Interfacial microstructure evolution and properties of Sn-0.3Ag-0.7Cu-xSiC solder joints

The impacts of SiC on the wettability, mechanical properties and growth of intermetallic compound (IMC) of the low silver Sn-0.3Ag-0.7Cu (SAC0307) -xSiC composite solders paste prepared by mechanical mixing were investigated. It is found that there is an improvement in the wettability and a large reduction in the thickness of IMC with increasing SiC content, such as the contact angle shrinks by 11.48% and the thickness of IMC at the interface decreases by 63% with 0.10 wt% SiC addition. Meanwhile, according to the fracture morphology analysis, the IMC grains are refined repeatedly with increasing SiC content before less than 0.06 wt%, then agglomerated SiC and brittle phase Ag3Sn appear with further increase in SiC content. As a result, the tensile strength of solders joint increased continuously up to the maximum value of 30.49 MPa with 0.06 wt% SiC addition.

Automated summary

The addition of SiC can improve the wettability and tensile strength of low silver Sn-0.3Ag-0.7Cu composite solders, as well as decrease the thickness of IMC. However, when the SiC content exceeds a certain amount, the IMC grains begin to agglomerate and brittle phases appear, leading to a decrease in tensile strength.