Influence of air exposure time on bonding strength in Au-Au surface activated wafer bonding

In this paper, we investigated the influence of air exposure time after gold (Au) deposition on bonding strength in Au-Au bonding. Synthetic quartz glass wafers with smooth Au thin film (thickness: 30 nm, root mean square surface roughness: 0.43 nm) were successfully bonded in air at room temperature after argon radio frequency plasma activation process, even when they were exposed to air for a long term (800-2000 h) after Au deposition. High die-shear strength was obtained and the fractures typically occurred inside the bulk glass during die-shear test rather than at the bonded interface.