Effects of Bonding Temperature and Pressure on the Electrical Resistance of Cu/Sn/Cu Joints for 3D Integration Applications
This study reports the effects of bonding conditions (temperature and pressure) on the bonding morphology and electrical resistance of a Cu/Sn/Cu structure. By carefully characterizing the bond using several analytical methods [scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM)], we have learned that bonding the samples under various conditions produces greatly different bond morphologies, as well as different prevailing phases in the bonded layer. However, measurements of the electrical resistance of the joints reveal a relative insensitivity to the bonding conditions, signaling that the microstructural evolution and the bond morphology do not strongly influence the resistance.