Growth Behaviour of Intermetallic Compounds in Sn-3.0Ag-0.5Cu Solder Joints under Annealing Treatment with Various Temperatures

In this paper, the growth behaviour of intermetallic compounds in line-type Cu/Sn-3.0Ag-0.5Cu (SAC305)/Cu solder joints under annealing treatment with various temperatures was investigated. The line-type Cu/SAC305/Cu solder joint specimens were manufactured using a line-type mould and a reflow soldering machine. The specimens were classified into 4 groups and 3 of them were annealed under 75°C, 150°C and 210°C for 12 hours, respectively. The other group of specimens was set as a comparison without any annealing treatment. The tensile test was conducted after specimens were carefully ground. The applied load and deformation response of SAC305 solder joint specimens under different annealing conditions at the strain rate of 10
^-4
s
^-1
were measured. The cross-section of the interface between solder alloy and Cu rod in the specimens was observed by a scanning electron microscope. In order to characterize the regularity of the IMC growth, the averaged thickness of the IMC layer was calculated statistically using graphic software. In accordance with the averaged thickness of the IMC layer after the annealing duration of 12 hours, the interdiffusion coefficients of the Sn and Cu atoms were calculated. The coefficients of Sn and Cu atoms in 75°C, 150°C and 210°C are 1.5565×10
^-17
m
²
/s, 1.4408×10
^-16
m
²
/s and 6.2352×10
^-16
m
²
/s, respectively.