The purpose of this project is to investigate the wetting behaviors of Sn3-xAg0.5CuxIn (SAC-In) (x = 0.5 wt%, 1 wt%, and 2 wt%) alloys at various temperatures (250 degrees C, 280 degrees C, and 310 degrees C) on copper (Cu) substrate in argon (Ar) atmosphere. The contact angles (theta) of alloys were gaged by sessile drop technique. The alloys' microstructures were examined by scanning electron microscopy/energy dispersive spectroscopy. Intermetallic compounds of Cu3Sn, Cu6Sn5, and Ag3Sn were observed at the interface of SAC-In/Cu. The results of wetting tests represent that the addition of 1 wt% In improves the wetting properties of the Sn-3 wt%Ag-0.5 wt%Cu (SAC305) alloy. The lowest theta was obtained as 35.55 degrees for Sn-2 wt%Ag-0.5 wt%Cu-1 wt%In alloy at 310 degrees C.