Cu-Cu Wiring: The Novel Structure of Cu-Cu Hybrid Bonding

We have developed the novel structure of Cu-Cu hybrid bonding called “Cu-Cu wiring”. The Cu-Cu wirings have been formed through hybrid bonding of Cu lines. The new CMP process has been developed to form the various wiring patters at bonding interface. The investigation of electrical properties and reliabilities has showed the satisfactory performance of Cu-Cu wirings for the next-generation 3D stacked devices. The mechanisms that wafer bonding misalignment has degraded the electrical properties of Cu-Cu wirings have been also investigated.