Silicon on insulator material by Wafer Bonding

Thermal bonding of oxidized silicon wafers is used to obtain high-quality silicon on insulator (SOI) starting material for electronics and sensor applications. An overview of the technology is followed by a detailed description of the bonding technique and the ensuing wafer thinning processes for making SOI of various film thicknesses. Bonded pairs of wafers can be reproducibly produced free of contact voids. Thick-film SOI is produced using a simple bond and grind/polish technique. Thin-film SOI, suitable for CMOS applications, is produced using the bond and etch back (BE-SOI) process. A comparison of selective etch-back chemistry with different etchstop fabrication techniques is presented. These methods produce inexpensive, low-defect SOI, for integrated circuit applications, using materials and equipment common to silicon integrated circuit process lines.