Investigation of rheology behavior of lead-free solder paste

Solder paste is the most important strategic bonding material used in the assembly of surface mount devices in electronic industries. Rheology of solder paste is the most important parameter which affects the paste printing process, the reflow soldering performance, and wherefore the resulting solders joint quality and reliability. A clear understanding of the complicated interactions among various key ingredients of flux will be very beneficial for developing future high performance solder pastes. This paper presents results of investigation of rheology behavior of Sn-3Ag-0.5Cu lead-free solder pastes with various fluxes. The impacts of different filmogens, solvents and thixotropic agents on the viscosity, thixotropy of solder paste have also been discussed and concluded.