandong Univ., Jinan, China

fYear

2005

fDate

30 Aug.-2 Sept. 2005

Firstpage

258

Lastpage

261

Abstract

Fluxes which are suitable for Sn-0.8Cu and Sn-0.8Cu-3Bi lead-free solder have been investigated in this paper. Fluxes were evaluated in spread test by measuring the spread areas of solders on copper substrate. The effect of flux on the intermetallic compounds (IMCs) at the interface between solder and copper substrate was studied through analyzing the morphology of IMCs of interface by electron probe microanalysis (EPMA). Results show that both NST flux (flux consists of natural rosin and SnCl₂) and SAT flux (by adding SnCl₂ into stearic acid ) can greatly improve the wetting ability of Sn-Cu based lead-free solder on copper substrate. SnCl₂ in flux influences the morphology and thickness of IMCs at the interface of solder/Cu joint. The concentration of SnCl₂ contained in fluxes also affects the spread areas of solder on copper plate.

Keywords

copper alloys; electron probe analysis; materials testing; solders; surface morphology; tin alloys; NST flux; SAT flux; SnCl₂; SnCuBi; electron probe microanalysis; interface morphology; intermetallic compounds; lead-free solders; spread test; wetting ability; Area measurement; Conducting materials; Copper; Electronics packaging; Environmentally friendly manufacturing techniques; Lead; Materials science and technology; Morphology; Testing; Tin;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Packaging Technology, 2005 6th International Conference on

Print_ISBN

0-7803-9449-6

Type

conf

DOI

10.1109/ICEPT.2005.1564733

Filename

1564733