Wafer-scale surface activated bonding of Cu-Cu, Cu-Si, and Cu-SiO 2 at low temperature

Wafer scale direct bonding of Cu-Cu, Cu-Si, and Cu-SiO2 was performed at low temperature using surface activated bonding (SAB) method. Successful direct bonding of Cu-Cu and Cu-Si was achieved at room temperature. However, bonding of Cu-SiO2 using SAB process at low temperature failed. In order to integrate Cu to SiO2, two-step surface activation process was adopted. The copper was exposed to Ar ion beam and SiO2 was exposed to oxygen plasma, …