Microstructure and Properties of SiC Whisker Reinforced Sn-0.3Ag-0.7Cu Solder Alloy

In the present study, the effects of SiC whiskers on the microstructure of the SAC0307-xSiC (x = 0 wt.%, 0.02 wt.%, 0.04 wt.%, 0.06 wt.%, 0.08 wt.% and 0.10 wt.%) composite solders and their related properties have been investigated. The results showed that the appropriate addition of SiC whiskers (< 0.10 wt.%) significantly refined the precipitated phases (Ag3Sn and Cu6Sn5), enhanced the wettability and hardly affected the melting point of the composite solders. Additionally, the admixture of SiC whiskers inhibited the growth of the interfacial intermetallic compound (IMC) layer between the composite solder and Cu substrate during reflow soldering. The thickness of IMCs was reduced from 2.52 mu m for the plain SAC0307/Cu to 1.93 mu m with 0.10 wt.% SiC whisker addition. Moreover, when the amount of SiC whisker addition reached 0.06 wt.%, the shear strength of solder joints reached a maximum 28.0 MPa, 55.6% higher than that of the pristine counterpart, and then decreased because of the agglomeration of SiC whiskers with the increase of SiC whisker content.