N2 Tunnel Wafer Transport System

A wafer transport system has been developed for application to the next generation of ULSI manufacturing processes. In this system, various kinds of wafers ranging from 8 to 12 in. are floated on a gas film to be transported through an ultraclean N2 gas environment with no solid contact. A sensor controls the movement of the transported wafer on the control unit precisely and rapidly (i.e., a sensor instantly detects and recognizes the configuration of the wafer and lets the wafer stop, facing tin the right direction. In this ultraclean N2 gas environment, the wafer surface is free from particle contamination and growth of native oxide. Furthermore, moving the electrostatic clamping device on the track, and the jet flow of ultraclean N2 gas against the track, allows self-cleaning of the wafer transport track.