A merged MEMS-CMOS process using silicon wafer bonding

A process for fabricating integrated silicon micromachined sensors is demonstrated. The process uses silicon wafer bonding to create a substrate that can be inserted into an existing IC fabrication line without perturbation of the line. After circuits are completed, micromachining steps are performed to release the silicon membranes and form the sensors. A variety of test structures including MOSFETs, piezoresistive pressure sensors and cantilever beams were successfully fabricated, and all were functional, indicating that the additional micromachining steps and CMOS thermal cycles caused no adverse effects to the devices