The effect of CNT and Cu on interfacial intermetallic growth of Sn-Ag-Cu solder

摘要

In this study,the effect of copper and carbon nanotubes(CNT)composition on interfacial growth of various Sn-Ag-Cu(SAC)solder joints were investigated.SAC is proven to have good reliability and mechanical properties but lacking in terms of melting point and wettability.Thus,Sn-4.0 wt%Ag-0.3wt%Cu(SAC403)and Sn-4.0 wt%Ag-0.7 wt%Cu(SAC407)were reinforced with CNT with various weight percentages of 0 to 0.1 wt%.The wetting angle and intermetallic compound(IMC)thickness is measured using optical microscope(Olympus BX5/M)and Olympus Stream Essentials software.The high Cu content alloys formed a long Cu6Sn5 whisker which act as an obstacle to crack propagation.CNT improves wettability and IMC layer growth for both SAC403 and SAC407 by lowering the wetting angle and IMC thickness compared to the plain solder.