The SAC305 (SnAg3.0Cu0.5) alloy belongs to a family of Pb-free solders recommended for joining of various components in electronic devices. This paper is focused on examination of solderability of the SAC305 alloy in contact with glass-epoxy laminates having different finishing (either metallic coatings of HASL LF-lead-free, ENIG-gold and OSP-organic coating) and using various fluxes (EF2202 and RF800). The solderability of the alloy was examined by wetting balance method at 260oC for 3s contact that allows the measurements of both wetting force and wetting time, as well as the estimation of contact angle.
The results show that the type of finishing has a strong effect on the maximum value of wetting force and wetting time. For the SAC305 alloy the shortest wetting time was noted with organic coating while the golden coating shows the longest wetting time. For selected testing conditions, the role of flux type on the solderability of the SAC305 alloy was negligible.
Acknowledgment: The work has been carried out within research project “Improving the reliability of lead-free soldered joints in electronic packages” No. WND-POIG.01.03.01-00-103/09 financed from EC structural funds and the Ministry of Science and Higher Education of Poland