The influences of Ag nanoparticles on voids growth and solderability about Sn3.0Ag0.5Cu/Cu solder joint

Abstract

Although Sn3.0Ag0.5Cu solder (SAC305) has higher reliability, there are a large number of harmful voids in solder joints. Larger voids can reduce thermal conductivity of solder joints. However, as a microstructure growth inhibitor, the influences of Ag nanoparticles on voids growth are not clear at present. Herein, we prove that Ag nanoparticles can increase SAC305 solderability, but promote voids growth. Ag nanoparticles and SAC305 solder paste were mixed by mechanical stirring for 0.5 h. Next, SAC305-xAgP (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 wt%) was obtained. The results indicated that solder solderability was improved increasingly with Ag nanoparticles addition. The lower the amount of nanoparticles added, the greater the final loss. After being aged at 100 °C for 150 h, the voids stopped growing. Due to the violent reaction between Ag nanoparticles and flux, the final voids growth rate became faster, and the average voids size changed from 14.34% to 24.91%.