Theoretical and experimental determination of Cu diffusivity in eutectic Sn–Ag system at 235–280 °C

摘要: Abstract This study evaluated the Cu diffusion and dissolution behaviors in eutectic Sn–Ag alloy with a mathematical model combination experimental data. The was performed at temperatures ranging from 235 °C to 280 °C Cu/Sn–3.5Ag solder bump joint, where substrate solid but Sn–3.5Ag liquid all of examined. coefficient (DCu) respect temperature, activation energy (Q), average concentration (Cavg) as function time (t) were investigated via this metallurgical system. coefficients DCu 1.2(± 0.4) × 10− 9 m2/s (235 °C), 2.4(± 0.6) × 10− 9 m2/s (250 °C), 2.6(± 0.7) × 10− 9 m2/s (265 °C), 3.9(± 1.6) × 10− 9 m2/s (280 °C), which are same order those acquired capillary-reservoir technique for bulk Cu/Sn system by Ma Swalin 1969. Q estimated based on Arrhenius relation approximately 13.3 kJ/mol 235–280 °C, reflecting insensitivity temperature. A calculated Cavg–t profile predicted that Cavg approaches saturation after 70 s agrees well experiments. modeling results consistent literature data, indicating proposed is an effective method represent diffusion/dissolution behavior confined alloy.