Effect of Thermal Aging on the Impact Strength of Soldered Bumps under Formic Acid Atmosphere

Abstract

In this study, we have investigated the effect of thermal aging on impact strength of Sn-Ag-Cu solder bumps in fluxless soldering process using formic acid atmosphere. We conducted impact tests on as-reflowed and thermally-aged solder bumps, which were fabricated on either formic acid atmosphere or a liquid flux. The results indicated that the morphology of the intermetallic compound layers in samples soldered using formic acid was similar to those soldered with the liquid flux, after soldering and after thermal aging. The fluxless solder bumps, using formic acid atmosphere, have impact strengths similar to the solder bumps obtained using the liquid flux in nitrogen atmosphere