Low temperature hybrid wafer bonding for 3D integration

Techniques for the bonding of wafers and dies at low temperature are investigated. Controlled wet etching using acids is used to bond SiO
₂
-SiO
₂
and Al-Al chips at room temperature. The bond strength is evaluated using die-shear tests. Infrared imaging and SEM analysis are used to inspect the bonding interface. The results are compared with data from fusion bonding experiments. Relatively high bond bond strengths for SiO
₂
and Al-terminated chips are achieved using bonding at room temperature.