Electrostatic levitator for hard disk media

This article discusses recent developments in contact-less and zero-charge electrostatic levitators for use in Ultra-High-Vacuum (UHV) and clean environments. Presented is the first demonstration of an electrostatic levitation technology which can suspend disk-shaped metals and alloys. A 3.5 inch diameter aluminum hard disk media has been suspended successfully by actively controlling an electrostatic attractive force acting on it. This article describes the basic principle of electrostatic suspension, the structure of an experimental levitator, electrode design, position feedback control method, a linear system model, and operational procedures. Experimental data are also presented. The electrostatic levitation technology will be a key technique in the developments of contact-less and zero-charge wafer manipulation and transportation equipments utilized in UHV and clean environments, both of which are necessary for the manufacture of the new generation semiconductor devices.