Microscale Ag particle paste for sintered joints in high-power devices

Abstract

Recently, the sintering behavior of nanoparticles has attracted significant interest for high-power devices. However, nanoparticle pastes are relatively expensive, and require a high proportion of dispersants, solvents, and other organic materials. These organic materials tend to remain in the joint layer, forming voids in the layer after heating, and resulting in large volumetric changes upon evaporation. To avoid such problems, joints using an only-microscale Ag particle paste were produced, and the strength of the joints was evaluated using a shear test. Two different-sized discs were successfully bonded under a nitrogen atmosphere using the microscale Ag particle paste. The shear strength of the joints for the oxygen-free and electroless nickel immersion gold-finished Cu discs was more than 20 and 30MPa, respectively.