A Rapid, Controlled and Selective Etching Tool for Bonded Wafer Processing

Physical Sciences, Inc. (PSI) proposes to develop an etching tool based upon its patented Fast Atom Sample Tester (FAST) technology that addresses a critical processing problem faced by manufacturers of Bonded wafers. The fabrication process for bonded wafers results in a 5 mm wide strip of partially delaminated silicon along the perimeter of the 8-in. wafer which can serve as a source of unacceptable particle contamination. This 25¿m thick damage area must be removed by a fast (5 min/wafer), all-dry method which does not remove the underlying Si02 layer. The proposed etching tool employs the FAST technology to generate a uniform, hyperthermal (2 to 15 eV translational energy) fluorine atom beam, concentrated over the delaminated film. The unique characteristics of the FAST technology including its tunable translational energy range, low ion content, and pulsed nature enable high rate, selective, damage-free, and controlled removal of the delaminated film which meets the stated processing goals. The technology is demonstrated on 8-in. bonded wafers in the Phase I program. In Phase II, a commercial prototype etching tool would be fabricated. The proposed effort includes a collaboration with SiBond, a leading producer of bonded wafers that will assure the etching tool meets industry requirements.