In-Situ Particle Removal in Ion Implanters

Particles on the wafer surface during oxygen implantation (SIMOX technology) lead to buried oxide isolation failure and thereby limit the yield of rad-hard IC's fabricated on SIMOX. This program will explore the use of inertial and electrostatic forces for the in-situ removal of particles from the wafer surface. Since a major contribution to the total particle count is attributed to the implanter itself, an in-situ method is necessary. A special endstation has been designed and built for the Ibis 1000 implanter which has provisions for taking advantage of the spinning hub inertial forces to remove particles. Also, fixtures have been provided to use the implant ion's charge as well as an electron shower to control the wafer and particle potentials, to facilitate the removal of particles by electrostatic force. The combination of these methods will reduce particles and BOX pinholes by at least 2X from the levels achieved in current production SIMOX material.