In this study, solder joints mixed with graphene-nanosheets (GNSs) were investigated for the manufacture of highly reliable electronic devices. In order to analyze the effect of adding GNSs, experiments were performed by adding various amounts of GNSs (0.01, 0.05, 0.1, 0.3, 0.5 wt%). To compare and analyze the properties of the solder joints to which GNSs were added, shear forces were measured, and cross-sectional observation was performed. The bonding strength of the solder joints containing 0.05% GNSs was the highest, and the bonding strength of the solder joints with higher GNSs contents did not increase. This is because, as the content of GNSs increases, the viscosity of the solder paste also increases; therefore, the solder paste detachability from the metal mask was lowered and a sufficient amount was not applied. In addition, due to the high content of GNSs, the fluidity of solder powder and paste decreased, resulting in defects in the shape of the solder joint. Therefore, the optimal GNSs content in this study was 0.05%, and studies for optimal viscosity should be continued.
