Microstructure, Wettability and IMC Formation of Low-Ag SAC Solder on Cu Substrate

Abstract:

This Paper Reports the Microstructure, IMC Evaluation and Wettability of Low-Ag Sn-Ag-Cu(SAC) (0.3 Wt% Ag and 0.5 Wt% Ag) and SAC305 Solder Alloys in Reflowed and Agedconditions. Reflow was Done at 250°C and Thermal Aging at 150°C For100 Hours. Microstructure of Bulk Solder and the IMC Formed at Interfacebetween Solder and Cu Substrate were Observed Using SEM Equipped with EDX. Microstructureobservation Showed Finer β-Sn Dendrites at 0.3%Ag Indicating a Possiblerefining Effect of Lower Ag on Bulk Solder Microstructure. SEM Result Showedfiner Ag₃Sn Distributed in the Solder but the IMC Thickness of Bothreflowed and Aged Solder Joint Seems to Increase with Decreasing Ag Content.This could be due to Finer β-Sn Dendrites which Provide more Diffusion Paththrough Grain Boundaries and Increase IMC Thickness. Similarly, Lower Ag Content Appears to have Detrimental Effect on Wettability and Wetting Angle Ofsolder Joint.

• Periodical: Advanced Materials Research (Volume 1024)
• Pages: 223-226
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1024.223
• Online since: August 2014
• Authors: Maslinda Kamarudin, Mohd Sharif Nurulakmal*, Abu Seman Anasyida
• Keywords: Intermetallic Compound (IMC), SAC Solder, Solder Joint, Thermal Aging, Wettability

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