Wafer-to-wafer fusion bonding of oxidized silicon to silicon at low temperatures

Abstract In this paper a silicon wafer-to-wafer bonding process is presented where silicon dioxide is used as an intermediate layer. Because the process temperature is very low (120 °C) and because the chemical treatment of the surface before bonding does not damage aluminium patterns, wafers containing electronic circuity can be bonded. The oxide layer gives an electrical insulation between the two wafers. High bond strengths (over 20 MPa) are obtained.