Sn-3.5Ag/Cu 界面金属间化合物的生长行为研究

An investigation was carried on the formation and growth of intermetallic compound (IMC) at the interface between Sn-3.5Ag lead free solder and the Cu substrate. During soldering, due to the existence of solubility of Cu, the dissolution of the IMC would occur as long as the liquid solder remains unsaturated with Cu. The result indicated that during soldering, the thickness of the IMC layer was related with its dissolution rate. According to the adsorption effect, nano-size Ag₃Sn particles formed on the IMC surface. During aging at 70, 125 and 170°C up to 1000 h, the initial scollop IMC layer changes into a plane shape. The IMC thickness is linearly proportional to the square root of aging time, which reveals a diffusion-controlled mechanism during aging. The activation energies values for the growth of the total IMC layers and Cu₆Sn₅ IMC layer are 75.16 kJ/mol and 58.59 kJ/mol respectively.