Single-crystal-like Cu joints with high strength and resistance to fatigue failures

Recrystallization and Grain Growth in Cu-Cu Joints under Electromigration at Low Temperatures

“…Therefore, the wind force of EM may play a critical role in the grain growth across the bonding interface. Ong et al reported that large grain growth can be triggered in the Cu joints at a temperature above 250 • C for 1 h [23]. In the present study, the temperature was lowered to 150 • C due to EM.…”

“…This finding is crucial for Cu joints, because their EM lifetime can be prolonged when the bonding interface is eliminated. Ong et al reported that large grain growth can be triggered in the Cu joints at a temperature above 250 °C for 1 h [23]. In the present study, the temperature was lowered to 150 °C due to EM.…”

“…Such a bonding condition was favorable for the good bonding strength and low thermal budget of the joints. According to our previous study [23], Cu-Cu joints could be bonded at 150 • C under a bonding pressure of 41.5 MPa. However, the Cu-Cu joints bonded at 200 • C and 41.5 MPa possessed a higher bonding strength and thermal fatigue resistance.…”

“…Furthermore, the recrystallization of Cu could eliminate the voids at the bonding interface, which leads to enhanced bonding quality [22]. In our previous study [23], single-crystal-like (SCL) Cu joints without bonding interfaces exhibited high resistance to thermal fatigue failure. Yet the temperature had to exceed 250 • C to grow the SCL Cu joints.…”