Low Temperature Cu-Cu Thermo-compression Bonding for Advanced Micro-System Packaging

Low-temperature wafer-level Copper (Cu)-Copper (Cu) thermo-compression bonding has been an attractive choice in terms of its compatibility for microelectronics metallization and its lower cost. To achieve Low temperature Cu-Cu thermo compression bonding, copper oxide should be removed on the surface of the metal. In this paper, the effectiveness of the acetic acid pretreatment for removal of copper oxide before bonding is analysed. The thermo compression bonding is carried out at 2500C for 1 hr followed by 30 min annealing. Further to find the quality of bonding, different characterization techniques are carried out such as dicing of wafers, bond strength test, and SEM analysis.