Microstructural evolution of Cu/Sn/Cu joints and effect of temperature on three-dimensional morphology of IMCs in packaging technology

A 4 μm thick Sn film was deposited on the copper substrate by electroplating. Two copper substrates with electroplated Sn were constituted of a Cu/Sn/Cu structure. 240℃ and 1 N were chosen as soldering temperature and pressure to be soldered for different time to investigate the law of microstructural evolution of IMCs. The three-dimensional morphology of Cu₆Sn₅ and Cu₃Sn under different soldering temperature(240, 270, 300℃) were fabricated, Investigate the effect of temperature on three-dimensional morphology. The results show Cu₆Sn₅ was planar after soldered for 30 min and turned into scallop-like with the increase of soldering time. Cu₃Sn in the bottom of scallop was thicker than that in bottom of scallop on both sides. Sn was reacted with the increase of soldering time, Cu₆Sn₅ in the two side merged into a whole gradually. Increase more soldering time, Cu₆Sn₅ continued to be transformed into Cu₃Sn. The three-dimensional of Cu₆Sn₅ transformed from polyhedron shape to procumbent and the size of Cu₃Sn grains decreased gradually with the increase of soldering temperature.